JPH0690355B2 - Focus detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detection device used for a camera or the like, and more particularly to a focus detection device that illuminates a subject with auxiliary light to detect a focus state.

2. Description of the Related Art A focus detection device that detects the focus state based on the subject image signal obtained by receiving the subject light through a shooting lens provides accurate focus detection results when the subject is dark and the contrast of the subject image is low. Can't get Therefore, conventionally, when it is determined that focus detection cannot be performed in an operation mode in which auxiliary light for illuminating a subject is not provided and the auxiliary light is not emitted (auxiliary light non-emission mode), a mode in which the auxiliary light is emitted (auxiliary light emission There is proposed a focus detection device (hereinafter referred to as a conventional device) in which focus detection can be performed by illuminating with auxiliary light by switching to a mode) (for example, Japanese Patent Laid-Open No. Sho.
60-52810 publication).

However, even in the above conventional apparatus, when the subject is far away from the auxiliary light or when there is an obstacle in front of the shooting lens by chance (for example, when shooting in a crowd, when a person is in front of the shooting lens, In the case of standing), focus detection was still impossible even in the auxiliary light emission mode. In the above-described conventional apparatus, when it is determined that focus detection cannot be performed in the auxiliary light emission mode in this manner, the subsequent focus detection is set not to be performed.

Problems to be Solved by the Invention According to the above-described conventional device, if it is determined that focus detection is impossible in the auxiliary light emission mode, focus detection is not performed thereafter, so even if the camera is separated after that. Even if the focus detection is possible by pointing it in the direction of
There is a problem in that focus detection is not performed and a photo opportunity is missed.

This problem can be solved by configuring the focus detection to be repeated subsequently, but if focus detection is repeatedly performed in the auxiliary light emission mode, a large amount of power is consumed to emit the auxiliary light. Further, another problem that the deterioration of the light source of the auxiliary light becomes severe occurs.

Therefore, an object of the present invention is to solve the above problems, reduce power consumption, prevent deterioration of the light source of auxiliary light, and quickly respond to changes in the situation of the subject. It is to provide a detection device.

Means for Solving Problems A focus detection device according to the present invention is based on a light receiving unit that receives subject light that has passed through a photographing lens and outputs a subject image signal, and a subject image signal that is output from the light receiving unit. Based on a subject image signal output from the light receiving means, focus detecting means for detecting the focus state of the photographing lens, auxiliary light illuminating means for illuminating a subject for detecting the focus state by the focus detecting means. Determination means for determining whether or not the focus state can be detected; a first operation mode for operating the focus detection means without operating the auxiliary light illuminating means; and a subject for operating the auxiliary light illuminating means. Mode setting means for selectively setting a second operation mode for operating the focus detection means in a state where the first operation is performed by the mode setting means. When the mode is set and when the determination unit determines that the focus state cannot be detected, the switching for controlling the mode setting unit to switch to the second operation mode for setting. Means and the second operation mode is set by the mode setting means, and when the determination means determines that the focus state cannot be detected, the first operation mode is hereafter described. Control means for controlling the mode setting means so as to be fixedly set to, and controlling the focus detecting means so that the focus detecting means repeats the operation.

EXAMPLE An outline of a camera system for automatic focusing according to an example of the present invention will be described with reference to FIG. In Fig. 1, the left side of the alternate long and short dash line is the interchangeable lens (LZ) and the right side is the camera body (BD).
07) mechanically connecting terminals (JL1) to (JL5) (JB
1) ~ (JB5) electrically connected. In this camera system, the subject light that has passed through the lens system of the interchangeable lens (LZ) passes through the semi-translucent part in the center of the reflection mirror (108) of the camera body (BD), and is reflected by the sub mirror (109) CCD. The optical system is configured so that the image sensor (FLM) receives light.

The interface circuit (112) is a focus detection module (A
Driving the CCD image sensor (FLM) in the FM)
It captures subject data from the image sensor (FLM) and sends this data to the AF controller (113). The AF controller (113) calculates the signal of the defocus amount | ΔL | that indicates the amount of deviation from the in-focus position and the defocus direction (front pin, rear pin) based on the signal from the CCD image sensor (FLM) To do. The motor (MO1) is driven based on these signals, and its rotation is the slip mechanism (SLP), drive mechanism (LDR), camera body side clutch (10
It is transmitted to the interchangeable lens (LZ) via 7). The slip mechanism (SLP) prevents the motor (MO1) from being overloaded by slipping when the driven part of the interchangeable lens (LZ) is subjected to a torque larger than a predetermined value.

Focusing is performed by moving the lens system in the optical axis direction via the transmission mechanism (105). An encoder (ENC) for monitoring the drive amount of the lens (FL) is connected to the drive mechanism (LDR) of the camera body (BD), and the encoder (ENC) changes the drive amount of the lens (FL) A corresponding number of pulses are output.

Here, the number of rotations of the motor (MO1) is NM (rot), the number of pulses from the encoder (ENC) is N, the resolution of the encoder (ENC) is ρ (1 / rot), and the rotation axis of the motor (MO1) is the encoder. Reduce the reduction ratio of the mechanical transmission system up to the (ENC) mounting shaft to μ
P, the reduction ratio of the mechanical transmission system from the rotary shaft of the motor (MO1) to the camera body side clutch (107) is μB, and the reduction ratio of the mechanical transmission system from the lens side clutch (106) to the large gear (103) is μL. , LH (mm / rot) for the helicoid lead of the focus adjustment member (102) and Δd (mm) for the movement amount of the focusing lens (FL), N = ρ · μP · NM Δd = NM · μB · μL · LH That is, the relational expression of Δd = N · μB · μL·LH / (P · μP) (1) is obtained.

Further, when the ratio of the movement amount ΔL (mm) of the image plane when the lens is moved by Δd (mm) and the above Δd is represented by Kop = Δd / ΔL (2), it can be expressed by equation (1) ( From 2), the relational expression of N = Kop · ΔL · ρ · μP / (μB · μL·LH) (3) is obtained. Here, if KL = Kop / (μL·LH) (4) KB = ρ · μP / μB (5), then the relational expression of N = KB · KL · ΔL (6) is obtained. .

In the equation (6), ΔL is obtained from the signal processing circuit (112) as a defocus amount | ΔL | and a signal in the defocus direction.

Further, KB in the equation (5) is data fixedly determined according to the reduction ratio μB in the camera body, and this data KB
Is owned by the camera controller (111).

Here, from the camera main body side reading circuit (LDC) to the lens side lens circuit (LEC), power is supplied via terminals (JB1) (JL1) and synchronization clock is supplied via terminals (JB2) (JL2). A read start signal is sent to each pulse via terminals (JB3) (JL2). In addition, data K is transferred from the lens circuit (LEC) to the reading circuit (LDC) via terminals (JL4) (JB4).
L is output in series. The terminals (JB5) (JL5) are common ground terminals.

When a read start signal is input via the terminals (JB3) (JL3), the lens circuit (LEC) synchronizes the KL data with the clock pulse input from the camera body via the terminals (JB2) (JL2). And outputs them in series to the reading circuit (LDC). Then, the reading circuit (LDC) reads the serial data from the terminal and converts it into parallel data based on the same clock pulse as the clock pulse output to the terminal (JB2).

The camera controller (111) uses the data KL from the reading circuit (LDC) and the data KB inside it as KL · KB = K.
Is calculated. The AF controller (113) calculates the defocus amount | ΔL | using the data of the subject image from the interface circuit (112), and this defocus amount | ΔL |
And the data K from the camera controller (111), K · | ΔL | = N is calculated to calculate the number of pulses to be detected by the encoder (ENC). The AF controller (113) rotates the motor (MO1) clockwise or counterclockwise through a motor driver circuit (114) according to a defocus direction signal obtained using the subject image data, and an encoder (EN
When the number of pulses equal to the value N calculated by the AF controller (113) is input from C), the focusing lens (FL)
Is determined to have moved by the amount of movement Δd to the in-focus position,
Stop the rotation of the motor (MO1). In the above explanation,
The data KB was fixedly stored on the camera body (BD) side, and the value K = KL · KB was calculated by multiplying this data KB by the data KL from the lens. It is not limited. For example, if the interchangeable lens can be attached to any of several types of camera bodies with different KB values, the lens circuit (LEC) of the interchangeable lens (LZ)
To output the data of K1 = KL · KB1 corresponding to the camera body having a specific KB value according to the set focal length.
On the other hand, in the camera body of this specific model, the data KB in the camera controller (111) and the data K1 from the reading circuit (LDC) are not necessary for the calculation of KL / KB and the AF controller (1
13) and have a value KB2 (≠ KB1) different from the above specific KB value, when the above lens is mounted on another camera body, the KB2 / KB1 value in the camera controller (111) You may make it have data and perform the operation of K2 = K1 · KB2 / KB1 = KL · KB2 to obtain the value of KL · KB2.

In particular, in the case of the front group extension type interchangeable lens in which the focusing lens (FL) is arranged in front of the zoom lens (ZL) as described above, the value of Kop is Kop = (f1 / f) ² (7) f1: It becomes the focal length of the focusing lens, and the KL value or K value for one interchangeable lens changes within a very wide range. In this case, the data KL or K stored in the lens is the exponent part data and the significant digit data (for example, in the case of 8-bit data, the upper 4 bits are the exponent portion and the lower 4 bits are the significant digit number). Divided into
If the lower 4 bits of the data read by the reading circuit (LDC) of the camera body is shifted by the exponent data and input to the camera controller (111), K
Even if the value of L or K changes significantly, it is possible to cope with it sufficiently.

Next, in the present system, when the subject is dark and the focus detection apparatus determines that the contrast is low, the subject is irradiated with auxiliary light for focus detection. In this embodiment, the auxiliary light system is incorporated in the flash unit (FL) and attached to the accessory shoe (65) of the camera body. Inside the flash unit (FL), a tube for flash emission (40), an auxiliary light unit (62), an LED (48) as a light source for auxiliary light,
It has a condenser lens (63) and a flash circuit (FLS). The flash circuit (FLS) and the camera controller (111) are electrically connected and signals are exchanged.

In the description of FIG. 1 above, the device of the present invention is shown to be configured by a combination of circuit blocks in order to facilitate understanding of the overall function and operation of the present invention. Most of the functions of the circuit block of (1) are achieved by a microcomputer (hereinafter, referred to as a microcomputer), as described below.

FIG. 2 is a block diagram schematically showing a circuit in the camera of this embodiment.

In Fig. 2, (MNS) is a power switch, and (POR) is a power-on reset circuit that resets the AF microcomputer (MC1) and control microcomputer (MC2), which will be described later, according to the closing of the power switch (MNS). is there. (S1) is a switch that is closed by pressing the shutter release button one step (half-press), and the operation of photometry and automatic focus adjustment is started by this closing. (S2) is a switch that is closed when the shutter release button is pressed (pressed down) in two stages, and the exposure operation is started by this closing. (S4) is a switch that is closed when the winding of the film is completed.

(MC2) is the camera controller (111) shown in Fig. 1.
Is a microcomputer that controls the operation of the entire camera system in a sequence (hereinafter, referred to as a control microcomputer). The switch (S1) is connected to the terminal (I1), and the switches (S2) (S4) are connected to the terminal (I2) via an AND circuit. (OSC) is an oscillator circuit for that operation. (MC1) functions as the AF controller (113) shown in FIG. 1, and is a microcomputer (hereinafter referred to as AF microcomputer) that controls the automatic focusing operation in sequence. The calculated focus adjustment state is displayed in the viewfinder by turning on one of the display LEDs (LEDL) (LEDM) (LEDR).

(SAF / M) Switch for switching between automatic focus adjustment mode (hereinafter referred to as AF mode) and manual focus adjustment mode (hereinafter referred to as nonAF mode).
Mode, when it is open, it becomes nonAF mode, and its SAF
The / M signal is applied to the terminal (PT6) of the control microcomputer (MC2). Here, the non-AF mode is provided with an FA mode in which the lens is not moved because the focus adjustment state is considered to be displayed, and a MANUAL mode in which the display is not performed. (SA / R)
Is the AF priority mode that performs shutter release after the completion of automatic focus adjustment and the switch (S2) even before the completion of automatic focus adjustment
When the shutter is closed, it is a switch that selectively switches between the shutter release priority mode in which the shutter is released according to the closing of the
AF priority mode, when released, it becomes release priority mode, and its SA / R signal is the control microcomputer (MC2) terminal (PT7)
Entered in.

(SS / C) is a switch for switching between continuous AF mode (hereinafter referred to as continuous AF mode) and single-shot AF mode (hereinafter referred to as one-shot AF mode). Switch (SS / C)
When is open, it becomes continuous AF mode,
Even after focusing, it becomes a mode in which automatic focus adjustment is continuously performed. One shot when switch (SS / C) is closed
The AF mode is set, and AF is locked after focusing. This SS / C signal is the control microcomputer (MC2) terminal (PT
It is input to 0).

(MDR2) Motor for winding and rewinding film (MO
2) A driver circuit that controls the rotation direction and amount of rotation of the motor (MO2) by the MM and MN signals from the control microcomputer (MC2). MM, MN signal and motor (MO
Table 1 shows the relationship with the operation of 2).

(EDO) transmits to the control microcomputer (MC2) the manually selected mode among exposure control modes such as program mode / shutter speed priority mode / aperture priority mode / manual mode, and is required for exposure control in that mode. An exposure control setting circuit for transmitting information such as shutter speed, aperture value, film sensitivity, and exposure correction value to the control microcomputer (MC2). (BS1) and (BS2) are the data lines.

(LMC) is a photometric circuit, the ANI signal of which indicates a reference voltage for A / D conversion, the VRI signal of which indicates an analog photometric signal. These are respectively terminals (PT7) (PT7) of the control microcomputer (MC2)
8) has been entered. (EXD) is the control microcomputer (MC2)
An exposure display circuit that displays the proper exposure value (shutter speed, aperture value, etc.) calculated in (BS3) is its data line. (EXC) is the exposure control time that performs exposure control according to the proper exposure value (shutter speed, aperture value, etc.) calculated in the control microcomputer (MC2) and the set exposure value, and (BS4) is the data It is a line.

(FLS) indicates a circuit (hereinafter referred to as a flash circuit) in the electronic flash device attached to the camera.
S) is the terminal (ST
1) Connected to the camera side circuit by (ST2) (ST3) (ST4) (ST5) and (GND). This flash circuit (FL
The details of S) are shown in FIG.

FIG. 3 shows a flash circuit (FLS), in which (20) is a main switch, (22) is a power battery, and when the main switch (20) is closed, the voltage of the power battery (22) is changed. Is boosted by the DC-DC converter (24) and supplied to the main capacitor (28) through the diode (26).
(GND) is the ground terminal. The charge voltage of the main capacitor (28) is monitored by the charge monitor circuit (30), and when the voltage reaches a predetermined amount, the charge completion detection circuit (3
2) outputs the charge completion signal, which is the AND circuit (3
The terminal (ST2) is reached via 4). On the camera side, after receiving this charge completion signal, it outputs a light emission start signal via the terminal (ST1), which causes the trigger circuit (36).
Is triggered, the SCR (38) becomes conductive and the flash discharge tube (40)
Starts to emit light due to the energy of the main capacitor (28). This light emission start signal is emitted from the light emission start monitor circuit (42).
When the light emission start monitor circuit (42) receives the light emission start signal, the AND circuit (34) is closed to prevent transmission of the charge completion signal to the terminal (ST2). When the camera's photometry circuit (LMC) detects that the correct exposure has been reached, the camera outputs a flash stop signal to the terminal (ST3), and the flash stop circuit (44) receives this flash stop signal. , Stop the light emission of the flash discharge tube (40).

