JPH0810295B2 - Auto focus camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an automatic focusing system, and more specifically, to detecting a defocus direction and a defocus amount of an imaging position of a subject with respect to a planned focus position, and detecting the defocus amount. The present invention relates to an automatic focusing system that drives a taking lens to a predetermined focus position based on the result.

[Prior Art] Conventionally, an automatic focusing camera in which a shift amount detecting operation is started by lightly pressing the release button halfway and the photographing lens is driven to an in-focus position according to the output result is disclosed in JP-A-56-1024. Various publications have been provided, including the gazette.
This type of automatic focusing camera is easy to operate because the automatic focusing operation is started only when the photographer points the camera at the subject to be photographed and intentionally presses the release button halfway. This has the advantage that the automatic focusing operation is rarely performed on the intended subject.

Most of these auto-focusing cameras with interchangeable lenses use a storage photoelectric conversion element such as a line image sensor using a CCD as a defocus direction or defocus amount detection device. This storage-type photoelectric conversion element can detect the defocus amount by the light from the subject to be focused that has passed through the lens, and thus can be said to be an element suitable for equipping an automatic focusing device.

However, such a storage-type photoelectric conversion element has a narrow dynamic range with respect to the amount of light and cannot be used as it is under all the brightness conditions that can be photographed. Therefore, the storage time must be adjusted according to the brightness of the subject. . Therefore, the accumulation time is long for a low-luminance subject, and the defocus amount detection takes time accordingly. Therefore, in the conventional auto focus adjustment type where the automatic focus adjustment operation is started for the first time by half-pressing the release button, when the subject has low brightness, from the half press of the release button to the actual lens adjusting operation. There will be a time lag of several hundred ms. This time lag is very long and frustrating for the photographer.

On the other hand, in the automatic focusing camera, a photograph in focus cannot be obtained unless the subject to be focused is placed in the distance measuring frame at the center of the finder and then the release button is pressed halfway. Therefore, since the photographer carefully performs this operation, there is a time lag (time lag) from the time when the desired subject is placed in the focus detection frame until the release button is half-pressed. . This time lag is larger than expected and is sufficiently longer than the time required to detect the defocus amount even for a subject having a relatively low brightness. Therefore, if the defocus amount detection operation can be repeated until the release button is half-pressed, it is possible to eliminate the time lag from the half-pressing of the release button to the actual lens adjusting operation.

Therefore, the applicant of the present application has previously disclosed in Japanese Patent Application No. Sho 62-042074 that automatic focusing is performed for a low-brightness subject so that a lens adjusting operation is started without a time lag in response to a half-press operation of a release button. I suggested a camera.

[Problems to be Solved by the Invention] Even in the camera proposed above, the automatic focus adjusting operation of the lens driving means starts after the release button is half-pressed, so that the conventional camera without the automatic focus adjusting mechanism is used. Compared with, the lens driving period of tens to hundreds of msec,
It still remains as a release time lag.

Therefore, an object of the present invention is to reconsider the time when the lens driving means starts the automatic focus adjustment operation when the release button is half-depressed, and when the photographer looks into the viewfinder, the release time lag is reduced. It is to provide an autofocus camera that minimizes.

Another object of the present invention is to minimize the release time lag by starting the time when the defocus direction and the defocus amount of the imaging position with respect to the planned focus position are started when the photographer holds the camera. To provide an autofocus camera.

[Means and Actions for Solving Problems] A first automatic focusing camera according to the present invention provides a driving unit that electrically drives a focusing lens and a defocus amount with respect to a planned focal position of an imaging position of a subject. Focus detecting means for detecting, a human body detecting means for detecting that the photographer is looking into the eyepiece of the camera body and outputting a human body detecting signal, and responding to the human body detecting signal, and by the focus detecting means Drive control means for controlling the drive means based on the detected defocus amount.

