JPH0782187B2 - Exposure meter that can display the number of shooting frames for movie cameras - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure meter, and more particularly to an exposure meter that performs exposure calculation based on exposure time information corresponding to a set number of movie camera shooting frames.

2. Description of the Related Art Conventionally, in an exposure meter in which the number of frames for movie cameras can also be set, a normal exposure time display corresponding to the shutter speed of the still camera (for example, ...
The scale of 60,125,250,500 ……) is marked, and the scale of the number of shooting frames is marked at the position corresponding to the exposure time on the side of such a normal exposure time display. Alternatively, the setting member is operated so that the scale of the exposure time display or the shooting frame number display corresponding to the number of frames matches the index.

However, in this type of exposure meter, there is a limit to the number of exposure time scales marked on the exposure time setting member, which causes a limit in the range of the set exposure time. In order to solve this, there has been proposed an exposure meter in which the set exposure time is stepwise changed according to the operation of the up / down key and the set exposure time is digitally displayed on the liquid crystal display device.

The problem to be solved by the invention is that a digital display pattern dedicated to the number of frames is required when the number of frames to be photographed is displayed in parallel with the exposure time display in an exposure meter that digitally displays the set exposure time by a liquid crystal display device or the like. Moreover, during the stepwise change of the set exposure time, an effective step occurs only for the number of frames. That is, for example, 18 frames per second have an exposure time of 1/36 seconds, and 24 frames per second have an exposure time of 1/48 seconds, which is effective as the number of frames but is not a step that is normally used as the set exposure time. Therefore, when the exposure time is set and used, unnecessary steps are passed.

The present invention provides an exposure meter that digitally displays the set exposure time and the number of frames to be photographed, the exposure time and the number of frames to be photographed can be easily set, and does not require a digital display pattern dedicated to the number of frames. It is an object.

Means for Solving the Problems In order to achieve the above object, in the present invention, the exposure time setting means has a step group of the number of frames to be photographed following the exposure time step group, and an up operation from the shortest set exposure time or a longest set exposure In response to the down operation from the time, the shooting frame number step group is set and the number of shooting frames for the movie camera is set, the exposure time display means displays the number of shooting frames, and the exposure calculation means corresponds to the number of shooting frames. It is configured to perform calculation based on time information.

Since the exposure time setting means is provided with a step group for the number of shooting frames following the exposure time step group, the exposure time and the number of shooting frames can be displayed using a common digital display pattern.
Easy to use without changing the exposure time setting.

Embodiment In FIG. 1, an exposure meter (1) comprises a light receiving window (2) for introducing light into a light receiving element (PD), a display section (4) for displaying on a liquid crystal device (LCD), a power switch (6), and a photometric meter. A button (8) and an exposure time setting operation member (10) are provided. The operating member (10) is supported so as to move between the UP position, the DOWN position, and an intermediate position between those positions, and is biased to the intermediate position.

FIG. 2 shows the circuit configuration of the exposure meter (1). A microcomputer (CPU) (hereinafter referred to as a microcomputer) has a photometric signal obtained by a photometric circuit (M) including a light receiving element (PD). The AD conversion circuit (AD) and the film sensitivity setting circuit (ISO) for A / D converting and outputting to the microcomputer (CPU) are connected. The photometry start circuit has a resistor (R1) connected to a normally open switch (SW1) and a predetermined power supply (VC), and an input terminal (I) of a microcomputer (CPU) via an AND circuit (AN1).
1) connected to. The exposure time setting circuit has the normally open switches (SW2) (SW3) and the resistors (R2) (R3) connected to the specified power supply (VC), and the input terminal () of the microcomputer (CPU) via the AND circuit (AN1). I2) (I3) is connected. The display driver (DV1) inputs the signal from the output terminal (O ₃ ) of the microcomputer (CPU) and controls the display state of the liquid crystal device (LCD). The microcomputer (CPU) further has a reset circuit (RE) that outputs a reset signal for performing a power-on reset of each circuit according to the ON operation of the power switch (6), and a reference pulse to the microcomputer (CPU). The oscillator (GE) to send is connected.

The switch (SW2) is closed when the operating member (10) moves in the UP position, and the switch (SW3) is closed when the operating member (10) moves in the DOWN position. Is configured. Switch (SW1) (SW2) or (SW
3) is closed, the input terminals (I1) (I2) or (I
The potential of 3) switches from the high level to the low level, the output of the AND circuit (AN1) changes from the high level to the low level, and the low signal is input to the input terminal (IT) of the microcomputer (CPU), As will be described later, the microcomputer (CPU) performs an interrupt operation.