(45) is an AF that is closed to provide auxiliary illumination from the electronic flash device to detect the focus adjustment state when the subject is dark.
When the auxiliary light switch is closed, the terminal (ST5) outputs an AF auxiliary light OK signal indicating that illumination for focus detection by auxiliary light is possible. If the camera determines that this auxiliary light is required, the terminal (ST4)
An AF auxiliary light emission signal is input to the transistor, the transistor (46) becomes conductive, and the auxiliary light LED (48) emits light.

Returning to FIG. 2, (Sx) is the synchro switch of the camera,
(FLB) is a light emission control circuit that controls the light emission time of the electronic flash device. (LEC) and (LDC) are the lens circuit inside the lens and the reading circuit inside the camera, respectively, as in Fig. 1. When the lens is attached to the camera, both circuits are connected to the terminals (JB).
1) to (JB5) and (JL1) to (JL5) are connected to each other. In the figure, (VL) is the power supply, (RES) is the read start signal, (CL) is the clock pulse, (DATA) is the data,
(G) indicates ground respectively. A clock pulse is input from the terminal (SCK) of the control microcomputer (MC2) to the reading circuit (LDC), and the reading circuit (LDC) outputs serial data output from the terminal (TXD) of the control microcomputer (MC2). Lens data is serially input to that terminal (RXD) according to the signal.

(FLM) is the CCD image sensor shown in FIG. 1, (IF1) is the sensor driving interface circuit, and (MDR1) is the first
A driver circuit (ENC) corresponding to (114) in the figure, which controls the drive of the lens driving motor (MO1), is an encoder similar to that in FIG.

4 and 5 are flowcharts showing the operation of the control microcomputer (MC2) of FIG. The operation of the system shown in FIG. 2 will be described below with reference to this flowchart. Before that, the names and contents of the flags used in this embodiment are shown in Tables 2 and 3.

In FIG. 4, when the switch (S1) is closed and an interrupt signal is input to the terminal (I1), the control microcomputer (MC2) starts its operation. First, in step S1, the release flag
Clear RLF. This flag is a flag used to distinguish between continuous shooting (hereinafter referred to as continuous shooting mode) and single-shot shooting (hereinafter referred to as single shooting mode) in the shooting modes of the camera. Here, the continuous shooting mode means the switch (S2)
When it is ON, it refers to the mode in which you can take pictures continuously, and single-shot mode refers to the mode in which one shot can be taken with one switch (S2) turned ON. Next, in S2, the AF microcomputer drive clock CK is supplied from the control microcomputer (MC2) terminal (Xout) to the AF microcomputer (MC1). Next, in S3, serial input / output operations are performed multiple times to capture multiple data from the lens circuit (LEC), and the conversion coefficient (KROM) required for automatic focus adjustment, focusing of auxiliary light source and visible light Position correction data (ΔIR),
Backlash data (BKLSH), AF (automatic focus adjustment)
Or open F value for AF (AFAV0) to judge whether focus detection calculation for FA (focus adjustment status display) is possible,
Lens attachment discrimination (LENSF), presence / absence of AF coupler axis (A
FCF) and whether or not the lens can detect focus (FAENL) are stored in the memory inside the control microcomputer (MC2).
In step S4, data from the exposure control value setting circuit (EDO) that outputs setting data for exposure control and the like is fetched. This includes data relating to exposure and whether to use single-shot or continuous-shot mode. At S5, the AFS signal output from the control microcomputer (MC2) terminal (PT1) is set to "Low". This is input to the interrupt terminal (INT1) of the AF microcomputer (MC1), and the AF microcomputer (MC1) starts operating at the falling edge of this signal. At the same time, IN from the terminal (PT2)
The REL signal is set to "High". This is the AF microcomputer (MC
It is input to the interrupt pin (INT2) of 1), but this interrupt does not occur because the interrupt is taken at the falling edge.

In the flowchart of FIG. 4, there may be a case where a loop is made from S5 to S10 and from S22 to S3. When passing S5 in the loop, the AFS signal falls and the INREL signal rises many times, but since the AFS signal is already "Low" and the INREL signal is "High", there is no interruption to the AF microcomputer (MC1). It does not take. When the operation of the AF microcomputer (MC1) starts, the setting data for the operation of the AF microcomputer (MC1) and the data from the lens are serially sent from the control microcomputer (MC2). In synchronization with the clock signal from the control microcomputer (MC2) terminal (SCK), the control microcomputer (MC2) terminal (TXD) serially outputs 5 bytes of 8-bit data, the contents of which are shown in Table 4. It is input to the pin (TXD) of the AF microcomputer (MC1).

Control microcomputer (MC2), AF microcomputer (MC1) terminal (P1
DTRQ from 1) to control microcomputer (MC2) terminal (PT4)
The signal is regarded as a signal of data request, and data output is started. In the control microcomputer (MC2), this DTRQ signal is "Lo" in S6.
Wait until it becomes "w", and if it becomes "Low", proceed to S7 and send the data. AESIO of S7 makes the data to determine the operation mode of the AF microcomputer (MC1), and sends the data serially However, it is shown as another routine in FIG.

At the beginning of the AESIO routine starting from step S29 in FIG. 5, first, the RAM of the fifth serial data of the control microcomputer (MC2) containing the signals AFFL, RDY, DR, AFC, FAEN is cleared. The FAEN signal is determined in S30, S31, and S32. First S30
Looking at the LENSF signal of the data coming from the lens circuit (LEC),
If LENSF = 0 and there is no lens signal, FAE
The N signal remains “0” and the process proceeds to S33. The lens is attached
When LENSF = 1, if the FAENL signal is “1”, that is, if the lens is capable of focus detection, proceed to S32 and set the FAEN signal to “1”. If the FAENL signal is “0”, the FAEN signal remains “0”. Becomes

Next, in S33 to S35, the AFC signal is determined. Terminal at S33 (PT
Check the SAF / M signal input to 6). The SAF / M signal is a switch that determines whether or not to automatically adjust the focus of the camera lens from the outside of the camera. If it is "High", the AF mode (the focus adjustment status of the shooting lens mounted in the camera body is detected, The mode automatically adjusts the focus of the taking lens according to the result), and if it is "Low", it becomes the non-AF mode. S33
If the SAF / M signal is “0” at, the AFC signal remains “0” at S36.
If it is "1", go to S34 and use the data A from the lens.
Watch the FCF signal. If AFCF signal is "1" in S34, lens AF
Since there is a coupler axis for, set the AFC signal to "1" in S35. That is, when the lens has the coupler axis for AF and the operation switch (SAF / M) of the camera is closed to be on the AF side, the AFC signal becomes "1", and other than that, it is set to "0".

If the drive mode setting of the camera in S36 and S37 is continuous shooting mode, the DR signal is set to "1", and if it is single shooting mode, the DR signal remains "0". Next, in S38 and S39, the signal from the electronic flash device attached to the camera is checked, and if the electronic flash device is attached to the camera and the AF auxiliary light switch (45) is on, the flash circuit (FLS) The terminal (ST5) goes into the "High" state and enters the terminal (PT11). At S38, PT11 =
If it is "High", the AFFL signal is set to "1" in S39. This is a signal to the AF microcomputer (MC1) that the AF auxiliary light can be emitted. (Details will be described later.) Set the RDY signal in S40 and S41. When charging of the electronic flash device is completed, the terminal (ST2) of the flash circuit (FLS) goes into the "High" state, and this is input to the terminal (PT9). Therefore, if PT9 = "High" in S40, go to S41. Go ahead and set the RDY signal to "1". This signal is also used at the time of focus detection using auxiliary light described below (hereinafter referred to as auxiliary light AF mode). The SCF signal is set in S42 and S43. Switch (SS /
If C) is closed, the signal input to the terminal (PT0) is "Low", so set SCF to 1. If the switch (SS / C) is open, the terminal (PT0) is "High", and the signal SCF remains 0. And S44
The data sent from the lens by the AF microcomputer (MC1)
Set to serial transfer register for sending to. In S45, set the CSAF signal for starting serial transfer to "Hig
Set to h ". This is a response to the DTRQ signal of the serial transfer request from the AF microcomputer (MC1).
When it becomes "h", the AF microcomputer (MC1) starts capturing the serial data. Then, in S46, transfer the 8-bit 5-byte data to the AF microcomputer (MC1). In S47, return the CSAF signal to "Low" and perform serial transfer. Ends.

Next, return to the main routine of FIG. 4 and perform the next step.
Go to S8. Here, from the photometry circuit (LMC),
Taking in the NI signal and the VRI signal of the reference voltage for A / D conversion,
A / D convert the photometric output and prepare it as the data required for exposure calculation. Next, in S9, the exposure calculation for the constant light and the flash light is performed. At the next step S10, it is checked whether the terminal (I2) of the control microcomputer (MC2) is "Low" to see if the release has been made. If the shutter is charged, the switch (S4) is on, the release button is pressed in two steps, and the switch (S2) is turned on, the terminal (I2) should be "Low". Terminal (I2) is "High"
If so, proceed to S25 because it has not been released. In S25, the release flag RLF is cleared. Then, in step S26, it is determined whether or not the charging completion signal is received from the electronic flash device, and if the charging completion signal is received, S2
The process proceeds to 7 to send the flash light photographing data to the display unit (EXD), and if the charging completion signal is not received, the process proceeds to S28 to send and display the stationary light photographing data to the display unit (EXD), and the process proceeds to Step S22. Then, in step S22, it is determined whether the terminal (I1) is "Low" with the switch (S1) still closed, and if it is "Low", the process returns to step S3 and the same operation as described above is performed. repeat.

On the other hand, when it is determined in step S22 that the terminal (I1) is "High", the process proceeds to S23, and the operation of the AF microcomputer (MC1) is stopped. The way to stop is to interrupt the AF microcomputer (MC1) terminal (INT1) with the AFS signal. Start of AF microcomputer (MC1) by AFS signal and AF
In order to distinguish it from the interruption for stop by the S signal, the stop interrupt is made to rise again within less than 50 μs after the fall (see FIG. 17 (B)). If only the metering flow is interrupted from S26 to S28,
Since the AFS signal is “Low”, the stop signal is once “Hig
Release after "h", flow of release S11 ~ S21
When an interrupt occurs, the AFS signal is "High", so the stop signal falls. This interrupt causes the AF microcomputer (MC1) to enter stop mode and stop the automatic focus adjustment operation. In S24, the exposure display on the display (EXD) is turned off, and the control microcomputer (MC2) stops operating.

Next, if photometry is repeated and the flow is released while it is looping, the terminal (I2) becomes "Low". Then S1
Check 0 and go to S11. Next, release flag RL
Check F and if 1, go to S26. This means that if the shutter is released once in single shooting mode, the release flag RLF is set to 1 in S21 to S22, and if the switch (S2) is turned on by pressing the release button two steps,
Not released again. On the other hand, if the switch (S2) is turned off while the switch (S1) is turned on, step S10
From S25, the release flag RLF is cleared. That is, when the switch (S2) is turned on again next time,
It will be released from S11 to S12.

Next, in S12, the AF priority / release priority switching signal input to the terminal (PT7) is checked. Here, the AF priority mode is a mode in which the shutter is released only after focusing is completed by the automatic focus adjustment even if the switch (S2) is turned on.The release priority mode is the focus during automatic focus adjustment. Is a mode that releases any time the switch (S2) is closed. In S12, SA / R signal is "Hig
If h "(SA / R = 1), the AF priority mode is set, and the process advances to S13 to check the AFE signal. This is the AF microcomputer (MC
The AF microcomputer (MC
2) is a signal that becomes “High” when the focus is detected and the focus is determined. In S13, it is determined whether or not it is in focus. If it is in focus, the AFE signal is "1", the process proceeds to S14 and the release is started. AFE signal is "0" in S13
If so, go to S26 and not be released. On the other hand, if the release priority mode is set in S12, the process proceeds to S14 and is released. The SA / R signal checked in S12 is a signal according to the manual selection of the switch attached to the camera, which is also
It is also linked to a self-timer switch (not shown),
When the self-timer is activated, it will switch to the release priority mode even if there is a switch in the AF priority mode. During the self-timer, the release priority mode is set. When using the self-timer, a self-timer time wait (not shown), for example, a time wait of 10 seconds is inserted between S14 and S15. Also, the switch (SA / R) provided on the camera body is connected to the terminal (PT7), but this switch is taken out of the camera body and used for an external controller (for example, a controllable back cover) or a remote controller. You can leave it to the receiver.

Next, in S14, an INREL signal indicating that the release has been made from the terminal (PT2) to the AF microcomputer (MC1) is issued. The INREL signal is input to the interrupt terminal (INT2) of the AF microcomputer (MC1), and the falling edge of this signal causes an interrupt, causing the AF microcomputer (MC1) to jump to the release routine. Then, even if the lens is being driven during automatic focusing, the operation is stopped, the display is turned off, and the release is completed. In S14, the AFS signal is set to "High" in preparation for the end of the next release and the start of the operation of the AF microcomputer (MC1). Next, in step S15, it is determined whether the charging completion signal is input from the flash circuit (FLS) by looking at the terminal (PT9). If it is input, the process proceeds to step S16 and the exposure control data for flash photography is set. Send to the exposure control circuit (EXC), S if the charge completion signal is not input
Exposure control circuit (EXC) for exposure control data for ambient light at 17
Send to. Then, the exposure control operation is started in S18.

When the exposure control operation is completed, the film is automatically wound up in S19. Then, the release flag RLF described above in S20 and S21 is set to "1" in the single shooting mode, and the process proceeds to S22.
If the switch (S1) is still closed and the terminal (I1) of the control microcomputer (MC2) is "Low", step S3
If the switch (S1) is not closed, move to step S23 and perform the same operation as above, then the control microcomputer (MC2) operates. To stop. This concludes the description of the flow of the control microcomputer (MC2).

FIG. 6 is a circuit diagram showing details of the interface circuit (IF1) of this embodiment. The operation of this circuit will be described below.

When the control microcomputer (MC2) detects that the switch (S1), which is closed by pressing the shutter release button one step, is detected by the control microcomputer (MC2), the AF microcomputer (MC1) performs focus adjustment operation according to the signal from the control microcomputer (MC2). Start.