A first automatic focus adjustment camera according to the present invention includes a drive unit that electrically drives a focus adjustment lens, a focus detection unit that detects a defocus amount of an imaging position of a subject with respect to a planned focus position, and a grip portion of a camera body. And a holding detection means that outputs a holding signal when the photographer holds the grip portion, and outputs a human body detection signal by detecting that the photographer is looking into the eyepiece of the camera body. When the holding signal is output from the human body detection means and the holding detection means, and the human body detection signal is output from the human body detection means, based on the defocus amount detected by the focus detection means, And drive control means for controlling the drive means.

In addition, the second automatic focus adjustment camera according to the present invention includes a human body detection unit that outputs a human body detection signal by detecting that the photographer is looking into the eyepiece of the camera body, and outputs the human body detection signal. Control means for repeating the operation of detecting the defocus amount with respect to the planned focus position of the imaging position of the subject and the operation of driving the taking lens based on the defocus amount, while the subject has low brightness. , The projection means for projecting the auxiliary light to the subject in synchronization with the operation of detecting the defocus amount, and the projection of the auxiliary light are prohibited until the release button of the camera is operated. After the button is operated, a projection control means for permitting the projection of the auxiliary light is provided.

Furthermore, the third automatic focusing camera according to the present invention is
A human body detection unit that detects that the photographer is looking into the eyepiece of the camera body and outputs a human body detection signal, and a defocus amount detection unit that detects the defocus amount of the imaging position of the subject with respect to the planned focus position. A driving means for driving the photographing lens based on the defocus amount detected by the defocus amount detecting means, and the defocus detecting means and the driving means while the human body detection signal is being output. Control means for repeatedly operating,
Operation detecting means for detecting whether or not the release button of the camera is operated by the photographer, and detection of a new defocus amount and driving of the taking lens after the operation of the release button is detected by the operation detecting means. And a prohibition means for prohibiting.

[Example] Before describing a specific example of the present invention, a schematic configuration of the example will be described with reference to FIG. The first schematic configuration is, as shown in FIG. 1A, a photoelectric conversion element 2 that photoelectrically converts subject light that has passed through the taking lens 1, and detects this when the photographer holds the camera. Holding detection means 3; focus detection means 4 for detecting the defocus direction or the defocus amount of the imaging position with respect to the planned focus position based on the output of the photoelectric conversion element 2 according to the output of the holding detection means 3; Drive control means 7 for driving and controlling the drive means 6 of the photographing lens 1 based on the output of the focus detection means 4 according to the output of the control operation start means 5, and the photographer holds the camera. The focus detection operation is started when this is done.

The second schematic configuration is based on a photoelectric conversion element 2 that photoelectrically converts subject light that has passed through the taking lens 1 and an output of the photoelectric conversion element 2, as shown in FIG. 1 (B). Focus detection means 4 for detecting the defocus direction or the defocus amount with respect to the planned focus position of the image formation position.
A human body detecting means 8 which detects an operation of a photographer looking into the eyepiece and generates an output; and, in response to the output of the human body detecting means 8, the photographing lens 1 of the photographing lens 1 based on the output of the focus detecting means 4. Drive control means 7 for controlling the drive of the drive means 6, and the focusing operation is started when the photographer looks into the eyepiece.

Next, an embodiment of the present invention will be described with reference to the drawings starting from FIG.

FIG. 2 is a block diagram of the whole electric circuit mainly viewed from the power supply of the camera system to which the present invention is applied. The voltage V _CC of the power battery 11 is set when the power switch 12 is closed.
The voltage is boosted by the DC / DC converter 13, and the voltage between the lines l ₀ and l ₁ is made a constant voltage V _DD . MAIN between lines l ₀ and l ₁
The CPU 14, the bipolar II circuit 15, the bipolar I circuit 16, the lens data circuit 17, and the human body detection circuit 18 are connected,
The power supply control of the bipolar II circuit 15 is performed by a signal from the power control circuit of the MAIN CPU 14, and the power supply control of the bipolar I circuit 16 to the lens data circuit 17 is performed by a power control signal from the bipolar II circuit 15.