FIG. 3 shows a part of a memory and a decoder inside the microcomputer (CPU), a display driver (DV1) and a liquid crystal device (LCD), and FIG. 4 shows a display pattern of the liquid crystal device (LCD). . Memory in the microcomputer (CPU) (CM1) (CM
2) The signals stored in (CM3) are output to the display driver (DV1) via the decoders (CD1) (CD2) (CD3) in the microcomputer, respectively, and the display driver (DV1) is decoder (CD1) ( Liquid crystal device (L
Display a predetermined pattern of CD). The memory (CM1) stores a time display control flag TCF for controlling whether the time information to be displayed is the normal exposure time or the number of shooting frames. That is, when the flag TCF stored in the memory (CM1) is 0, the TIME mark (a) indicating that the normal exposure time is displayed in FIG. Erase the CINE mark (b). When the flag TCF is 1, the TIME mark (a) is erased and CIN
Display the E mark (b). The memory (CM2) stores time information data (TM) as shown in Table 1. The decoder (CD2) causes the numerical value display shown in Table 1 to be displayed in the numerical value pattern (C) according to the value of the time data TM stored in the memory (CM2), and is 1 second or more when TM ≦ 10. The S mark (d) indicating that is turned on. The decoder (CD3) causes the pattern (F) to display an F number according to the value of the aperture value Avex data Av stored in the memory (CM3). When the under display control flag UNF or the over display control flag DVF stored in the memory (CM4) (CM5) becomes 1 (pattern)
Alternatively, the pattern (g) is displayed. It should be noted that the pattern (e) is always displayed by a configuration not shown when the power switch is in the ON position.

The value of the time data TM corresponds to the Avex value or Tv value of the exposure time as shown in Table 1. That is, as shown in the numerical display column of the table, when the time data TM is 5 to 10, the set exposure time corresponds to 30 seconds to 1 second, and the time data TM is
In 11 to 24, it corresponds to 1/2 to 1/8000 seconds, and in the case of time data TM 24 to 30, it corresponds to 8 to 64 seconds of shutter opening angle 180 degrees in the number of movie shooting frames. There is.

5 and 6 show flow charts showing the operation of the exposure meter.

When the power switch (6) is operated to the ON position and the power is turned on, a reset signal is input from the reset circuit (RE) to perform the RESET operation as shown in FIG. After initializing the stack pointer, etc. in step, in step, I from the ISO setting circuit is stored in the film sensitivity data memory Sv (not shown) in the microcomputer (CPU).
The SO information is fetched, initial data such as a value of 16 is input as the time data TM in the step, and data (blank data) for turning off all the patterns (f) is input in the memory (CM3) in the step. In the steps 1 to 3, the flags OVF, UDF, TCF and MEF are set to 0, and the memory for storing the photometric value Bv (not shown) is cleared in the step. In the step
The display program is executed to display the initial state, and at the step, the interruption by the input signal of the input terminal (IT) is permitted and the operation is stopped (step). At this time, among the display patterns shown in FIG. 4, the TIME mark (a), the numerical value of "60" in the pattern (c), and the FNo mark (e) are displayed.

When a Low signal is input to the input terminal (IT) by closing the switch (SW1), (SW2) or (SW3), the microcomputer (C
PU) executes the interrupt program shown in FIG. In the step, other interrupts are prohibited, and in the step, it is determined whether or not the switch (SW1) is closed. If YES, the process proceeds to step, where a photometry command signal is output from the output end (01), and photometry is performed by the photometry circuit (M). In order to convert the photometric value signal output from the photometric circuit (M) in the step to A / D conversion by the A / D conversion circuit (AD), A from the terminal (02)
Output the / D conversion signal. In the step, the circuit (A
In the step of waiting for the AD completion signal from D) to be input to the terminal (I4), the value of Bv based on the photometric value is input to the memory in the CPU. A flag MEF, which stores whether or not the photometry is performed in the step, is set to 1 and the fact that the photometry is performed is stored.

At step, the value of Tv corresponding to the time data TM shown in Table 1 is input, and at step, the aperture value Av of the aperture is obtained and the exposure calculation Av ← Bv + Sv−Tv is performed. In the step, it is judged whether or not the aperture value Av exceeds the maximum Av value that can be displayed. If not, that is, if YES, the process proceeds to the step, and the minimum Av that can display the Av.
If it is equal to or larger than the value, if it is YES, that is, if YES, the process proceeds to step and the F number corresponding to Av is displayed in the pattern (F). If Av exceeds the maximum Av value at the step, jump to the step and flag
In addition to inputting 1 into OVF, blank data is input into the memory that stores Av in the step, and the process proceeds to step to turn off the pattern (f) and turn on the O mark (h) which means over. On the other hand, if Av is smaller than the minimum Av in the step, jump to step 31 to set the flag UNF to 1 and enter blank data in the memory of Av in the step to proceed to the step to turn off the pattern (f). The U mark (g) indicating under is turned on.