First, the IOS signal from the AF microcomputer (MC1) is set to "Low",
The gate opens in the direction in which the signals of NBφ to NB3 are output from the AF microcomputer (MC1) toward the interface circuit (IF1). Then, the AF microcomputer (MC1) outputs a pulsed integration clear signal ICG to the CCD image sensor (FLM) as a signal of NB2, whereby each pixel of the CCD image sensor (FLM) is reset to the initial state, Output AG of the brightness monitor circuit (MC) built into the CCD image sensor
COS is reset to power supply voltage level. At the same time, the AF microcomputer (MC1) outputs the "High" level shift pulse generation enable signal SHEN from the terminal (NB5). Then, at the same time as the integration clear signal ICG disappears, the integration of photocurrent starts in each pixel in the CCD image sensor (FLM), and at the same time, the output AGCOS of the brightness monitor circuit (MC) drops at a speed according to the brightness of the subject. To start, the reference signal output DOS from the reference signal generation circuit (RS) built into the CCD image sensor is kept at a constant reference level. The AGC controller (406) compares AGCOS with DOS, and controls the gain of the variable gain differential amplifier (408) according to how much AGCOS decreases with respect to DOS within a predetermined time (100 msec. During focus detection). To do. Further, when the AGC controller (406) detects that AGCOS has dropped below a predetermined level with respect to DOS within a predetermined time after the integration clear signal ICG has disappeared, then the "Hi
A gh "level TINT signal is output. This TINT signal is input to the shift pulse signal output circuit (410) through the AND circuit (AN) and the OR circuit (OR1), and in response thereto, this circuit (410). Shift pulse SH is output from T.
The INT signal is taken into the AF microcomputer (MC1) as an NB4 signal through the OR circuit (OR2), and the AF microcomputer (MC1) knows the integration end of the CCD image sensor by this signal. When this shift pulse SH is input to the CCD image sensor (FLM), the photocurrent integration by each pixel ends, and the charge according to this integration value is transferred in parallel to the corresponding cell of the CCD image sensor shift register. . On the other hand, based on the clock pulse CL from the AF microcomputer (MC1), the phase is shifted 180 ° from the sensor drive pulse generation circuit (412).
Two sensor drive pulses φ1 and φ2 are output and input to the CCD image sensor (FLM). Of these sensor drive pulses, the CCD image sensor (FLM) is an OS that discharges the electric charge of each pixel of the CCD shift register from the end in series in synchronization with the rise of φ1 and forms an image signal.
The signals are sequentially output. This OS signal has a higher voltage as the incident light intensity to the corresponding pixel is lower, and the subtraction circuit (414) subtracts this from the above-mentioned reference signal DOS,
(DOS-OS) is output as a pixel signal. If the TINT signal is not output after the integration clear signal ICG disappears and a predetermined time elapses, the AF microcomputer (MC1) outputs "H" from the terminal (NBφ).
The igh "level shift pulse generation command signal SHM is output. Therefore, if the" High "level TINT signal is not output from the AGC controller (406) even after a lapse of a predetermined time after the integration clear signal ICG disappears, this shift In response to the pulse generation command signal SHM, the shift pulse generation circuit (41
0) generates the shift pulse SH.

On the other hand, in the above-described operation, the AF microcomputer (MC1) outputs the sample hold signal S / H when the pixel signals corresponding to the 7th to 10th pixels of the CCD image sensor are output. This part of the CCD image sensor is covered with an aluminum mask for the purpose of removing the dark output component, and the light receiving pixel of the CCD image sensor is in a light-shielded state. on the other hand. The peak hold circuit (416) holds the difference between the output OS and DOS corresponding to the aluminum mask part of the CCD image sensor by the sample hold signal, and this difference output, the pixel signal and the variable gain amplifier (408) are input thereafter. It Then, the variable gain amplifier (408) amplifies the difference between the pixel signal and its difference output with a gain controlled by the AGC controller (406), and the amplified output is amplified by the A / D converter (4
After A / D conversion by 18), A as pixel signal data
Captured by F microcomputer (MC1).

When the pixel signal data is captured, the AF microcomputer (MC
Signal IOS from 1) becomes "High", and NBφ to NB from the interface circuit (IF1) to the AF microcomputer (MC1)
The gate opens in the direction where the 3 signal is output. The A / D conversion of the A / D conversion circuit (418) is performed by 8 bits, but the upper 4 bits and the lower 4 bits are transferred to the AF microcomputer (MC1).
The switching timing of the upper and lower 4 bits is EOC
It is done by signals. The EOC signal is ORed with the TINT signal by the OR circuit (OR2) and input to the AF microcomputer (MC1) as the NB4 signal. AF microcomputer (MC1) is this NB
Depending on the timing of the “High” and “Low” states of the four signals
Pixel signal data will be fetched from NBφ to NB3.
Also, from this NBφ to NB3, before the acquisition of the pixel signal data is started, the AGC controller (406) controls the AGC.
It is designed to capture data. This AGC data is
As will be described later, it is used as a judgment level. In addition, the Sφ signal output from the terminal (NB1) of the AF microcomputer (MC1) is used to initialize the CCD image sensor.
This is a signal for switching between normal operation for integrating the subject light.

After that, the AF microcomputer (MC1) sequentially stores this pixel signal data in the internal memory. When the data corresponding to all the pixels of the image sensor is saved, the AF microcomputer uses it to defocus according to a predetermined program. And the direction thereof are calculated and displayed on the display circuit, while the lens driving device is driven in accordance with the amount of defocus and the direction thereof to automatically adjust the focus of the taking lens.

In the present embodiment, the integration of the CCD image sensor (FLM), the data dump, and the focus detection calculation are repeated to improve the accuracy.

7 to 16 are flowcharts showing the operation of the AF microcomputer (MC1). First, Tables 5-1, 2, and 3 show the flags used in this flowchart.

There are four entrances to start the operation of the AF microcomputer (MC1). In other words, when the power is turned on, that is, when the RES signal comes to the terminal (CLR1) of the AF microcomputer (MC1) in FIG. 2, “RESET” (step # 1 in FIG. 7), the terminal of the control microcomputer (MC2) ( Issue to start AF operation (automatic focus adjustment operation) or FA operation (focus detection operation) from PT1)
"INT1S" (step # 8 in FIG. 7) started when the AFS signal is input to the pin (INT1) of the AF microcomputer (MC1), the AF microcomputer (MC1) from the terminal (PT2) of the control microcomputer (MC2) I give it out to let you know that I have released
"INT2S" (step # 27 in Fig. 8) started when the NREL signal is input to the terminal (INT2) of the AF microcomputer (MC1), and the PS signal from the encoder (ENC) is the terminal of the AF microcomputer (MC1). “INT3S” (step # 252 in FIG. 16) started by being input to (INT3) corresponds to these four. The main routine of the flow of the automatic focus adjustment operation starts from step "INT1S" in step # 8 in FIG. 7 and passes through "AFSTART" in step # 33 in FIG. 9 and "CDINTS" in step # 44 in FIG. 11 Flow to “MAIN1” in step # 86 in FIG. From "MAIN1", it is roughly divided into three, from the flow of low contrast where the contrast of the subject is low starting from "LOWCON" in step # 165 in Fig. 13 and "LSAVE" in step # 238 in Fig. 14 Auxiliary light AF mode that starts (it is a mode that illuminates the subject with the auxiliary light LED (48) to detect the focus when it is dark and focus detection is not possible) and step # 91 in FIG. The flow is for normal AF mode, in which the contrast of the subject begins with "NLOC1" and is sufficiently high. As a subroutine, a flow for inputting and processing serial data from the control microcomputer (MC2) starting with “SIOSET” in step # 241 in FIG. 15 and focus detection “CKLOC in step # 196 in FIG.
There is a flow for determining the end position of the lens starting from "K". The automatic focus adjustment operation (hereinafter referred to as AF operation) and the focus detection operation (hereinafter referred to as FA operation) in this embodiment will be described below based on this flowchart.

First, in response to the closing of the power switch (MNS), a reset signal RES is output from the power-on reset circuit (POR), and this control signal causes the control microcomputer (MC2) to move from a specific address. At the same time, the clock pulse CK is output from the terminal (Xout) of the control microcomputer (MC2). This is input to the terminal (Xin) of the AF microcomputer (MC1). When the reset signal RES is input to the terminal (CLR1) under the clock pulse CK from the control microcomputer (MC2), the AF microcomputer (MC1) starts from “RESET” in step # 1.
Step # 1 clears all the flags (Tables 5-1, 2, and 3) used in the flowchart. Each flag is set to "0" in the initial state. From step # 2, to stop AF or FA operation from the control microcomputer (MC2) to the AF microcomputer (MC1),
Although a stop signal as will be described later is output, this step # 2 is also passed when this stop command is input.

In step # 2 (hereinafter “step” is omitted), the signal from the terminal (ST4) input to the terminal (P13) is brought to the “Low” state and the illumination by the auxiliary light LED (48) is turned off. This is the switch (S1) while the auxiliary light is emitting in auxiliary light AF mode.
This is because the light emission is stopped when the focus detection operation is stopped by opening. In # 3, the focus adjustment status display or defocus direction display in AF or FA operation is turned off. Here, "High" is output to the terminals (P32) to (P30) and erased, but this is done by setting each terminal to the input mode. Even if the display is erased by this method, the output state being displayed is stored in the output port register, and the stored content can be displayed again by setting this port in the output mode. We will use this later.

In # 4, the lens is stopped. The brake is not applied here. This is because, while the AF microcomputer (MC2) is not operating, the lens is not braked so that it can be moved relatively easily by hand, and power saving is considered. The control of the lens motor drive signals MC, MR, MF, and MB that are input from the AF microcomputer (MC2) to the driver circuit (MDR1) are shown in Table 6 and the terminal (PO2).
By setting the signals MR, MF, and MB of ~ (PO0) to the "High" state, the electric brake is not applied and the motor (MO1) is de-energized and the lens stops.

In Table 6, * indicates that either "H" or "L" may be used.

In # 5, when a stop command is received from the control microcomputer (MC2) during the release operation or the fill AF mode, the release flag (No. 5-1
This is a step of clearing the release F) in the table and the auxiliary light mode flag (the auxiliary light mode F in Table 5-2). # 6
Is a control for determining the interrupt status for starting the next flow. After the operation of the AF microcomputer (MC1) stops, INT1S of # 8 or INT of # 28
It allows starting from 2S. However, in actuality, when the shutter release button (not shown) for the camera is pressed by one step, the switch (S1) in FIG. 2 is closed and the control microcomputer (MC2) interrupts INT1, and the shutter release button is pressed by two steps. Switch (S2) is closed and IN
Since the release interrupt is applied to T2, the start of the next flowchart starts with "INT1S" in # 8.
become. At # 7, the AF microcomputer (MC1) enters stop mode. Stop mode means that the AF microcomputer (MC1) enters the power saving mode and stops operating. At this time, the status of each terminal is only "Low" for P13 and "High" for others, the LED for auxiliary light illumination (48) is turned off, and the LED for display (LEDL) (LE
DM) (LEDR) is off, the lens is in the stop state, and the interface circuit (IF1) is also in the stop state. In this state, the next control microcomputer (MC2)
Waiting for start of interrupt from pin to INT1.

Next, # 8 which is the second entrance of the above-mentioned flowchart
Let's move on to the explanation of "INT1S". The interrupt start from this "INT1S" does not disable the interrupt during the entire flow of the AF microcomputer (MC1) and accepts the interrupt at any time. This entrance serves three interrupts. One is the start of the AF or FA operation, the second is the stop of the AF or FA operation, and the third is the operation of returning the focus adjustment state display immediately after the release and the operation in the continuous shooting mode. These 3
Let us describe two distinctions. The first and the second are distinguished by the input signal to the terminal (INT1). That is, AFS is used to start AF or FA operation as shown in Fig. 17 (A).
Signal falls from "High" to "Low", "Low" is 50μs
It is necessary to continue above. To stop the AF or FA operation, the AFS signal changes from "High" to "Low" as shown in Fig. 17 (B).
After falling to, within 50μs from "Low" to "High"
Need to get up to. A flag is used to distinguish the third operation from the first normal AF or FA operation. When a release interrupt described later comes, the release flag (release F) is set in the flow during release, and it is distinguished by checking whether or not this flag is set at the start of the next "INT1S". These will be sequentially described from # 8. # 8, INT at the start
Disable interrupts other than 1 and INT2. The event counter interrupt of INT3 and the internal interrupt of the timer that determines the blinking period of the display LED, which is not shown in the flowchart, are prohibited. # 9 is about to clear the used flag, but AFSINR from # 15
Among them, the two flags used as the previous states, that is, the scan prohibition flag (scan prohibition F in Table 5-1) and the previous low control flag (previous low control F in Table 5-1) are not cleared. The switch (S1) does not clear the scan prohibition flag even in continuous shooting mode.
As long as you do not turn off, once the contrast of the subject is sufficient for focus detection and you have been able to calculate the defocus amount, or once you have performed low contrast scan, as in the single shooting mode, This flag is left to prevent low contrast scanning. In addition, the reason why the low contrast flag is not cleared last time is "AFSINR" which is the interrupt flow by the AFS signal after release starting from # 15. If the switch (S1) remains on after release, The focus detection calculation result display is not cleared in order to restore it. That is, during release, the LED defocus direction display is turned off once, and when the release operation is finished, it is displayed again.Therefore, it is necessary to determine whether the LED was blinking at low contrast. Leave the flag.

Wait for 50μs time at the next # 10 and see if the interrupt that entered "INT1S" was an AF or FA stop interrupt.
I will go to see it. Here, the pin of the AF microcomputer (MC1) (INT
If the signal in 1) is as shown in Fig. 17 (A), A
Since the FS signal is "Low", proceed to # 12. If the signal is as shown in FIG. 17 (B), the AFS signal becomes "High" and proceed to the stop mode processing flow "STPMD" of # 2. The operation of the AF microcomputer (MC1) stops. In # 12, AFS after release
Interruption flow by signal Go to "AFSINR" or first AF
Distinguish whether it is due to an S signal interrupt. That is, if the release flag (release F) is on, # 15 “AF
SINR "and if the release flag (release F) is not on, proceed to the next Step # 13. In # 13, each terminal of the AF microcomputer (MC1) is initialized. That is, only the auxiliary light emitting terminal (P13) in the auxiliary light AF mode is set to "Low" and the other terminals are set to "High". However A
When the F microcomputer (MC1) has been in the stop mode so far and has come to this step at interrupt start, each pin remains in the same state, that is, only the pin (P13) is "Low" and the others It remains “High”.

Next, in # 14, the scan prohibition flag and the previous low control flag which were not cleared in # 9 are cleared again.
In # 401, the drive flag is cleared after the release. This flag is a flag used in the continuous shooting mode, and is used in the focusing processing flow to determine whether the state is the state before the release or the state after the release in the continuous shooting mode. #
This flag is cleared because 401 is the place to pass in the state before release. And then # 33 "AF STAR
Go to "T". After that, the focus adjustment state is detected, the lens is driven according to the result, and the focus adjustment state is displayed.
What is the focus adjustment status display? LED for display (LEDL) (LEDM) (LED
R) input signal LL and LR are “High”, LM is “Low” and green
This is to turn on the LED. If you see this display and close the switch (S2), or if you close the switches (S1) and (S2), the automatic focus adjustment is performed and the focusing operation is completed. For example, the control microcomputer (MC2) starts the release operation,
At the same time, an interrupt signal INREL is output to the AF microcomputer (MC1) to inform the release. AF microcomputer (MC
Since 1) receives this at the pin (INT2), a release interrupt occurs. This is the flow starting from "INT2S" in # 27 of FIG.