The auto-focus circuit, consisting of the CCD line sensor 20, interface IC21 and AFCPU22, is a power control transistor
It is connected between the lines l ₀ and l ₁ via 23, and the power supply control for this autofocus circuit section is performed by the MAINCPU 14
The on / off control of the transistor 23 is performed by a signal from the auto-focus power control circuit. The AF CPU 22 is a central processing unit for performing an algorithm calculation for auto focus, and is connected to an auto focus (AF) display circuit 24 for displaying in-focus and out-of-focus. The MAINCPU 14 is a central processing unit for controlling the sequence of the whole camera such as film winding, rewinding, and exposure sequence, and is connected to a display circuit 25 for performing display other than the above-mentioned in-focus display. Bipolar II
The circuit 15 includes various drivers necessary for the camera sequence, such as a motor control for winding and rewinding, a lens drive and a shutter control, and is connected to a motor drive circuit 26 and an auto-focus (AF) auxiliary light circuit 27. ing. The bipolar I circuit 16 is a circuit mainly for controlling photometry and has a photometric element 28. The lens data circuit 17 is a circuit that stores unique lens data, which differs for each interchangeable lens, and is necessary at the time of autofocusing, photometry, and other camera control. Among the lens data contained in the lens data circuit 17, data necessary for autofocus include lens magnification coefficient (zoom coefficient), macro identification signal, insulation distance coefficient a, b, autofocus accuracy threshold ETh, The lens rotation direction, open F value, and the like.

The bipolar II circuit 15 monitors the state of the power supply voltage V _DD , and when the power supply voltage drops below the specified voltage, MAIN
A system reset signal is sent to the CPU 14 so as to cut off the power supply to the bipolar II circuit 15 to the lens data circuit 17 and the power supply to the auto focus circuit section including the CCD line sensor 20, the interface IC 21 and the AFCPU 22. The power supply to the MAINCPU 14 is performed even at a specified voltage or less.

The human body detection circuit 18 forms a human body detection signal in response to a command from the MAIN CPU 14, and informs the MAIN CPU 14 of the result that the human body has been detected.

FIG. 3 is a schematic block diagram of an autofocus circuit section of the electric circuit shown in FIG. Data is exchanged between the AFCPU 22 and the MAIN CPU 14, which are the central processing units for autofocus, via a serial communication line. The communication direction is controlled by the serial control line. The contents of this communication are lens data unique to the interchangeable lens. Further, each information of each mode (autofocus / single mode or other modes) of the camera is decoded from the MAINCPU 14 to the AFCPU 22 through the mode line. To the MAIN CPU 14, signals of grip switches to be described later and other operation mode switches, for example, signals of various switches necessary for operating the camera such as a display start switch, an ISO setting switch, a self switch, and a mode selection switch are input.

Also, 1s that occurs in response to the half-press operation of the release button
The t.Rel (first release) signal is input to the MAINCPU 14 and further transmitted to the AFCPU 22 through this MAINCPU 14. 2nd generated by pushing the release button further.
The Rel (second release) signal serves as a trigger signal for starting the exposure sequence and is input to the MAIN CPU 14.

The human body detection circuit 18 generates a human body detection signal in response to the motion of the photographer looking into the viewfinder, and outputs the same signal to the MAINCPU1.
Send to 4.

Furthermore, the AFENA (auto focus enable) signal from the MAINCPU14 to the AFCPU22 is output in response to the human body detection circuit 18, and is a signal for controlling the start and stop of lens drive.
The EOFAF (End of Auto Focus) signal is a signal that is issued at the end of the auto focus operation and permits the transition to the exposure sequence.

The bipolar II circuit 15 also decodes the AF motor control line signal from the AF CPU 22 and drives the motor drive circuit 26. When the lens drive motor 31 is rotated by the output of the motor drive circuit 26, the slits 32 provided at equal intervals in the rotating member of the lens barrel rotate, and
The photointerrupter 33 in which the light emitting unit 33a and the light receiving unit 33b are arranged to face each other across the passage of 32 counts the slit 32. That is, the slit 32 and the photo interrupter 33 constitute an address generating unit 34, and an address signal (count signal of the slit 32) generated from the address generating unit 34.
Is waveform-shaped and taken into the AFCPU22.