In step, if the switch (SW1) is not closed and the result of the determination is NO, the process proceeds to step and it is determined whether or not the switch (SW2) is closed. If YES, it means that the exposure setting time has been increased, so proceed to step to judge whether TM is the maximum TM that can be set.If NO, proceed to step and set the value of time data TM. Increase by one. If YES, proceed to the next program without changing the value of time data TM. On the other hand, in the step, if the switch (SW2) is not closed and the determination result is NO, it is understood that the switch (SW3) is closed and the exposure setting time down operation is performed. In this case, it is determined whether or not the time data TM is the minimum TM that can be set, and if NO, the value of TM is decreased by 1. If YES, proceed to the next step without changing the value of TM.

In this way, when the exposure setting time is increased or decreased, the operation is performed according to the operation unless the time data TM exceeds the maximum or minimum value that can be set.
If you change the TM value and exceed the maximum and minimum values, leave the TM value as it is.

Next, in step, it is judged whether or not the time data TM is 24 or more. If it is more than 24, the time data TM has a value corresponding to the number of frames to be photographed as shown in Table 1, so the flag TC
When F is set to 1 and the CINE mark (b) is displayed in the step, and the time data TM is smaller than 24,
Flag because TM has a value corresponding to the set exposure time
Set TCF to 0 and set the TIME mark (a) at the step
To turn on. Flag in step
Judge whether MEF is 1 or not and see if the photometry has already been performed and the Bv value has been input. If YES, jump to the step, and based on the Tv value corresponding to the new TM, the exposure is performed in step or Repeat the calculation, and if NO, just change the exposure time setting before metering, so immediately jump to the step and update the value in pattern (C).
Change to one that supports TM, and turn on and off the TIME mark (a) and CINE mark (b) as necessary.

After the display is executed in the step, the interrupt is permitted in the step and the state is stopped in the step.

In this exposure meter, the exposure time and the number of shooting frames set as the value of TM are predetermined for each predetermined step as shown in Table 1, and the exposure time and the number of frames are continuously collected as a step group, A step group of the number of pieces is set following the end of the exposure time step group.

It should be noted that each setting range can be determined in addition to this embodiment, and a wider setting range can be set. The frame number step group may be set so as to follow the minimum Tv value, or a predetermined number of steps of blanks may be set between both step groups.

In the setting operation of the exposure time, in addition to the configuration of this embodiment, when the up operation or the down operation is continued, the value is changed step by step at a predetermined speed, and a so-called up / down switch is not used to rotate the operation member. The operation may be read using an encoder and the set value may be changed in the up direction or the down direction.

It should be noted that both ends of the set exposure time step group and the set shooting frame number step group may be made continuous so that both step groups are in a cycle.

EFFECTS OF THE INVENTION In the present invention, the set exposure time step group and the movie shooting frame number step group are separated, and both step groups are continued, so that both set values can be digitally displayed using common display means. At the same time, the setting operation is easy and the common operation member can be used.

[Brief description of drawings]

1 to 6 show an embodiment of the present invention.
FIG. 1 is an external front view, FIG. 2 is a circuit diagram, FIG. 3 is a circuit diagram showing a display driver, and FIG. 4 is an explanatory diagram showing a display pattern.
5 and 6 are flowcharts showing the operating state. SW2 ... Up operation switch, SW3 ... Down operation switch,
LCD ... Display device, M ... Photometric circuit.

Claims (2)

[Claims] 1. An exposure time setting means for stepwise changing the set exposure time in an up direction or a down direction in accordance with an up operation or a down operation, and an exposure time display means for digitally displaying the set exposure time. In an exposure meter provided with an exposure calculation means for performing calculation on the basis of exposure time information corresponding to the set exposure time, the exposure time setting means has a photographing frame number step group following the exposure time step group, and the shortest setting In response to an up operation from the exposure time step or a down operation from the longest set exposure time step, the process moves to the step of the number of frames for movie camera, and the display means digitally displays the number of frames to be shot, while the exposure calculation means , An exposure meter configured to perform calculation based on the exposure time information corresponding to the number of photographed frames. 2. The exposure meter according to claim 1, wherein the display means has an identification display means for displaying whether the digital display is a set time or the number of frames to be photographed.