In # 27, interrupts other than INT1 and INT2 are first disabled. Next, at # 28, the signal from the terminal (ST4) is set to "Low" to turn off the auxiliary light illumination. This is a step that is necessary only in the release priority mode and not necessary in the AF priority mode.
This is because the focus adjustment is completed in the AF priority mode and the auxiliary light illumination is already off. # 29
Similarly, this is a step of stopping the lens motor (MO1) required only in the release priority mode. The motor (MO1) is not braked here. In the release priority mode, it is not always possible to release after the subject is in focus, and it is possible that the release may occur before that, so it was released while the lens was moving toward the in-focus position. At that time, the motor (MO1) with its non-focus point
Rather than apply a brake to stop the lens and release it, you can take a better picture by stopping without applying the brake, moving the lens by some inertia, and releasing it near the in-focus position. This is because there are many cases. In # 30, the focus adjustment status display or defocus direction display disappears. This is because the mirror is raised and the inside of the viewfinder is completely black during the release with the single-lens reflex camera. This is because it is meaningless to display only the display here, and it is not preferable that unnecessary light is output inside the camera during film exposure.

Next, at # 31, set the release flag (release F) to "1",
The release is left as a flag. The rest is # 32
Then, wait for INT1 or INT2 interrupt. When the release interrupt comes in succession, it starts again from "INT2S" of # 27. This occurs when the switch (S2) is repeatedly opened and closed while the switch (S1) in Fig. 2 is closed, and this is the case where the lens is fixed at the in-focus position without being driven.
It is the same as repeating the release in the locked state. After the switch (S2) is closed and released, the switch (S1) remains closed, and the control microcomputer (MC2)
As shown in the flowchart, the AFS signal enters the AF microcomputer (MC1) again and INT1 interrupt occurs. Then,
Since the release flag (release F) is set to 1 this time, the flow from # 8 "INT1S" proceeds to # 15 "AFSINR" in FIG. The steps from # 15 will be described later.

Next, when the switch (S2) is closed and released, and then the switches (S2) and (S1) are both opened as shown in the flow of FIG. ) AFS signal for stop enters into the AF microcomputer (MC1) and INT1 interrupt occurs. After that, the AF microcomputer (MC1) enters the stop mode by the above-mentioned flow and waits for the next interrupt again.

Here, the flow of interrupt start by the AFS signal after release will be described. The entrance is "INT1S" in # 8 in Figure 7.
However, since the release flag RLF is 1 this time, branch at # 12 and proceed to "AFSINR" at # 15. Here, first, the release flag (release F) is reset because this flow has been passed. In # 402, the drive flag is set after release because it is a place to pass in the case of the state after release. It will be used later in the focusing processing flow. Next, in # 16, input serial data from the control microcomputer (MC2). The serial data is input here to check whether the operation mode of the AF microcomputer (MC1) has been changed. The flow that comes to "AFSINR" starting from # 15 is the flow that comes after the release, but during this release or just before that, the operation mode, that is, each mode of AF mode / FA mode / MANUAL mode, also AF mode However, if the single shooting mode / continuous shooting mode is switched, the operation must be changed according to the mode. # 16 is a step for inputting the information of this mode from the control microcomputer (MC2). This # 16
Is a subroutine that starts from # 241 in Fig. 15 "SIOSE
Flow through T ”. Here, each mode is checked and the mode flag is operated. First, in # 241, the DTRQ signal of the terminal (P11) is set to "Low" toward the control microcomputer (MC2) to request serial data. Then, the control microcomputer (MC2) sees the DTRQ signal and sends serial data as shown in Table 4. # 2 on the AF microcomputer (MC1) side
Input this serial data at 42, and set the DTRQ signal to "High" at # 243. Data sent by serial communication are AF open F value AFAV0, lens drive defocus amount-pulse count conversion coefficient KROM, auxiliary light AF correction data ΔIR, lens drive inversion backlash correction data BKLSH, Auxiliary light OK signal AFFL, flash charge completion signal RDY, continuous shooting / single shooting mode signal DR, lens signal AFC with AF coupler shaft, FA enable / disable signal FAEN. When each information is sent by serial communication, the AF microcomputer (MC
It is saved in the RAM of 1), and the contents of that RAM will be referred to when necessary. The use of each information will be described later in the explanation of the flowchart.

From # 244, check each mode. In step # 244, the AF open F value AFAV0 is checked. The light receiving element for focus detection has a usable limit, and when the open F value of the lens is small, the incident light to the light receiving element for focus detection is eclipsed by the exit pupil, and correct focus detection calculation cannot be performed. Even if a single lens that makes focus detection impossible is not created, the focus detection limit F value may be exceeded depending on the combination of converter lenses and the like. For example, if the focus detection limit F value of the focus detection light receiving element is 7.0, a lens with an open F value of 5.6 for AF can detect focus, but if a double teleconverter is attached to this, the F value will be 11.2 and focus detection will be impossible. It means that Here, the AF open F value is the F value when the diaphragm of the lens is not closed, but even in the case of a lens whose F value changes due to zooming or focusing, the light receiving element for focus detection is not cut off. Since this is information for determining that, if the F value changes due to zooming or focusing, the smallest open F value is included. If the open F value AFAV0 for AF is larger than 7.0 in # 244, proceed to # 251, set the AF mode flag (AF.F in Table 5-1) to "1", and then in # 250. F
Also set the A mode flag (FA.F in Table 5-1) to "1" and MANUA
Set the flag state that it is in the L mode, # 16 in FIG.
Go back. F for open F value AFAV0 for AF is less than 7.0
Regarding the value, it is a lens that can detect focus # 245
Go to.

In # 245, it is checked whether it was in AF mode so far. If the AF mode flag is "0"
If it is "1", it means that it was not in AF mode and it is checked whether it is FA mode or MANUAL mode. # 246 is a step to check if there is an AF coupler axis. If the AFC signal is 1 ", there is an axis, so proceed in AF mode as it is, and if it is" 0 ", there is no axis, so automatic focus adjustment cannot be done. # 247
Go to and set "1" to the AF mode flag. The AF coupler shaft is a shaft for transmitting power from the motor (MO1) in the camera body to the focusing mechanism of the lens.

In # 248 of Fig. 15, it is checked whether or not the lens can detect the focus. If the focus can be detected, the FA flag (FA.F) is set to "0" to enter the FA mode. If the focus cannot be detected, the FA flag is set to "1". Then, it is judged that the AF flag is "1" and the mode is MANUAL mode. When FAEN = 1, it means that the lens is attached to the camera body and the focus can be detected. Other than this, FAEN is “0”. A lens whose focus cannot be detected is a lens such as a reflective telephoto lens whose focus cannot be detected even if the open F value for AF is small, or a special lens such as a shift lens or a vari-soft lens in which aberration becomes extremely large. This subroutine does not see the change from FA mode to AF mode, but this will be seen later in step # 86 in FIG.

Now, the subroutine of FIG. 15 returns and proceeds to the next step # 17. Check if it is AF mode. If it is AF mode, go to # 19. If it is not AF mode, go to # 18.
Check whether FA mode or not, and if not FA mode, go to the # 36 "MANUAL" flow.

In # 19, if the state before release is low contrast when looking at the previous state for display restoration, the low contrast display is restored in # 20. The low contrast display is a display in which both ends (LEDL) (LEDR) of the three LEDs (LEDL) (LEDM) (LEDR) for focus adjustment state display are blinked by repeatedly turning on and off at 2 Hz. If the contrast is not low, the focus adjustment state or the direction display is restored in # 21. The contents displayed before the release are saved in the display register, so the previous display is restored when the port is set to output mode. In # 22, by the AF mode flag (AF.F)
Check if it is in AF mode, FA not in AF mode
If there is a mode, go to # 39 “CDINTA” to repeatedly perform focus detection. Therefore, in the FA mode, if the switch (S1) in FIG. 2 is turned on after the release, the focus is continuously detected and displayed. In AF mode, # 23 is used to check if the single shooting mode is continuous shooting mode based on the DR signal. If DR = 0, it is single shooting mode, and in # 25, the AFE signal of the terminal (P12) is set to “Hi”.
gh ". This signal is for notifying the control microcomputer (MC2) of the information that the automatic focus adjustment operation is completed and the focus is achieved and the release is possible.

When the shutter release button is pressed down to the second step, the control microcomputer (MC2) permits the release if it is "High" when it sees this signal in the AF priority mode and "Lo".
If it is w ", the release is not possible. That is, in single shooting mode, after focusing and releasing once, press the release button one step (switch (S1) is ON), AF
If an interrupt such as the S signal does not come in, “AFSIN from # 15
Since the AFE signal goes to "High" at # 25 following the flow of "R", if the position of the subject is changed as it is, the shutter can be released even in the out-of-focus state. At this time, the lens is not driven because it is waiting for the release interrupt or the AF microcomputer (MC1) stop interrupt at the next # 26. This sequence can be called "AF lock".

On the other hand, in the continuous shooting mode, the process proceeds from # 23 to # 24. In # 24, clear the auxiliary light mode flag and start "CDINTA" from # 39.
Proceed to and enter the next focus detection. In other words, the auxiliary light AF mode also enables continuous shooting mode. In this case, once the normal light mode is restored without entering the auxiliary light mode from the beginning, the auxiliary light mode is entered again when the conditions for the auxiliary light mode are met. I am trying. This is because it may be unnecessary for the subject to enter the auxiliary light mode when the subject becomes bright.

The flow starting from “AF START” in # 33 of FIG. 9 starts from # 14. In # 33, the subroutine “SIOSE in FIG. 15 is displayed.
Calling "T". When starting the operation of the AF microcomputer (MC1), the control microcomputer (MC2) receives various data to determine the operation mode. The mode decided at this time is
It is automatically written to the mode register RG in the AF microcomputer (MC1). This register RG is for checking whether the mode has been changed later. In # 34 and # 35, the operation mode is checked, and if it is neither AF mode nor FA mode but MANUAL mode, proceed to # 36. # 36
Then, when it comes from another person, all the signals MR, MF and MB to the driver circuit (MDR1) are set to "High" to stop the lens motor (MO1). In # 37, interrupts other than INT1 and INT2 are stopped, and it loops to # 33 and repeats.

When in AF or FA mode, proceed to # 38 to initialize the CCD image sensor (FLM) and warm up the sensor. The interface circuit (IF1) is set to A by setting the IOS signal of the terminal (P20) to “Low” in # 39.
This is also to set the mode to input the signal from the F microcomputer (MC1) and to set the mode to integrate the output of the CCD image sensor (FLM). And the first
Go to # 44 in Figure 10. Here, first, the 1-cut shot flag (1-cut shotF in Table 5-1), that is, the integration time is 5
Clear the flag that indicates whether it has exceeded 0 ms.
In # 45, set the AFE signal output from the terminal (P12) to "Low". I'm doing this here because it keeps looping even after focusing. This is because if the AFE signal is in focus, "Hig
Since it is a signal that becomes "h", it is set to "Low" in preparation for the next calculation. Next, at # 46, the NB2 signal is output from the terminal (P23) and the integration of the CCD image sensor (FLM) is started. To do.
In # 47, the lens drive pulse count value EVTCNT for correcting the lens movement amount during focus detection calculation and integration described later is read and stored in the memory T1. At # 48, half of the maximum integration time of the CCD image sensor (FLM), 100ms, is set to 50ms. In Fig. 9, there is "CDINT" starting from # 40 in parallel with "CDINTA", and there is another flow up to # 53,
This is a flow for the function called "convolution integration", and a description thereof will be given later.

Continue from # 48 to "TLNTφ" from # 55. # 55 allows all interrupt routines. In # 56, check the NB4 signal coming into the terminal (P25), and
If it is w ", it is a signal that the CCD image sensor (FLM) has finished the integration according to the brightness of the subject, so the flow proceeds to" CDINT2 "of # 64. If it is "High", it means that the integration is continuing, so proceed to # 57 and check whether the maximum integration time initially set has elapsed. That is, # 48
See if 50ms set in step # 40, 40ms set in # 53, 50ms in # 61 or 150ms in # 62 have passed, and if not, go back to # 56 and repeat the loop Maximum integration If time passes, proceed to # 58. 1-cut shot here
If the flag (1-cut shotF) is not "1", proceed to # 59 and set "1" to this flag. 1-cut sh when going to # 63
Since the ot flag is "1", it is after passing # 59 or # 49. In # 60, check if the 200ms flag (200msF in Table 5-2) is "1",
If it is not "1", the maximum integration time is usually set to 100ms, so the remaining 50ms of the integration 50ms set in # 48 is set in # 61 and the process returns to # 56 to check the NB4 signal. # 60 in 2
When the 00ms flag is "1" (this is set in the later flow and only under special conditions, the maximum integration time is set to 200ms), the integration of 50ms set in # 48 Set the remaining 150ms and return to # 56 to check the NB4 signal.

If the output from the CCD image sensor (FLM) is obtained to a sufficient level, proceed from # 56 to # 64. Even if the output is not sufficient here, the integration must be terminated if the maximum integration time has passed, and that is the time when the process proceeds from # 58 to # 63. # 58
Then the 1-cut shot flag is "1" this time, so be sure to #
Proceed to 63, and from the terminal (P21) to the interface circuit (IF
Output the forced integration stop signal NB0 to 1). Then proceed to "CDINT2" from # 64. The steps from # 64 to # 67 are the flow of "renormalization integration", and the explanation is given later.

In # 68, interrupts other than INT1 and INT2 are prohibited,
This is to prevent interruption of timing when the data is taken in after this and timing is not wrong. Since INT1 and INT2 interrupts start from the beginning of the main flow, do not disable them. # 69 has previously turned off the ST4 signal at the terminal (P13) when the auxiliary light LED (48) was on during CCD integration. # 70 is the pin (P20) IOS
The signal is set to "High" and the interface circuit (IE1) is switched to the data output mode. That is, the signals of NB4 to NB0 become lines for data transfer, and data can be sent from the interface circuit (IF1) to the AF microcomputer (MC1). Although 8-bit data is sent as data, it is sent in two steps in 4-bit parallel from NB3 to NB0, and the timing is taken by NB4 and NB4 sends "Hig
The upper 4 bits of data are sent when "h" and the lower 4 bits of data when NB4 is "Low". AF microcomputer (MC1)
Recreates and sends the data sent separately to the upper and lower layers.

Therefore, first, the AGC data sent from the interface circuit (IF1) to the AF microcomputer (MC1) is shown in FIG.
Any of the numerical values (1 times, 2 times, 4 times or 8 times) of the gain determined in the AGC controller (406) (hereinafter,
AGC data) is sent, and this is AFed at # 71 in Fig. 10.
Take it into the microcomputer (MC1). By the way, after the integration of the CCD image sensor (FLM) is completed, the timing at which these data come out is determined by the interface circuit (IF1), and the AGC data must be taken in immediately after the integration is completed. AGC data is output for a certain period of time, and as soon as this is completed, pixel data of the CCD image sensor (FLM) is also sent at a certain timing. Just 72 hours after capturing this AGC data, # 72
As described in, the lens drive pulse count value EVTCNT at the end of integration is read and stored in the memory T2. It corresponds to # 47 at the start of integration.