The sub lamp (hereinafter abbreviated as S lamp) signal sent from the AFCPU 22 to the bipolar II circuit 15 is an AF auxiliary light circuit 27.
The S lamp 27a is turned on when the subject is in low light (low brightness).

The AF display circuit 24 connected to the AF CPU 22 has a focus OK display LED (light emitting diode) 24a that lights up when focusing, and an unfocusable display LED 24b that lights up when focusing is impossible. A clock oscillator 35 and a reset capacitor 36 are connected to the AFCPU 22.

The AF CPU 22 and the interface IC 21 exchange data via a bus line, and the transmission direction is controlled by a bus line control signal. And AFCP
A sensor switching signal and a system clock signal are sent from the U22 to the interface IC21. And
For example, the interface IC 21 sends a CCD drive clock signal and a CCD control signal to the CCD line sensor 20, reads out the CCD output from the CCD line sensor 20, converts the read analog output of the CCD output into digital by the interface IC 21, and sends it to the AF CPU 22. send.

FIG. 4 is a block diagram of the human body detection circuit 18 in the schematic block diagram of the autofocus circuit section shown in FIG. In FIG. 4, the human body detection circuit 18 has a first human body detection unit 41 using an infrared photoreflector and a second human body detection unit 42 using a pyroelectric infrared sensor. The output of the unit is input to the human body discrimination unit 55 to obtain a human body detection signal.

The first human body detection unit 41 is composed of an infrared light projecting system and an infrared light receiving system. The infrared light projecting system drives the infrared light emitting diode 47 by the output of the infrared LED drive unit 43, and is arranged in front of the infrared light emitting diode 47 to collect the projected light beam. Infrared light is projected through. At this time, the infrared LED drive unit 43 uses the modulation unit 4 to avoid the influence of sunlight.
It is modulated by 4. The infrared light projected from the infrared projection system is reflected by the human body 40 and enters the infrared reception system. The infrared reflected light is received by the photodiode 48 and photoelectrically converted through the light receiving optical system 50 including the diaphragm mechanism provided for the purpose of removing the disturbance nozzle as much as possible.
The waveform amplification and shaping section 45 performs amplification and shaping, and the detection section 46 outputs only the signal component in synchronization with the modulation signal from the modulation section 44. As described above, when the photographer looks into the finder, the first human body detection unit 41 configured by using the infrared photoreflector supplies the human body discrimination signal A to the human body discrimination unit 55 in response to the operation. .

The second human body detecting section 42 is composed of a pyroelectric infrared sensor (hereinafter abbreviated as pyroelectric detecting element) which is a type of light receiving element, and a chopper amplifying / detecting section thereof.

First, infrared rays emitted from the human body 40 approaching the camera are incident on the surface of the pyroelectric detection element 54 through a window material described later. A heat absorption film (not shown) is provided on the surface of the element, and the incident infrared rays are absorbed and converted into heat. This heat changes the element temperature, and an electric charge is instantaneously generated based on the pyroelectric effect. By the way, since the element 54 has a capacitive high impedance, it is not possible to directly take out electric charges as it is. Therefore, impedance conversion is performed by the source follower circuit using the FET 53. Therefore, the voltage output is taken out from the source terminal of FET53,
It is applied to the detection unit 52 via the waveform amplification unit 51 described later,
A human body discrimination signal B is formed and input to the human body discrimination unit 55.

In general, a silicon pyroelectric detection element has a flat sensitivity characteristic in a wavelength range of 0.2 to 20 μm, and therefore an optical filter (window material) is attached and used for human body detection.
Polyethylene, silicone, long-pass silicone, etc. are used as this window material, but it is used for human detection.
A μm long pass filter is suitable. Normally, the energy emitted from the human body has its peak at 9 to 10 μm, so that E001SX and E002SX4 manufactured by Murata Manufacturing Co., Ltd. are suitable.