Immediately after this, the pixel data of the CCD image sensor (FLM) is input at # 73 and saved in the memory of the AF microcomputer (MC1). The next # 74 is a subroutine that checks whether the lens being driven hits the infinity end or the closest end while driving the lens, and if it hits the end (infinity end or the closest end), the lens drive motor. (MO
1) Stop or reverse drive. The subroutine "CKLOCK" will be described later with reference to FIG. In # 75, the data for driving the lens etc. is obtained by serial communication with the control microcomputer (MC2). Even though I got the data once in # 33, I am doing serial communication again here because it does not pass through # 33 in the repeated loop, so if the conversion coefficient KROM for lens drive changes in the middle (depending on the lens The data changes when the microcomputer operation mode changes, etc.), so to see this repeatedly #
There is a "SIOSET" on the 75. Then, in # 76, the focus detection calculation is performed using the data of the CCD image sensor (FLM) imported in # 73. With respect to this method, the defocus amount DF is obtained by the method already proposed by the present applicant in Japanese Patent Application Laid-Open No. 59-126517.

From # 77 to # 85, whether or not the brightness of the subject is lower than a predetermined level is checked to judge by looking at the level of AGC data. Here, when the brightness of the subject is below a predetermined level, it is called low light. In # 77, "1" is set in the low light flag (low light F in Table 5-2). In # 78, if the electronic flash device is attached to the camera and the auxiliary light switch (44) is closed, the AFFL signal sent by serial communication is "1", so proceed to # 80. .. That is, if the auxiliary light emission enabled state is set, the AGC data is doubled and 4 times when the maximum integration time is 100 ms.
When it is double or 8 times, it becomes a low light judgment and # 86 “MAIN
If the AGC data is 1x, clear the low light flag to "0" at # 85 through # 80 and proceed to # 86. In the mode with the maximum integration time of 200ms, all become low light and go from # 80 to # 86.

On the other hand, if the auxiliary light emission enabled state is not set, the process moves from # 78 to # 81. In the mode with the maximum integration time of 100 ms, when the AGC data is 4 times and 8 times, # 82, # 83, # 8
It becomes low light judgment through 6 and AGC data is 1 and 2
At the time of double, it moves from # 82 or # 83 to # 85 and clears the low light flag and goes to # 86. Maximum integration time is 200 ms
In the case of the mode, when the AGC data is 2 times, 4 times, or 8 times, the low light judgment is made by going from # 84 to # 86, and when the AGC data is 1 time, going from # 84 to # 85 is done # 85 Clear the low light flag and go to # 86. Here, the determination of low light when the auxiliary light emission enabled state is set is 1 more than the determination of low light when not set.
It starts from a bright place. This is because if the subject has low contrast and low brightness, focus detection calculation is impossible,
It is very effective when giving up automatic focusing. That is, if the auxiliary light emission enabled state is set, the focus detection in the auxiliary light non-use state is given up early, and the auxiliary light emission enabled state is entered immediately to immediately detect the focus. If is not set, the focus is detected only by outside light to the place where you can go anyway,
If the contrast becomes low and the brightness becomes low, the lens is retracted without automatic focus adjustment. In this embodiment, before giving up the focus detection, the lens is further extended or reciprocated to perform one reciprocating scan to search for a position having contrast. This will be described in the flow after "LOWCON" from # 165 in FIG.

In the present embodiment, the determination of the subject brightness is based on AGC data, but this may be based on the integration time. For example, among the flags used in this embodiment, the CCD image sensor (F
If the integration time of LM) is 50 ms or more, it will be 1-cut shot
You may use a flag.

Now, the "MAIN1" from # 86 in FIG. 11 will be described below, but from here, the process of driving the lens will be explained. First #
The 86 compares the serial data obtained in # 75 with the mode in which the AF microcomputer (MC1) was operating so far, and if the mode has changed, restarts from "AF START" in # 33.
That is, it is set after the last serial communication # 33.
Contents of register RG indicating AF mode / FA mode / MANUAL mode, single shooting / continuous shooting mode, focus detection mode flags (AF mode flag, FA mode flag), single shooting mode flag Compared with (DR), if it has changed # 33
Is to proceed to. Then, at # 33, a new mode is automatically written in the mode register RG. In # 87, it is checked whether or not the mode is the focus detection operation mode using the auxiliary light. If it is the mode using the auxiliary light (hereinafter referred to as the auxiliary light AF mode), the focus of the auxiliary light in FIG. 14 is used. Detection flow # 238 "LSAVE"
Go in. How to enter this auxiliary light AF mode
Since the condition is that the subject has low contrast and low brightness, the flow starts from the low contrast flow starting from “LOWCON” in # 165 of FIG.

If it is not the auxiliary light AF mode in # 87, the current low contrast flag (current low contrast F in Table 5-1) is checked in # 88 to determine whether or not the result of focus detection calculation is low contrast. If so, move to the "LOWCON" flow of # 165 in FIG. This time the low contrast flag that appears in # 88 is determined and set in # 76. If the result of this operation is not low contrast, #
Proceed to 89, check the AGC mode input in # 71 of FIG. 10, and if the AGC data is 1 time, clear the 200 ms flag in # 90. This is the maximum integration time when it was dark
I mentioned that there is a state of 200ms mode, but when it is in 200ms mode, if the AGC data is 1 time, it is not necessary to set it to 200ms mode. It is better to set it to 100ms mode with a shorter maximum integration time. This is because the time is short. When integration time is 200ms and AGC data is 1 time, integration time is 100m
It can be seen that the pixel output is almost the same as when the AGC data is doubled in s, and it is disadvantageous when the integration time becomes long, considering the movement of the subject and camera shake. If you can find the contrast of the subject,
The maximum integration time is 100ms.

The flow of "NLOC1" starting from # 91 is a flow when the contrast is found in the subject, and in # 91, the scan prohibition flag is set to "1". This is because if the contrast of the subject is low, look for a high contrast position,
Detecting the focus while moving the focusing lens is called low contrast scan, but once the contrast appears on the subject, this low contrast scan is performed in a series of sequences while the switch (S1) is closed. Is prohibited. This is because, if you scan frequently, it will be difficult to use as an autofocus camera, and the contrast will be found once. However, it seems that there is a high probability that the contrast will be found again, and even if the low contrast is reached next time, if the low contrast scan is started immediately, it is counterproductive to the focus detection.

Further, the reason why the scan is prohibited is that, in addition to this, there is a case where the scan is once completed with low contrast. The flow from # 92 to # 101 mainly shows the processing when a sufficient contrast is found during the low contrast scan. There are two main cases, which are divided into when the CCD image sensor (FLM) integration time exceeds 50 ms and when it does not. When the subject is dark such that the integration time exceeds 50 ms, when the contrast is found during low contrast scanning,
Once the lens is completely stopped, focus detection is performed again, and the lens is moved to the in-focus position according to the result. Focus is not detected while the lens is moving. The reason is that when the lens is driven when the integration time becomes long, the image of the subject flows out, which adversely affects the defocus amount calculation. Integration time becomes longer, and AG
This is because when the magnification of C becomes large, the noise due to the dark output variation of the CCD image sensor (FLM) also becomes large, and if the image flows in this state, delicate focusing will be lost.

Therefore, when the integration time exceeds 50 ms, the focus is not detected while moving the lens, and the focus is detected by the value only when the lens is stopped. This is called the 1-cut shot mode. A flag indicating that (1-cut shot flag in Table 5-1) is provided. This flag is already set in # 49 or # 59. Next, in the case of a bright subject whose integration time does not exceed 50 ms, if sufficient contrast is found during low-con scanning, then the focus detection is performed using that contrasted data without stopping the lens. The calculation is performed, and the lens is driven up to the resulting focal point. During this period, the focus detection calculation is repeated, and the lens drive amount up to the in-focus position is constantly refreshed for focusing. This is called the multi shot mode because the focus is repeatedly detected while the lens is being driven. When it comes to focus detection without stopping the lens during low contrast scanning, the lens position is different between the time when the CCD image sensor (FLM) is integrated and the time when the lens drive amount is obtained. For the preparation for correcting this movement, see “LO
It is performed in the "WCON" flow, and the movement amount is corrected using this. The idea about this movement correction is
Since it is described in Japanese Patent Laid-Open No. 59-68713, detailed description will be omitted here.

Next, find the contrast in the low contrast scan,
It is possible that low-contrast results may be obtained even after the operation of the multi shot mode is started. In this case, the result of low contrast is ignored, and the lens is driven to a position that is considered to be the in-focus point according to the drive amount set before the low contrast is obtained. Only the results with contrast are used for driving. The decision to exit the low contrast state is made by checking the previous low contrast flag (previous low contrast F in Table 5-2). This flag is set in the "LOWCON" flow from # 165 of FIG. 13, and is set when the previous calculation result was low contrast. On the other hand, when it comes to # 92, it means that there was contrast in this result, so # 92
Then, if the low contrast flag was set to "1" last time, it means that the low contrast was exited and the process proceeds to # 93. If the low contrast flag was “0” the last time, there is contrast from the beginning and it is passed as # 92 when the focus is detected.
To # 102. In # 93, the focus adjustment status display is turned off. Until now, when the lens drive was in a low contrast state and the lens drive was stopped, a blinking display indicating that focus detection is not possible is displayed, but this is erased because the contrast appears. In # 94, if the 1-cut shot flag is set as described above, the lens must be stopped, so proceed to # 95. If the 1-cut shot flag is not set, the lens is stopped even during low-con scan. Do not stop, # 101
Go to. In # 101, the previous low contrast flag, the per-scan flag (F per scan in Table 5-1) and the in-scan flag (In-scan F in Table 5-1) are cleared. This is after finishing low contrast scan,
Alternatively, it is for resetting the flag indicating the state when the scan is in progress. Of course, the scan prohibition flag is left without being reset.

# 95 comes when it is in the 1-cut shot mode state. Here, it is checked whether or not it came during the low-con scanning by checking the scanning flag. If it is not scanning, proceed to # 101, go to the one that drives the lens according to the current calculation result, and if it is scanning, # 96, #
At 97, the lens drive motor (MO1) is de-energized and the brake is applied according to the signal pattern shown in Table 6. In order to remember the state where the lens is stopped, the driving flag (driving F in Table 5-2) in # 98 is cleared. At # 99, wait 70ms until the lens is completely stopped. At # 100, clear the same flag as # 101 and return to "CDINTA" at # 39 to start the next focus detection. As described above, the # 99 wait time causes an image to flow if the lens is moving when the integration time of the sensor is long, and the problem is that even if the movement data is corrected to the integration data position during driving, Correct correction is difficult when a negative acceleration is applied, and if the next sensor integration is started after the lens is completely stopped, the focus shift of the focus detection calculation can be prevented.

Next, the flow for converting the defocus amount of the focus detection calculation result into the pulse count value for driving the lens "MPUL
There is an S ". In # 102, the defocus range in which the lens is in focus within this range is set in the register FZW as the focusing zone. Note that here, the focus zone amount in the automatic focus adjustment state (AF mode) and the focus zone amount in the focus adjustment display state (FA mode) are distinguished,
Set a wider value in FA mode than in AF mode. # 103
Since # 106 is the flow when the lens is stopped at the end, this is the case when the lens is hitting the end at infinity. The end flag of # 103 (end F in Table 5-2) is
It is made in the termination check subroutine before coming here. If the lens has stopped at the end, the process proceeds to step # 104, and the direction flag (previous direction F in Table 5-3) is checked to see in which direction the lens is about to move. If the lens is at the infinity end and you are trying to drive to the infinity side, proceed to # 105 to check the end position flag (end position F in Table 5-2) to see if the end position is at the infinity end side. Looking at the closest end side, if it is at the infinity end side, proceed to # 106 and set the focusing zone to a large value of 255 μm. If the lens stop position is the closest end, # 10
7 go through. This variation in focus detection data may result in the in-focus position being further toward the infinity end even if the lens is at the infinity end position, and if a narrow focusing zone is set, Even at the infinity end, there is the possibility of trying to move the lens further to the infinity side. Further, it is possible that the position considered as the end at infinity is actually stopped by the lens due to other external stress. In the present example, this is indistinguishable.

Therefore, when the detection result shows that the lens is at the infinity end and the in-focus position is beyond the infinity end,
First, widen the focus zone to 255 μm, and if the lens is in the focus zone, the focus is displayed. If this value is not in the focus zone, focus detection is not possible (LED blinks) Display). If the lens is forcibly stopped by hand while the lens is trying to move to the infinity side during automatic focus adjustment, the LED will blink if the lens stop position is not within the focus zone. That is. The flow of this display is from # 120 to # 123.

On the other hand, if there is a lens at the closest end and it is detected that the subject is on the close side, or the lens is trying to move to the close side during automatic focus adjustment, the lens is forcibly stopped halfway. If the position is not within the in-focus zone, the display is made in the closest direction. The flow of this display is from # 147 to # 152 in FIG.
Hit If the lens does not stop at the infinity end, the focus zone moves to # 107 with the value set in # 102.

In # 107, it is checked based on the fill light mode flag whether or not the fill light AF mode is set, and if it is the fill light AF mode, chromatic aberration correction is performed. Since the infrared light is used as the illumination light in the auxiliary light AF mode, the best focus position is displaced due to the difference in the light source during flash photography. Therefore, if the auxiliary light AF mode is set, this focus position shift amount must be corrected. As shown in Table 4, the correction data ΔIR according to this taking lens is based on the control microcomputer (MC
It is sent from 2) by serial communication. This is corrected in # 108 with respect to the defocus amount DF that has been obtained so far. However, the correction data ΔIR is prepared assuming that auxiliary light of a certain wavelength, for example, a light source of 800 nm is used. However, if the auxiliary light that is actually used is, for example, a 700 nm light source, it will be overcorrected. Therefore 8
In order to convert the correction value of 00 nm to the correction value of 700 nm, the correction value is halved. However, this is a condition when the surrounding brightness is dark, and considering the usage conditions of the focus detection device used now, the surrounding brightness is often slightly dark. Therefore, if the correction value is halved, the correction will still be overcorrected. Therefore, the optimum magnification for the apparatus of this embodiment is 1/4. Therefore, in # 300, ΔIR is multiplied by 1/4 and put in ΔIR again, and this value is used for correction. The correction formula can be expressed as follows.

DF = DF ₀ −ΔIR DF ₀ is the defocus amount in the auxiliary light mode, and DF ₁ is the corrected defocus amount.

Then, in # 109, the defocus amount is converted into a pulse count value for driving the lens. Since the coefficient for this conversion is also unique to each lens, the data KROM sent by serial communication is used like ΔIR. The defocus amount DF found is also multiplied by the conversion coefficient KROM to find the pulse count value DRCNT for driving the lens. Similarly, the focusing zone FZW is also multiplied by the data KROM and converted into the pulse count value FZC. The conversion into these pulse count values is described in detail in Japanese Patent Laid-Open No. 59-140408, and therefore omitted here.