By the way, since the pyroelectric infrared sensor is a "differential type" that outputs only when there is a difference in incident energy, it cannot be detected in a steady state where the photographer looks through the finder all the time. Therefore, it is necessary to configure a chopper of about 1HZ, and the waveform amplification section 51 also has this function.

The human body discrimination unit 55 uses the MAINCPU 14 to detect the first human body detection unit 4
AN for specifying whether the output of 1 and the output of the second human body detection unit 42 are determined by AND and OR is determined
D / OR select signal is input. This is selected by the photographer according to the mode of use of the camera, for example, the use of a self-timer, and is normally configured by taking an AND. The human body detection signal output from the human body discrimination unit 55 is MAIN
It is supplied to the CPU 14.

5A and 5B show an example in which the first human body detection unit 41 and the second human body detection unit 42 are arranged in the camera.
The first human body detection unit 41 is provided in the vicinity of the finder window 39, and the second human body detection unit 42 is provided in a substantially central portion of the back cover 38 of the camera 37.

Normally, the photographer looks through the finder window 39 of the camera as shown in FIG. 5 (A), and the action of looking through this finder is detected by the first human body detecting section 41. If the photographer wears glasses, the first human body detection unit 41 alone may not perform a reliable detection operation. In order to prevent, the second human body detection unit 42 is arranged at a position where a part of the human body 40 on the back cover 38, which is separated from the first human body detection unit 41 to some extent, is most easily approached.

6 (A), (B), and (C) are views for explaining the grip switch provided in the camera 37. The grip switch is arranged at a position where the photographer is supposed to hold the camera 37 at the time of photographing. The hold switch is provided, and as shown in FIG. 6 (A), it is arranged on a grip 37a that is gripped by the right hand 40A of the photographer. However, the photographer may be left-handed, or the holding method may be different from that shown in FIG. 6 (A). Therefore, a plurality of grip switches are provided at each position where the camera is supposed to be held, The operation of any one of these grip switches may be detected.

6B and 6C show an example of the grip switch, and the grip switch 59 shown in FIG. 6B is flexible so that the known mechanical contact 57 can be operated from the outside. It is formed by covering with the member 58. The grip switch 60 shown in FIG. 6 (C) is composed of a pressure sensitive rubber sensor, and conductor portions 62A and 62B sandwiching the pressure conductive rubber 61 sandwich the flexible outer surface 63 of the grip 37a of the camera 37. It is arranged in. In FIG. 6 (C), when the photographer holds the grip 37a of the camera and presses the grip switch 60, which is a pressure-sensitive rubber sensor, the conductivity of the pressure conductive rubber 61 increases, and the conductor portions 62A, 62B. The gaps become substantially conductive, and the grip switch 60 is turned on.

Next, the operation of the automatic focus adjustment system of the present invention configured as described above will be described with reference to the flowcharts of FIGS. 7 to 9.

7 and 8 show a first embodiment of the present invention,
FIG. 8 shows the general flow on the MAINCPU 14 side, and FIG. 8 shows the general flow on the AFCPU 22 side. First, a description will be given according to the flow of FIG.

Depending on the photographer, the camera side grip 37a (Fig. 6 (A))
(See), the signal from the grip switch interlocked with the grip is input to the MAIN CPU14.

Therefore, the AF power control unit of the MAIN CPU 14 shown in FIG. 2 becomes active "L", the transistor 23 is turned on, and the power supply voltage V _DD is supplied to the autofocus circuit unit. Even if the grip switch is not operated, this operation also occurs by operating the other operation switch including the force release, that is, the half-press operation of the release button. As a result, the AFCPU 22 is powered on and repeats the distance measuring operation. When the photographer starts looking through the viewfinder of the camera, the MAIN CPU14 receives a human body detection signal from the human body detection circuit 18 shown in FIG.
Send FENA “H”. This operation also occurs when the 1st.Rel signal is received. Then, the AFCPU 22 will immediately start driving the lens. AF operation is completed
When the MAINCPU 14 receives the AF end signal "EOFAF" from the AFCPU 22, the MAINCPU 14 waits for the input of the 2nd.Rel signal, that is, the deep release of the release button. That is, when the first "EOFAF" signal after apparently receiving the 2nd.Rel signal is received from the AFCPU 22, the process proceeds to the next exposure sequence. Then, the winding sequence is executed and the initial state is returned.