Then, in # 110, it is determined based on the driving flag (driving F in Table 5-2) whether or not the automatic focus adjustment operation is currently being performed, and when the lens is driving, "IDOBU" in # 131 is set.
Branch to N ”. When the lens was stopped, that is,
When passing through the flow for the first time, when confirming the in-focus position after completion of automatic focus adjustment, or when in FA mode, proceed to # 111. Here, the defocus amount DF when the lens is stopped is stored in the memory FERM.
Save to. This value will be used later to determine whether to go to the loop for checking the in-focus position after the end of automatic focus adjustment or not according to this value. In the next step # 112, it is determined whether or not the FA mode is set based on the FA mode flag. If the FA mode is set, the flow branches to “FAP” from # 113. This is because the non-AF mode is the FA mode.

In # 113, it is judged whether or not the lens is in the focusing zone. Here, the lens drive pulse count value
Although DRCNT is compared with the focus zone pulse count value FZC, the defocus amount DF and the focus zone amount FZW may be compared. As a result, if there is a lens in the focusing zone,
The focus is displayed with # 115. This sets the LM signal of the terminal (P31) to "Low" and the LL and LR signals to "High",
This is done by turning on only the central LED (LEDM). If it is outside the focusing zone, the process proceeds to step # 114 where the direction in which the lens should be driven is shown. For example, when the lens is extended, set the LL signal of the terminal (P32) to "Low" to turn on the left LED (LEDL), and when the lens is extended, change the LR signal of the terminal (P30) to "L". "Low" and right side LED
Turn on (LEDR). And for the next focus detection,
Loop to # 40 "CDINTA" in the figure.

If it is in AF mode in # 112, focus check in AF mode is performed in # 116. Lens drive pulse count value DR
If the CNT is smaller than the focus zone pulse count value FZC, it means that the focus is achieved, and the process branches to “INFZ” from # 117. # 1
In 17, the focus display is displayed as in # 115 in FA mode, and
At 18, set the AFE signal from pin (P12) to "High". The control microcomputer (MC2) is watching this signal, and if it becomes "High", it is considered that the automatic focus adjustment has been completed. Then, in the AF priority mode, the release operation becomes possible only after the AFE signal becomes "High".

Next, in # 403, the SCF flag is checked. If the SCF flag is 0, it means the continuous AF mode, so the AF operation is continued even after focusing. Then proceed from # 403 to # 407. In # 407, it is determined whether or not the fill light mode is set, and if it is the fill light mode, the process proceeds to # 233 so that the fill light is continuously emitted. If it is not the auxiliary light mode, it is not necessary to emit light, so the process returns to step # 39 and the next focus detection is immediately started. If the SCF flag is 0, the one-shot AF mode is in effect, so AF lock is performed after focusing, so # 40 cannot proceed.
This AF lock means that once the subject is in focus, the focus display will stay on even if the focus position changes, and the lens will not be driven again.
As this processing, the loop of waiting for the interrupt of INT1 which is the AF stop instruction or the release interrupt of INT2 is executed in # 119. However, there is one exception here. The processing is # 404 to # 406. This is a problem in the continuous shooting mode, especially in the AF priority mode continuous shooting. When the camera is released after focusing, the camera automatically starts film winding operation.

On the other hand, AF often ends before the winding is completed. If the subject is in the focus zone, the focus is displayed again and the AF lock is activated. If the subject and the camera are relatively stationary, but they are moving, if the AF lock is fast and the winding is completed, and the release is possible, the subject will move out of the focus zone and become out of focus. Will be. Therefore, only in continuous shooting mode, continuous AF after focusing after release
As a mode treatment, it is looped to the next focus detection. However, this is the case in the normal mode and in the case of the fill light mode, the principle is followed. This auxiliary light mode discrimination is #
When it is 404 in fill light mode, it waits for an interrupt at # 119. # 405
Then, determine whether it is after the release or not, and if it is before the release, follow the principle in # 119. Then, in # 406, whether the continuous shooting or the single shooting is determined, and if the single shooting is performed, the signal DR is 0.
Go to and follow the principles. Since it is continuous shooting when DR is 1, loop to # 40 "CDINTA" at this time.

When it is determined that it is out of the focusing zone in # 116, # 120
Go to. As described above, here, the termination flag (the 5-2nd
It is the end by checking the end F) of the table (# 120), the previous position flag is checked and the focus position of the focus detection result is at the infinity end side (# 121), and the lens stop position is at the infinity end. If it is (# 122), proceed to # 123, do not drive the lens, blink both LEDs (LEDL) (LEDR) on both sides to indicate that focus detection is not possible, and wait for interrupt at # 119. , I will not go to the next focus detection. In cases other than these conditions, the process proceeds to # 124.

From # 124 to # 130, the reversal check of the defocus direction is performed. That is, by comparing the defocus direction of the previous focus detection calculation result with the direction of the result calculated by this loop, if it is found that the defocus direction is reversed, correct the backlash of the lens drive system. That is. In driving the lens,
In particular, a considerable amount of play is provided in the coupler portion of the driving force transmitting shaft between the camera body and the lens. Therefore, if the lens driving direction is reversed due to a change in the distance to the subject, the lens will not move to the in-focus position determined by the calculation result due to the amount of rotation from the motor (MO1). Therefore, if the direction is reversed, the amount of backlash must be corrected. This backlash amount is unique to the taking lens, and as shown in Table 4, the control microcomputer (MC2)
From serial communication. However, when the previous defocus direction that appears here is the first loop after closing the switch (S1), remember that this is also the last lens drive direction in the previous sequence. ing. That is, the memory is remembered even in the stop mode of the microcomputers (MC1) (MC2) before the switch (S1) is closed. Further, this backlash correction is not so right after the calculation result is reversed, but this correction is limited only when the lens is stopped. If the result is that the direction is reversed while driving the lens, just stop the lens and do not immediately perform the reverse driving of the lens. Also, the previous direction flag is not reset. Then, the direction obtained by the next focus detection calculation after stopping the lens (this is the current direction)
However, if it is reversed from the direction that was obtained once before the lens was stopped, that is, the direction that was driving the lens (previous direction), it means that the backlash will be corrected for the first time. This is because the dispersion of the calculation in the vicinity of the in-focus position is taken into consideration so that the lens does not hunt due to the error of the backlash amount.

The flow for these is # 124 to # 130, which will be described below, and # 134 in FIG. 12, which is the flow during lens driving.
Has been achieved in combination with # 140. In # 124, the current direction flag (current direction F in Table 5-3) is checked to see the current defocus direction, and in # 125 and # 126, the previous defocus direction is checked. If the defocus direction is different between the last time and this time, # 127,
Go to # 128 and rewrite the previous direction flag.
If they are in the same direction, skip to "TINNZ" in # 141. #
In 129, the backlash correction data BKLSH sent by serial communication is corrected with respect to the lens drive pulse count value DRCNT, and in # 130, the reverse flag is used to reverse and correct the backlash (Table 5-2). F) is set and the process proceeds to step # 141.

Next, with reference to FIG. 12, the flow "IDOBUN" from # 131 when the lens branched from # 110 is being driven will be described.
At # 131, check if the lens is hit at the end, and at # 132, read the event counter value EVTCNT for the third time to correct the movement amount and register it.
Store in T3. Now you have all the data for the correction of the movement. That is, T1 at the start of sensor integration, T2 at the end of integration, and T3 at the end of focus detection calculation, using these three values, focus detection calculation based on pixel data obtained by integration during lens driving. As a result, the amount by which the lens moves until the lens drive amount is set after the actual calculation is completed is corrected. When the moving amount Tx of the lens during integration is calculated by the pulse count value, Tx = T1
−T2. Since the event counter is a subtraction count here, T1> T2 and Tx is positive. The amount of lens movement Ty in the time required for focus detection calculation is Ty =
Calculated as T2-T3. Assuming that the lens is moving at a constant speed, the intermediate position of the sensor integration time is represented as the point where the subject data was obtained. Tz = Tx / 2 + Ty The lens has moved by the amount of. Therefore, if Tz is subtracted from the count value DRCNT obtained by the calculation result of this time, the movement amount is corrected. So, in # 133, D
RCNT-Tz is newly replaced as DRCNT, and the value is set as the next lens drive pulse count value.

Steps # 134 to # 140 are the flow when the defocus direction is reversed during lens driving as described above. In # 134, the current direction flag is checked to see the current defocus direction. Then, the previous direction flag is checked to check the previous defocus direction, and if the direction is reversed, proceed to # 137, and if not reversed, proceed to # 141. #
In 137 and # 138, the lens drive motor (MO1) is de-energized and the brake is applied to stop it. In # 139, the driving flag indicating that the lens is being driven is cleared, and in # 140, wait 70 ms until the lens stops. Then proceed to # 39 "CDINTA".

"TINNZ" starting from # 141 is a flow that merges from both during lens driving and during lens stopping, and is a part where the driving pulse count value DRCNT is set and the lens is moved. The driving speed of the lens is a two-stage type in this embodiment, and it is set to switch between high speed when the lens is far away from the focus position and low speed near the focus position of the lens. . The part that controls the lens at low speed is called the near zone. In # 141, the lens drive pulse count value DRCNT is
Check whether the pulse count value is NZC or less within this near zone area. If the lens is within the near zone area, proceed to # 143 and set the near zone flag (near zone F in Table 5-2). set. At # 144, the MC signal from the terminal (PO3) is set to "Low" to drive the lens drive motor (MO1) at low speed as shown in Table 6. On the other hand, when outside the near zone, #
Proceed to 142 to set the MC signal to "High" to drive the lens drive motor (MO1) at high speed.

Although a part of the description has been given in the above from # 145 to # 152, it is a flow of processing when the lens is stopped at the end position. By the way, detecting that the lens is stopped at the end does not mean that there is a switch at the lens end position, as described in the subroutine from "CLOCK" in Fig. 14 described later, but instead of the interrupt port INT3. Based on the judgment that the lens is stopped when the pulse from the motor drive amount monitor encoder (ENC) input from is not input for a certain period. Even if the lens is stopped even though the motor (MO1) is being driven, it is judged that the lens is hit at the end of the lens, so the motor drive is stopped and the end flag is set in the "CLOCK" subroutine. To build. With this method, even if the lens is not at the end, it will be forcibly stopped in the middle, or something will be caught in the lens, or the lens will stop for a moment (on the order of several 100 ms). However, it will be judged as the end.

In order to prevent such a thing, even if you see that the lens stopped at the end, try moving the lens again, and only after it is judged as the end by the "CLOCK" subroutine,
It is said that it actually stops at the end. The flag to see this is the end 2nd flag (end 2F of Table 5-2), and # 145
Then, look at the end flag created in the "CLOCK" subroutine, and when it is "1", look at this end 2nd flag in # 146. In the initial state, this flag is "0", so proceed to # 150, set the 2nd end flag,
The lens drive flow from 153 moves the lens. Then, when it comes to # 146 in the next loop, it is judged that the vehicle has stopped at the end for the first time, and the process proceeds to # 147.

In # 147, the current defocus direction is checked, and in # 148 and # 149, the end position flag is checked to see which side the lens is currently hitting. That is, assuming that the current defocus state is the front focus (current direction flag = 1) and the lens position is at the infinity end,
The lens will have to be moved further to the infinity side than the current infinity end. In this case, the process proceeds from # 148 to # 40, and in the next loop from "CDINT", the focusing zone is expanded and the focusing recheck is performed as described above.

This time the defocus state is the rear pin (this time direction flag =
0), and if the lens position is the closest side (end position flag = 1) in # 149, the lens has to be moved closer. In this case, # 149
To # 152, set the LL signal from the terminal (P32) to "Low" and turn on the direction display instructing to move the lens to the closest side. Then leave the lens stopped and #
Go to the next loop from 40 and repeat focus detection. And if the position of the subject changes and the defocus direction reverses,
During the loop, the process proceeds from # 147 to # 148, exits to # 151, clears the end flag, and enters the lens driving loop from # 153. In this embodiment, the current direction flag is used for checking the defocus direction of # 147, but the previous direction flag may be used. In this case, the lens is moved from the state where the subject is closer to the lens than the closest end. The lens does not follow and remains stopped even if it enters the focusable area of. In the case of one-shot AF mode, the latter method may be used, and in the case of continuous AF mode, it may be inconvenient unless the former.

In this latter case, once the low contrast state is reached, the termination flag is cleared in the "LOWCON" flow of # 165 in Fig. 13, so the lens exits from the closest edge and enters the lens drive state again. Entering, it means that automatic focus adjustment is possible. Next, if the lens is not at the end or if it is at the end but is about to move in the opposite direction, the lens drive flow from # 153 in FIG. 12 is entered. In # 153, all focus adjustment status display LEDs are turned off. This is based on the basic principle that the defocus direction is not displayed while the lens is being driven. When the lens is stopped and the lens is in focus, the center LED (LEDM) is lit to show the focus, and either the LED (LEDL) (LEDR) is lit to display the defocus at the closest end or the infinity end. The focus direction is displayed, and the LED (LEDL) (LEDR) blinks when the contrast is low. In # 154, the lens drive pulse count value DRCNT is set in the event counter EVTCNT and the termination check register MECNT. Value DR set in event counter EVTCNT
When a pulse from the encoder (ENC) enters the interrupt terminal (INT3) and the AF microcomputer (MC1) is interrupted, CNT is subtracted in this interrupt flow (INT3S in Fig. 16). The mechanism is that if the lens is stopped when the count value DRCNT reaches “0”, the image is in focus.

In # 155, the lens driving motor (MO1) is energized to start lens driving. This moves the lens according to the previous direction flag. That is, this flag remains as the lens driving direction so far. Because the previous direction flag, when the lens is stopped,
This is because the content from the current direction flag is the same as the flow from # 124 in FIG. If the previous direction flag is "0" (rear pin), the MF from the terminal (P01)
Set the signal to "Low" and extend the lens as shown in Table 6. If the previous direction flag is "1" (front pin), the terminal (P0
Set the MR signal from 0) to "Low" and move the lens in the retraction direction. In # 156, check the driving flag to see if the lens has been driven so far.
If it is driving (I will explain later, driving here means automatic focusing outside the near zone),
Loop to # 40 "CDINT" and enter the next focus detection. If the lens has been stopped so far, the driving is started in # 155, so the driving flag is set in # 157. # 1
In 58, check the fill light mode flag to see if it is fill light AF mode. If it is fill light AF mode, # 231 in Fig. 14
Branch to "L2 SAVE" from. If it is not the auxiliary light AF mode, check whether the lens is driven in the near zone by checking the near zone flag at # 159, and if it is in the near zone, proceed to "WSTOP" from # 160. 1 for # 160 and # 161
Only the end check is repeated at 00ms intervals, and the process does not return to the next focus detection loop. Then, it waits until the lens completely stops at the in-focus position, waits for the lens to stop, and then starts focus detection for in-focus confirmation. This is to interrupt the "INT3S" interrupt of # 252 in Fig. 16 while rotating the "WSTOP" loop to control the lens.