In the first embodiment, the AF sensor starts integration (starts distance measurement) immediately after the photographer grips the grip, and repeatedly executes integration and distance calculation. After that, when the photographer looks into the viewfinder, the lens drive is immediately started based on the distance measurement data calculated in advance.
AF drive continues as long as the photographer is looking through the viewfinder, and when the 2nd.Rel signal is accepted, the sequence immediately shifts to the exposure sequence. Therefore, an unprecedented breakthrough AF speed can be realized, and the time lag in AF can be almost ignored. In addition, from the MAIN CPU14 shown in FIG.
Input of the 1st.Rel signal to the PU 22 is unnecessary in this embodiment.

Next, the general flow of the AFCPU 22 will be described with reference to FIG. When the <AF> routine shown in FIG. 8 is started, the drive circuit of the autofocus circuit section is first initialized in the <I / O initialization> subroutine. Specifically, the AF display circuit 24, the motor drive circuit 26, the AF auxiliary light circuit 27, etc. are turned off and the MAINCPU 14 is turned off.
Initialize the serial communication line with.

Next, the control flag, register, and the like are cleared, and thereafter, the maximum value of the CCD integration time is set in the ITIME register so that CCD integration is reliably performed at a certain brightness or higher. Then, after turning off the auxiliary light and clearing the AF status flag described later, the defocus amount of the subject is calculated in the routine of <distance measurement>. After returning from the <distance measurement> routine, check the status of the AFENA signal,
If not "H", the AF status flag clearing operation and the <distance measuring> routine are executed again.

Here, the AF status flag will be described. The AF status flag is a flag that is set when it is not possible to focus, for example, in the <distance measurement> routine, where the condition of the subject is not enough to detect the defocus amount or the lens cannot be moved to the in-focus point. The low contrast flag (set when the subject has a low contrast, hereinafter abbreviated as LC flag) low light flag (set when the subject has a low brightness.
Abbreviated as LL flag. ).

In addition, the <distance measurement> routine performs integration of the CCD line sensor, calculation of the defocus amount, and calculation of the defocus direction.
It is stored in the ROR register each time. This routine has a function of appropriately changing the integration time according to the brightness of the subject.

The state of the AFENA signal is constantly monitored in the <distance measurement> routine. If the AFENA signal becomes “H” during CCD integration, one integration has already finished at this time and the ERROR register is defocused. If the amount data is stored, the process immediately returns from the <distance measuring> routine. On the other hand, if the data of the defocus amount is not stored, one integration is completed and the process returns.

After confirming "H" of the AFENA signal, next, the LL flag in the AF status flag is checked. If it is determined that the brightness is low, use of auxiliary light is permitted and distance measurement is performed again. If the brightness is not low, then proceed to check the LC flag. If it is determined that the contrast is low, <Lens scan>
In the routine of (3), the lens is forcibly moved from the current position to the closest position to the infinity position, and distance measurement is performed during that time to search for a position with low contrast.

When a position with low contrast is found or when the lens reaches the infinity position, the motor is stopped and the process returns from the <lens scan> routine.
After returning, the AFENA signal is checked, and if "H", distance measurement is performed again. If the AFENA signal is "L", it returns to the initial state.