The reason why focus detection is not performed while driving the lens in this near zone is as follows. First, the lens drive in the near zone has acceleration rather than constant speed. That is, the lens has a positive acceleration at the start of driving the lens and has a negative acceleration before the lens stop position. When entering the near zone from high speed driving and switching to low speed, it has negative acceleration. Here, originally, the near zone count amount NZC is determined based on the count value from high speed until the motor (MO1) is de-energized until the lens movement stops, and the motor (MO1) is constant speed. It is not an area for movement. Here, the fact that the speed is not constant means that even if the sensor is integrated while the motor is being driven, it cannot be represented as the point at which the subject data was obtained at the intermediate position of the integration time. Therefore,
Even if the correction for the movement amount as described above is made, the correction is not accurate and has a calculation error of the lens driving pulse.
Therefore, it is desirable not to integrate the sensor when the lens is not moving at a constant speed. Therefore, in this embodiment, focus detection is not performed during acceleration or deceleration.

Next, when # 159 is judged to be outside the near zone, # 1
It branches to 62 and waits for 10ms here. Since the lens is accelerating from the stopped state, it waits for 100 ms until the speed becomes constant. Then, the end check is performed at # 163. The end check cycle may be too short or too long. If it is shorter than the pulse interval of the encoder according to the movement of the lens, it will be judged that it has stopped, and if it is too long, the durability of the drive system of the motor, gear, clutch, etc., and reversal drive at the end Since there are problems such as the responsiveness of, the interval is set to several tens to 200 ms. Next, in # 164, see the 1-cut shot flag and set 1
-Check if it is in cut shot mode,
In the 1-cut shot mode, the focus is not detected while driving the lens, so the # 160 “WST
Go to "OP", wait for the lens to stop, and after that stop focus detection for confirming focus. If it is not in 1-cut shot mode, loop to # 39 “CDINTA” in FIG. The above is the main routine of automatic focus adjustment.

Next, the branch routine and the subroutine from FIG. 13 will be described. First of all, "LOWCO
The “N” flow is a flow that branches from # 88 of the main routine of FIG. 11 when the result of the focus detection calculation is low contrast. First, in # 165, the terminal end is checked, and in # 166, the AF mode flag is checked to see whether or not the AF mode is set. If in AF mode, go to # 167 and set the low contrast flag last time, and at # 168, display LL and LR signals of the terminals (P32) and (P30) at the same time by repeating "Low" and "High" as low contrast display. LED (LEDL) (LEDR)
Blinks. Then it immediately loops to the next focus detection. If it is not the AF mode, the process proceeds from # 166 to # 169 to check the driving flag to check whether the motor is driving. If it is driving, there may be a case where low contrast scanning is in progress and a case where low contrast has been obtained during automatic focus adjustment. If the focus is being adjusted, the result of low contrast is ignored until the lens is stopped, as described above, so the process immediately proceeds to # 40 "CDINT" to start the next focus detection. # 170 during low contrast scan
If you come to # 171, get out of the low contrast state at # 171 and adjust the event counter value T3 at the end of calculation to the maximum count value 65,000 in order to correct the movement amount during renormalization integration when starting automatic focus adjustment. Set to. (Details will be described later) Similarly, motor drive event count value
EVTCNT, end detection count value MECNT also has maximum count value 6
Set it to 5,000. And it loops to "CDINT" of # 40.

If the contrast is low when the lens is stopped, proceed from # 169 to # 172. Then, if the scan prohibition flag indicating prohibition of the low contrast scan is set, the process proceeds to # 173. It should be noted that the fact that the scan prohibition flag fluctuates indicates that the low-contrast scan has already been completed once, or that there has been contrast.

Steps # 173 to # 175 and # 181 to # 183 are steps in which it is determined whether or not the auxiliary light AF mode is entered. The conditions for entering this auxiliary light AF mode are that it is first in AF mode, that the subject has low contrast, that the lens is stopped and that it is low light, and that the auxiliary light shown in FIG. It means that the electronic flash device with the lighting device is attached to the camera, the AFFL signal indicating that the auxiliary light can be emitted is coming, and the charging completion signal RDY is coming. Enter auxiliary light AF mode. First # 17
3 for low light flag, # 174 for fill light OK signal AFFL, # 17
When you see the charge completion signal RDY at 5, if all the conditions are "1", jump to "LLLED" from # 225 and enter auxiliary light AF mode. If this condition is not met, the low light state is checked based on the low light flag in # 176, and if it is low light, the maximum integration time of the sensor is doubled to 200 ms in # 177. AGC is 8 times with integration time of 100ms, low contrast,
This is because, in the case of low light, if the product time for one step is increased, it may become possible to detect the focus instead of the low contrast. However, since the error is generated when the focus is detected while driving the lens when the integration time is long, the maximum integration time is set to 200 ms mode only when the lens is stopped.

In # 178, the previous low contrast flag was set, in # 179, the LED (LEDL) (LEDR) indicating the low contrast state was blinking, and in # 180, the near zone flag and renormalization integral flag (renormalization integral F in Table 5-1). ), Clear the inversion flag, end flag, and end 2nd flag, and loop to "CDINT" of # 40.

If the low contrast scan is not prohibited in # 172, the flow branches to "SEARCH" from # 181. The flow from # 181 to # 195 is a flow for starting the low contrast scan. First, in steps # 181 to # 183, the conditions for entering the auxiliary light AF mode are determined in the same manner as the flow from # 173 to # 175. Then, if the conditions are met, it jumps from # 183 to #LLLED of # 225 and enters auxiliary light AF mode. If the AFFL signal is not "1" because it is a low light but the auxiliary light illuminator is not set, proceed from # 181 to # 182, # 184, where the maximum integration time of the sensor has already been reached. Check if it is in 200ms mode.

If it is not in the maximum 200ms mode, jump to "LL200" of # 230, set the 200ms mode flag and # 39.
Loop to "CDINTA". # 184 already up to 2
If it is low contrast even if it is in 00ms mode, or if it is low contrast in # 181 but not low light, proceed to # 185 and clear the 200ms mode flag.

This is because if the integration time is long during low-contrast scanning, the image of the subject tends to flow as described above, causing low contrast, and even if there is contrast, the integration time and focus detection If the maximum calculation time is reached, it is possible to have a lens with a large drive ratio, in which the lens has stopped, and when the focus is detected again, it has already gone too far beyond the in-focus range. For this reason, the 200ms mode flag is cleared and the maximum integration time is set to 100ms.

Next, in the flow from # 186 to # 190, the method of starting the scan of the lens at the time of low contrast scan is determined. When the subject is bright, the low contrast scan starts scanning from the direction determined by the focus detection calculation (# 188). Even if it is determined that the contrast is low and the defocus amount is not obtained, it may be obtained in the defocus direction, so scanning is performed according to the direction of the calculation result. If the area where the defocus amount is obtained during the low contrast scan comes, the automatic focus adjustment operation starts as described above. In the low contrast scan, if the lens is at one end, it is driven in reverse, and if it is at the opposite end, the scan ends. # 18 depending on whether the subject is dark or bright
6-Indicates whether the integration time exceeds 50 ms 1-cut shot
Checking using flags. For this, AGC data may be used, and the darkness may be 2 times or more, or 4 or 8 times or more. On the other hand, when it is dark, the process proceeds to # 187 to start the low contrast scan from the feeding direction. In this way, the final stop position at the end of the low-con scan ends with the lens retracted at the infinity end. This means that when the lens is capped, it will end in the retracted state, and the lens will be compact and convenient for storage in the camera case.

At this time, if the function of ending the lens by retracting the lens is emphasized instead of the purpose of searching for the contrast, the process may proceed to # 187 “LLIGHT2” without proceeding to # 187. That is, in # 189, a per-scan flag (F per scan) indicating that the low-conscan has hit the end once is set.
At 190, set MR signal to "Low" and start low contrast scan in the renormalization direction. When the lens hits the infinity end, # 189
In the "ROTEM" from # 199 in FIG. 14 determined by the per-scan flag, it is determined that the scan is completed, and the lens is stopped. Since "LLIGHT2" is included as a modification, # 189 and # 190 may be deleted.

In # 191, the low control flag is set to "1" last time, and in # 192, the scanning flag is set. In # 193, the maximum defocus amount FERM when the lens is stopped is set to 65,000. Similar to # 171 in # 194, maximum value of 6 for T3, EVTCNT, MECNT
Set 5,000. When driving the lens in # 195, the display is turned off. Then, while scanning, the process returns to the next focus detection loop # 40.

Next, the explanation will be given on the termination check subroutine "CKLOCK" in FIG. In # 196, it is checked whether the lens is being driven by looking at the driving flag, and if it is not driving, the end is not checked and the process returns. # While driving the lens
Proceed to 197 to check the end. The end check register MECNT set with the same value as the lens drive pulse count value DRCNT during driving is compared with the count value EVTCNT of the event counter set as the lens drive count value DRCNT. If the lens is moving, EVTCNT
The value of is decremented by 1 each time a pulse from the encoder (ENC) comes in, and is a value different from MECNT. If the lens does not move at the end, no pulse comes from the encoder (ENC), so EVTCN
The value of T does not change and remains the same as MECNT. therefore#
If MECNT = EVTCNT in 197, it is determined that the lens is stopped, and the process branches to # 199 in the termination processing flow “ROTEM”. If MECNT ≠ EVTCNT, it is determined that the lens is moving, and the process proceeds to # 198. # 198: EVTCNT instead of MECNT
The value of is reset and prepared for the next termination check.
Then return.

In the termination processing flow "ROTEM" from # 199, the subroutine is branched first, so the stack pointer of the microcomputer is reset. Disable interrupts other than INT1 and INT2 with # 200. Since it hits the end, the power is cut off to the motor (MO1) in # 201 and # 202, and the brake is applied. In # 203, the motor (MO1) is stopped, so the driving flag is cleared. If the previous direction flag is checked at # 204 and the previous direction flag is "0" (it is the rear pin and the lens is extended), # 205 means that it stopped at the closest end position, and the end position flag Set "1" to. If the previous direction flag was "1" (it was the front pin and the lens was retracted), the end position flag is cleared in the sense that it stopped at the infinity end position at # 206. In # 207, it is checked whether or not the end is hit during the low contrast scan, and if it is in scanning, the process proceeds to # 208, and the end flag that the lens is stopped at the end is set. In # 209,
Furthermore, based on the fill light mode flag, it is checked whether or not it is in fill light AF mode.If it is in fill light AF mode, if it hits the end, even if it is focus detection by the first flash, the next Instead of looping to the focus detection of, the LED blinks and the focus detection is given up. The auxiliary light AF mode will be described in detail in the "LLLED" flow from # 225. If it is not in the auxiliary light AF mode with # 209, the next focus detection loop "CD
Go to INTA ”.

In # 207, if the lens is at the end during the low contrast scan, proceed to # 210 to check if it has hit the end during scanning, that is, whether it is going or returning, and If there is, it is necessary to reverse the scanning direction and move it, so proceed to # 217. # 217, this time
Since it has reached the end, the per-scan flag is set. Next, in # 218, the previous direction flag (indicating the lens driving direction) is checked, and in # 219 and # 221, the directions are reset in the opposite directions. Then, in # 220 and # 222, the lens drive signal MR or MF is set to "Low" according to the next moving direction. At this time, of course, the brake signal MB is set to "High". With this, the inversion drive is started. # 2
23, FERM, T3, EVTC
Reset NT and MECNT to the maximum value of 65,000 respectively. In step # 224, the driving flag is set to "1" and the process goes to the next focus detection loop "CDINTA".

On the other hand, if it has already hit the end and it was the second end, proceed from # 210 to # 211. This time, the lens does not move because the low contrast scan is completed. # 211 clears the per-scan flag that hits the end of the scan, # 212 clears the in-scanning flag, # 2
In the case of 13, the scan prohibit flag is set because once scanning is done, the rest is not done. In # 214, I did a low contrast scan, but I could not find the contrast,
Since the focus could not be detected, the LED blinks. In # 215, it is checked whether or not the auxiliary light AF mode is in effect. If it is in the auxiliary light AF mode, the process goes to # 216, waits for an interrupt without going to the next focus detection, and ends as it is. If it is not the fill light AF mode, focus detection is repeated at the end position after scanning is completed.
Return to TA. The above is the end detection routine.

Next, the auxiliary light AF mode routine will be described. Auxiliary light AF
The mode is entered from the "LOWCON" routine in Figure 13. If the above conditions are met, the process proceeds from # 175 or # 183 to "LLLED" in # 225, and the auxiliary light AF mode flow is entered. In # 225 of FIG. 14, first, an auxiliary light AF mode flag indicating the auxiliary light AF mode is set. In # 226, set the signal from the terminal (P13) to the terminal (ST4) to "High". The flash circuit (FLS) causes the auxiliary light LED (48) to start emitting light in response to this signal. In # 227, the LL and LR signals are set to “Lo” to notify the outside that the auxiliary light AF mode has been entered.
w "and turn on the LEDs (LEDL) (LEDR) on both sides. The lighting time is up to 45 until the next focus detection calculation ends.
It is standard to turn on for 0 ms. This is the total time when the # 229 waits for 200 ms, the calculation time for focus detection, and the maximum integration time is 200 ms. To do. That is, this is also because the display is turned off while the lens is being driven. This display is only once when the auxiliary light AF mode is entered. On the other hand, the auxiliary light LED (48) emits light twice.
The auxiliary light AF mode sequence starts with the auxiliary light LED (4
8) emits light once and the CCD image sensor (F
Preliminary lighting for LM). This is to improve the responsiveness of the CCD image sensor (FLM). And
CC under auxiliary light illumination in mode with maximum integration time of 20 ms
Integrate D. Then, the focus detection calculation is performed based on this data, and the lens is driven. During this time, focus detection is not performed. And after stopping the lens, the second LED for auxiliary light (48)
After a maximum of 450 ms as in the first time, if the focus detection result is not within the focus zone, the lens is driven again to perform focus adjustment. This is the basic movement.

Here, it is necessary to distinguish whether the LED (48) for auxiliary light emits light for the first time or the second time. In order to distinguish this, an auxiliary light 1st flag (auxiliary light 1stF in Table 5-2) is provided. If "0" is entered in this flag, it indicates that the first light emission has occurred, and if "1" indicates that the second light emission has occurred. #
In 228, "0" is put in this flag. In # 229, wait 200 ms as the preliminary illumination time of the sensor, and set in 230 the mode in which the maximum integration time of the sensor is 200 ms. Auxiliary light A
In F mode, the integration time is usually 200ms. Then, it loops to "CDINTA" as in normal AF mode.

The flow proceeds from # 39 in FIG.
Turn off the auxiliary light at # 69 in the figure. In the same way, focus detection is performed
At # 87 in the figure, the flow branches to the auxiliary light AF mode flow “LSAVE” in # 238 in FIG. This is the flow starting from # 238.

First, it is determined whether or not the focus detection in the auxiliary light AF mode is the first time, and if it is the first time, the process proceeds to # 239. Here, it is checked whether or not the focus detection calculation result is low contrast, and if it is low contrast, the process proceeds to # 233, and the second auxiliary light emission starts. I don't give up immediately because I got low contrast with one auxiliary light emission, so I try again. For subjects near the low contrast limit, the first auxiliary light emission gives the CCD sensor the effect of preliminary light emission, increasing the sensitivity,
This is because the AF operation may be possible during the second flash. If # 239 is not low contrast, then # 9 in Figure 11
Go to “NLOC1” in 1 and enter the flow for focus adjustment drive. In this case, driving is started at # 155 through # 91 to # 102 in FIG. 11 and then through # 141 in FIG.
From the auxiliary light AF mode "L2SAVE"(# in Fig. 14)
231).