If the distance measurement result is neither low brightness nor low contrast, then check whether the current lens position is in focus with the subject, that is, whether the defocus amount is within the predetermined allowable range. To do. here,
When it is determined that the lens is out of focus, the defocus amount is converted into the target movement amount (movement pulse number) of the lens in the <pulse calculation> routine. By the way, the comparison value for checking whether the calculated defocus amount is within the focusing allowable range differs depending on the open FNo. Of the lens. Therefore, in this embodiment, the threshold Eth of the autofocus accuracy is stored in the lens data circuit 17 arranged in the interchangeable lens, and this data is read at the time of focusing check. Further, the lens magnification coefficient for obtaining the target movement amount of the lens from the defocus amount is similarly stored in the lens data circuit 17.

After the target movement amount of the lens is obtained, it is then checked whether the lens is at the closest end to the position where it is currently stopped.
If not, proceed to the <MDRIVAF> routine, and if it is the closest end, check whether the direction to be driven is the closest direction. If the lens is in the close-up direction, it is naturally impossible to drive the lens.
Proceed to check the ENA signal.

On the other hand, if the driving direction is not the closest direction, the process proceeds to the <MDRIVAF> routine. The <MDRIVAF> routine is a subroutine for moving the photographing lens in the designated direction by the designated amount. When the lens reaches the target position, the routine returns from this routine. Further, in this routine, when the lens reaches the closest end and stops, the closest end stop flag is set and the process returns. In addition, AFENA even while driving the lens
The signal is monitored, and if the release button is half-pressed during driving, the operation returns immediately.

If the routine returns from the <MDRIVAF> routine, the procedure returns to and the distance measurement operation is performed again. This distance measuring operation is for confirming the focus after the lens is driven. If the focus is deviated from the focus permissible range, the lens is driven again and the loop until the focus is achieved is repeated. If it is determined to be in focus, the in-focus display is performed, and subsequently, the EOFAF signal of "H" is sent to the MAIN CPU 14 as a release permission signal. When the autofocus operation is completed, the AFENA signal is checked, and if it remains "H", this check operation is repeated and the next distance measuring operation is not started. In other words, AF
It will be locked.

In the first embodiment shown in FIGS. 7 and 8 above, 2nd.Rel
Since the AFENA signal is set to “L” after the signal is input, 2
Before the nd.Rel signal is input, that is, until the release button is fully pressed, the AF lock state does not exist, and the 8th
The <AF> routine in the figure is in operation.

Therefore, when the first EOFAF signal is received from the AFCPU22 after the MAINCPU14 receives the 1st.Rel signal, the MAINCPU14 side sets the AFENA signal to the "L" level to hold the AFCPU22 in the AF locked state. The system will be described below as a second embodiment of the present invention. In the second embodiment, the general flow on the MAINCPU 14 side is shown in FIG. 9, and the general flow on the AFCPU 22 side uses the same FIG. 8 as in the first embodiment.

In FIG. 9, when the photographer grips the grip of the camera, the power supply voltage V _DD is supplied to the autofocus circuit section, and the distance measuring operation is repeated. Then, when the photographer starts looking into the viewfinder of the camera, the MAIN CPU 14 receives the human body detection signal from the human body detection circuit 18, and sets the AFENA signal sent to the AF CPU 22 to "H". Then, the AFCPU22 immediately performs the AF operation, and when the AF operation ends, the EOF sent to the MAINCPU14 is sent.
Change the AF signal from "L" to "H". When the 1st.Rel signal supplied to the MAINCPU14 becomes active, the MAINCPU14
The AFENA signal is changed from "H" to "L" to the CPU 22, and this state is maintained until the 2nd.Rel signal becomes active. That is, the AF lock state is set. When the 2nd.Rel signal becomes active, it shifts to the exposure sequence, then executes the winding sequence and returns to the initial state.

By the way, although not shown in the above embodiment, when the photographer looks into the viewfinder, the lens drive is started, and once the focus is achieved, the AF threshold is set to 4 times in order to prevent unnecessary hunting. The lens drive is restarted only when the subject moves a lot, and in this case, when the 1st.Rel button is pressed, a sequence of finely adjusting the lens so that it stays within the AF threshold is adopted. Good. Even in such a case, the time lag will be greatly improved compared to the current situation.