In # 231 of FIG. 14, it is checked whether or not the emission of the auxiliary light is the first time based on the auxiliary light 1st flag, and if it is the first time, the process proceeds to # 232. Here, the lens is driven by the count amount of the focus detection calculation result, and after the movement of the lens is stopped, the process proceeds to the second auxiliary light emission flow # 233. In # 233, see the fill light OK signal AFFL, and if it is “1” (OK), #
At 234, the second auxiliary light emission signal is output (that is, the signal at the terminal (ST4) is set to "High"). If the AFFL signal is "0", the auxiliary light illuminator has been turned off, so the second light emission is not performed. In this embodiment, the auxiliary light AF mode is not released in this case, but it may be released.

# 235 sets the auxiliary light 1st flag, and the second auxiliary light
Show that it is in AF mode. And like the first time, wait 200ms at # 229, go through # 230, and go to # 39 “C
Go to "Dinta". In the case of the auxiliary light AF mode in the second auxiliary light AF mode, the same flow is followed, through # 39 in FIG. 9 to # 44 and # 68 in FIG. 10, and in # 87 in FIG. To branch to “LSAVE” in # 238 of FIG. This time is the second auxiliary light AF mode, so proceed to # 240.

Check whether it was low contrast in # 240, and if it is low contrast, proceed to # 211 and again,
Without stopping the lens, keep the LEDs on both sides (L
EDL) (LEDR) blinks and waits for an interrupt.

If not low contrast, # 240 to # 91 in Fig. 11
Proceed to and enter the lens drive flow. And in Figure 12 #
Branch to "L2SAVE" in the auxiliary light AF mode flow until 158. In # 231, it is the second auxiliary light AF mode, so # 2
Proceed to 36 and wait for the lens to stop like the first time. If it is not in the auxiliary light AF mode, focus detection for focus confirmation is then performed, but since the emission of auxiliary light is limited to two times, focus detection for confirmation is not performed. (In this embodiment, since the light is emitted up to twice, the following processing is performed without confirmation. However, the number of times of light emission is not limited, and light may be emitted until the focus is confirmed. This process checks the focus detection calculation value FERM when the lens is stopped. That is, if the defocus amount at the start of the second lens drive is less than 1 mm, it is determined that the lens can be brought into the focus zone without sufficiently confirming the focus, considering the focus detection performance. In Step # 117 of Fig. 11, the flow for focusing is proceeded to "INFZ" to display the focus. If the FERM is 1 mm or more, the result of focus detection for the first time and the result for the second time are significantly different, and it is assumed that reliable focus detection could not be performed, so proceed to # 211 and leave the lens at the current position. LEDs on both sides (LED
L) (LEDR) blinks. The above is the auxiliary light AF mode routine. Limiting the emission of the auxiliary light LED (48) to two times is that power consumption and usage problems occur when the number of times of light emission is large, and focus detection error and backlash error occur when it is once. Therefore, 2 times are appropriate. If the second focus detection is not possible, the lens is not retracted. If you open the switch (S1) once and then close it again and try the auxiliary light AF mode again, This is because it is determined that there is a high possibility that the subject will start in the vicinity of the focus of the subject, and the possibility of bringing the lens in the focus zone will increase.

Next, the event counter interrupt flow "INT3
Let's start the explanation about "S". This is an interrupt pin (INT
3) The lens drive control is performed using the pulse signal PS from the encoder (ENC) of the lens drive motor (MO1) that enters. The drive count value EVTCNT of the lens up to the in-focus position was obtained by focus detection calculation. The interrupt signal to INT3 constantly monitors the lens drive amount, and controls the lens moving speed and stop position. First, the drive count value EVTCNT is set in the event counter when the lens is driven. Then, the energization of the lens driving motor (MO1) is started. Then, the lens starts to move, a pulse is output from the encoder (ENC) and INT3 is interrupted. And the flow of "INT3S" of # 252 starts.

First, the count value EVTCNT of the event counter is decremented by "1" because the "1" pulse signal comes at # 252. Then, in # 253, it is checked whether or not this count value EVTCNT has counted the specified amount (that is, "0"). If EVTCNT becomes "0", it means that the lens has come to the in-focus position and the process proceeds to # 259. , Stop the drive of the motor (MO1).

If the count value EVTCNT of the event counter is not "0", proceed to # 254 to check whether the lens is in the near zone based on the near zone flag. If the near zone flag is not "1", proceed to # 255,
I will check to see if I entered the near zone with this pulse. If the count value EVTCNT of the event counter is smaller than the count value NZC of the near zone counter at # 255, it means that the player has entered the near zone this time, and the process proceeds to # 256. If it is outside the near zone, it returns from the interrupt flow of "INT3S" to the main flow. On the other hand, in # 256, the near zone flag is set for the first time this time, so the near zone flag is set, and in # 257, the MC signal from the terminal (P03) is set to “Low”, and the drive of the motor (MO1) is switched to low speed. . Then, in # 258, the stack pointer of the interrupt flow is reset, and the process proceeds to "WSTOP" in # 160 in Fig. 12 to wait for the lens to stop while checking the end.

In other words, while looping through this "WSTOP" flow, "INT
3S ”interrupt enters, the flow from # 252 to # 254, # 258 is repeated, and when the count value EVTCNT becomes“ 0 ”,
Exit this loop and proceed to # 259. If you are in the near zone, the process proceeds to # 160 “WSTOP” and does not return to the main flow because, as mentioned above, focus detection is not performed when the lens is not moving at a constant speed. Since the lens decelerates, it is not a constant speed, so if it enters this area, focus detection is not performed while moving the lens.

Next, when the lens has moved by the drive pulse count value EVTCNT, the count value EVT is checked by checking in # 253.
Since CNT becomes “0”, proceed to # 259. Here, the lens drive motor (MO1) is de-energized, the brake is applied at # 260, the driving flag is cleared at # 261, the event counter interrupt is disabled at # 262, and the process goes to # 263. move on. Here, it is checked whether or not the auxiliary light AF mode is in progress, and if it is in the auxiliary light AF mode, the process returns from this event counter interrupt. This return destination is # 232 in FIG. 14 as described in the flow of auxiliary light AF mode.
To # 236. If it is not in the fill light AF mode in # 263, the stack pointer is reset in # 264 and the process proceeds to # 265.

The flow from here is to determine whether or not to go to the focus detection for confirming whether the stop position of the lens is within the focusing zone after the focus adjustment driving. First,
Check the DR signal sent from the control microcomputer (MC2) to see if it is single shooting mode or continuous shooting mode. If the DR signal is "0", that is, the single shooting mode, # 267
s Wait, the lens will come to a complete stop from low speed, then enter the next focus detection loop. Then, if it is confirmed by the next focus detection that it is within the focusing zone, that is, if it is checked in step # 116 of the main flow of FIG. do. If the position where the lens stops is not within the focusing zone,
The routine for driving the lens is entered again from # 120 in FIG. 11, and the same operation is repeated. This is the flow when confirming the focus. Next, in the continuous shooting mode, since the DR signal is "1", the process proceeds from # 265 to # 266 in FIG. Here, when the lens is stopped (when the driving flag is "0"), the defocus amount (FE
Check RM). If this value is 500 μm or more, proceed to # 267. That is, in the continuous shooting mode, if the defocus amount before driving the lens is 500 μm or more, the focus is confirmed. # 266, FERM is 500μm
If less, go to # 268 and check if the reversal flag is on.If the reversal flag is on, it means that the backlash has been corrected. Go towards. If the reversal flag is not set at # 268, the flow goes to the focus display flow of "INFZ" at # 117. This is a method for increasing the lens drive speed to improve the followability to a moving subject in the continuous shooting mode. When automatic focus adjustment is performed from a position within 500 μm without correcting backlash. The system has a good linearity and goes to the in-focus display directly without performing focus detection for in-focus confirmation with the belief that the system is surely within the in-focus zone. In other cases, go to the focus confirmation and improve the focus accuracy. However, if the focus detection capability is further improved and there is almost no drive system error, the focus confirmation may not be necessary here. The above is the sequence of automatic focus adjustment.

Finally, the flow from # 40 to # 53 in FIG. 9 will be described. This is a flow related to so-called "renormalization integration", and the details of this are described in Japanese Patent Application No. 60-7179 by the present applicant, and are not the object of the present application, so that they are omitted here.
This "renormalization integration" starts from # 66 in FIG.

When it is determined that the lens is being driven by checking the driving flag in # 65, it may or may not be in the “convolution integration” state, but the next integration is started in # 66, and the convolution integration flag ( The renormalization integral F) in Table 5-1 is established. The top of the focus detection loop when "convolution integration" is required is "CDINT" of # 40 in FIG.

Now consider the case where the subject is dark. The integration mode is set in # 40 so that the integration end signal NB4 can be detected. Then, in # 42, it is checked whether or not the renormalization integration flag is set. If not, the renormalization integration mode is not set, so the flow proceeds to # 44. If the renormalization integration flag is set, the process proceeds to step # 43, where the integration end signal NB4 is checked to see if the integration has already been completed. If the integration has not ended, the process proceeds to # 49 “TINTC”, that is, the flow from “TINTC” is the renormalization state, and “CDINTS” from # 44 is for non-renormalization. 10th
In # 49 of the figure, the 1-cut shot flag is set to "1". # 50 in
The AFE signal is set to "Low", and as described above, T1 'is corrected in preparation for movement correction in # 51. Set the maximum remaining integration time of 40 ms in # 53 and proceed to # 55. The following is the flow of the main routine. The "convolution integration" has the effect of shortening the focus detection time in this way. AF over
This concludes the explanation of the flow of the microcomputer (MC1).

FIG. 19 is a modification of # 403 to # 407 and # 119 of the first embodiment described above. In the method of # 403 to # 407, in the case of the auxiliary light mode in the continuous AF mode, focusing is achieved. After that, the auxiliary light is emitted repeatedly. When the subject is not moving, it means that the subject is still in focus, so that the same step 403 is entered, the step 403 is entered again, and the auxiliary light is emitted again.

Such operation may be troublesome.

The embodiment shown in FIG. 19 is an improvement of the above points.
Subsequent to the processing of 9, it is determined whether or not the auxiliary light mode is the auxiliary light mode by the auxiliary light mode flag MF in # 410.
The interrupt is waited at # 414, and the charge integration in the CCD image sensor is not performed. By this operation, even in the continuous AF mode, the operation is the same as in the one-shot shooting only in the auxiliary light mode. If it is not the auxiliary light mode, proceed to # 411, judge whether the continuous AF mode is the one-shot AF mode, and if it is the continuous AF mode, if it is the "CDINT" one-shot AF mode of # 39, proceed to # 412. Then, the same operations as # 405 and # 406 of the first embodiment are performed.

FIG. 20 is a flowchart showing the second embodiment, which is a portion corresponding to steps # 238 to # 240 of the first embodiment.

In the first embodiment, if the auxiliary light mode is entered, for example, even if it is determined that the subject has low contrast, the auxiliary light is emitted only twice. In the second embodiment, in consideration of the intention of the continuous AF mode, when the subject has a low contrast, the auxiliary light emission is continued until the contrast is obtained. In this case, the lens is not scanned and the lens is stopped, and only the focus detection operation is performed during this period.

In FIG. 20, in # 238, it is determined whether or not the auxiliary light is the first emission, and if it is the first emission, the process proceeds to # 239, in which it is determined whether or not the subject has a low contrast. . If the subject is low contrast, proceed to # 233 in both continuous AF mode and one-shot AF mode.
The auxiliary light is emitted. If the subject has contrast #
Go to 91 and perform AF operation. Then, when the auxiliary light is emitted for the second time, the process proceeds from # 238 to # 240. In # 240, it is determined whether or not the subject has low contrast, and in # 91, the AF operation is performed. If the subject has a low contrast, it is determined at # 415 whether the continuous AF mode is the one-shot AF mode. Then, in the continuous AF mode, the process proceeds to step # 233, and the auxiliary light is continuously emitted. At this time, the lens is stopped. If the subject has low contrast in the third light emission, the flow returns to # 415, and # 2
Go to 33 and cycle.

On the other hand, in the one-shot AF mode, the auxiliary light emission is 2
It ends with the number of times and goes to # 59, "CDINTA", and repeats focus detection only.

EFFECTS OF THE INVENTION According to the present invention, when the second operation mode (auxiliary light emission mode) for operating the focus detection means in a state in which the auxiliary light illumination means is operated is set, the focus state of the photographing lens is changed. When it is determined that the detection is impossible, thereafter, the focus detection means is set to the first operation mode in which the focus detection means is operated while the auxiliary light illumination means is not operated, and the focus detection means is operated. Since the focus detecting means is controlled so as to repeat, the focus state is detected immediately when the focus state can be detected by pointing the camera in a bright direction. Therefore, it is possible to quickly respond to changes in the situation of the subject, and since the auxiliary light is not emitted when the detection of the focus state is repeated, power consumption is low and deterioration of the light source of the auxiliary light can be prevented. There are advantages.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an entire camera system of an embodiment of the present invention, FIG. 2 is a block diagram showing its electric circuit, FIG. 3 is a circuit diagram showing a flash circuit of its electronic flash device, and FIG.
5 and 5 are flowcharts showing the operation of the control microcomputer, FIG. 6 is a block diagram showing the interface circuit, and FIGS. 7 to 16 are flowcharts showing the operation of the AF microcomputer. FIG. 17 (A). (B) is a time chart showing interrupt signals, FIG. 18 is a schematic diagram for explaining the focus detection principle of the embodiment of the present invention, and FIGS. 19 and 20.
The figure is a flow chart showing another embodiment of the present invention. (LZ); Photographic lens (FLM); Charge accumulation type image sensor (113); AF controller (MC1); AF microcomputer 48; Auxiliary light source.

Claims (1)

[Claims] 1. A light for a subject which has passed through a photographing lens is received,
A light receiving unit that outputs a subject image signal, a focus detecting unit that detects the focus state of the photographing lens based on the subject image signal output from the light receiving unit, and a subject for detecting the focus state by the focus detecting unit. An auxiliary light illuminating means for illuminating the object, a determining means for determining whether or not the focus state can be detected based on the subject image signal output from the light receiving means, and the auxiliary light illuminating means without operating the auxiliary light illuminating means. Mode setting means for selectively setting a first operation mode for operating the focus detecting means and a second operation mode for operating the auxiliary light illuminating means and operating the focus detecting means in a state where the subject is illuminated. And when the mode setting means sets the first operation mode, the determination means determines that the focus state cannot be detected. At this time, when the second operation mode is set by the switching means for controlling the mode setting means so as to switch to and set the second operation mode, the determination means makes the above-mentioned When it is determined that the focus state cannot be detected, the mode setting means is controlled so as to fix and set the first operation mode thereafter, and the focus detection means repeats the operation. A focus detection device comprising: a control unit that controls the focus detection unit.