In the present embodiment, as the focus detection means, the TTL method using the light passing through the taking lens has been described, but the focus detecting means is not limited to this, and is linked to the driving of the taking lens,
It should be added that any autofocus system in which the input to the focus detection means changes can be used in the same manner.

[Effects of the Invention] As described above, according to the present invention, when the photographer holds the camera, the focus detecting means starts to operate and the distance measuring operation is repeated, and as soon as the photographer looks into the viewfinder, Start driving the lens. Therefore, it is possible to dramatically reduce the time lag required for AF, and it is possible to provide an automatic focusing system having a minimum release time lag, which is a remarkable effect.

[Brief description of drawings]

1 (A) and 1 (B) are conceptual diagrams of an automatic focus adjusting system of the present invention, and FIG. 2 is a block diagram of an electric circuit mainly for supplying power in an embodiment of the automatic focus adjusting system of the present invention. FIG. 3 is a schematic block diagram showing signal transmission / reception of the autofocus circuit section in FIG. 2, FIG. 4 is a block diagram of the human body detection circuit in FIG. 3, and FIG. ) And (B) are side and rear views of the camera for explaining the arrangement position of the human body detecting section in FIG. 4, and FIGS. 6 (A), (B) and (C) are respectively. The front view showing the hold state of the camera, the sectional view of the camera grip showing an example of the grip switch, and the sectional view of the camera grip showing another example of the grip switch, FIG. 7 and FIG. Each operation of MAIN CPU and AF CPU in the embodiment Flowchart, Fig. 9 is a flowchart showing the operation of MAINCPU in the second embodiment of the present invention. 1 ... Shooting lens 2 ... Photoelectric conversion element 3 ... Holding detection means 4 ... Focus detection means 5 ... Control operation start means 6 ... Driving means 7 ... Drive control means 8 ... Human body detection means 14 ... MAINCPU (drive control means) 18 ...... Human body detection circuit (human body detection means) 20 ...... CCD line sensor (photoelectric conversion element) 22 ...... AFCPU (focus detection means) 26 ...... Motor drive circuit (drive means) 31 ...... Motor (driving means) 59,60 …… Grip switch (holding detection means)

Claims (3)

[Claims] 1. A driving means for electrically driving a focus adjusting lens, a focus detecting means for detecting a defocus amount of an image-forming position of an object with respect to a planned focus position, and a grip portion of a camera body for allowing a photographer to perform the above-mentioned operation. A holding detection unit that outputs a holding signal when holding the grip portion, a human body detection unit that outputs a human body detection signal by detecting that the photographer is looking into the eyepiece of the camera body, and the holding detection unit. Drive means for controlling the drive means based on the defocus amount detected by the focus detection means when the holding signal is output from the means and the human body detection signal is output from the human body detection means. An autofocus camera, characterized by comprising: 2. A human body detecting means for detecting that a photographer is looking into an eyepiece of a camera body and outputting a human body detection signal, and an image forming position of a subject while the human body detection signal is being output. Control means for repeating the operation of detecting the defocus amount with respect to the planned focus position and the operation of driving the taking lens based on the defocus amount, and synchronizing with the operation of detecting the defocus amount when the subject has low brightness. The projection means for projecting the auxiliary light to the subject and the projection of the auxiliary light until the release button of the camera is operated, and the auxiliary light is projected after the release button is operated. An automatic focusing camera, comprising: a projection control unit that permits the projection of the light. 3. A human body detecting means for detecting that a photographer is looking into an eyepiece portion of a camera body and outputting a human body detection signal, and a defocus amount of an imaging position of a subject with respect to a planned focal position. Defocus amount detecting means, driving means for driving a photographing lens based on the defocus amount detected by the defocus amount detecting means, and the defocus amount detecting means while the human body detection signal is being output. And a driving means for repeatedly operating the driving means, an operation detecting means for detecting whether or not the release button of the camera is operated by the photographer, and an operation detecting means for detecting the operation of the release button. , Automatic defocusing means for prohibiting detection of a new defocus amount and driving of the taking lens, and Mera.