JPH0827478B2 - Exposure control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control device for a camera, and more specifically, to determine a backlit state and to obtain an appropriate exposure amount for a main subject even in the backlit state. The present invention relates to an exposure control device for performing flash photography.

2. Description of the Related Art Japanese Patent Publication No. 55-29408 discloses that, in a camera having a spot metering device and an average metering device, when the difference between the spot metering value and the average metering value exceeds a predetermined value, it is determined that the backlight is in a backlit state. There has been proposed an exposure control device configured to cause a flash device to emit light to perform flash photography and perform so-called daytime synchronized photography.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in this conventional apparatus, when performing daytime synchronized photography, the exposure amount is determined based on the average photometric value, and the aperture value of the taking lens is determined according to this exposure amount. Then, flash photography is performed. Therefore, the determined aperture value and the amount of light emitted from the flash device determine the subject distance at which the proper exposure is obtained by the principle of flashmatic, and the proper exposure amount may not be obtained for the actual subject. is there.

Therefore, an object of the present invention is to provide an exposure control device that can always obtain an appropriate exposure amount for a subject regardless of the subject distance even when performing daytime synchronized photography.

Means for Solving the Problems In order to achieve the above object, the exposure control apparatus according to the present invention performs flash photography when the amount of exposure to the main subject is appropriate due to flash emission in the backlight state. At the same time, the exposure control is performed based on the photometric value obtained by averaging the brightness of the entire shooting range. On the other hand, when the exposure amount for the main subject is not appropriate due to the flash light, the exposure control is performed based on the photometric value for the main subject without performing the flash photography.

Whether or not the amount of exposure to the main subject is appropriate due to the flash light emission is determined by the aperture value, the distance to the main subject, and the amount of flash light emission that are determined according to the photometric value obtained by averaging the brightness of the entire shooting range. Is determined based on.

Therefore, according to the present invention, when the exposure amount for the main subject becomes appropriate by the flash emission, the main subject is made appropriate by the flash emission, and the background is exposed based on the photometric value obtained by almost averaging the brightness of the entire photographing range. Optimized by control. On the other hand, when the exposure amount for the main subject is not appropriate due to the flash light, the main subject is made proper by the exposure control based on the photometric value for the main subject.

Embodiment An embodiment in which the present invention is applied to a lens shutter camera will be described below with reference to the accompanying drawings. First, the principles of distance detection and brightness detection used in the embodiment will be described. This distance detection device includes a light projecting unit that emits light to the entire field of view for detecting a distance, a light receiving unit that receives light reflected from a subject, and a signal from the light receiving unit to process the subject. And a circuit for detecting the subject brightness.

Here, in the present embodiment, the light receiving means is composed of a plurality of light receiving elements, and the light receiving element is used for photographing by dividing the field into a plurality of areas and detecting the distances of the respective areas. An area at a certain distance, that is, a distance at which the photographing lens is focused, is detected, and the luminance of the area is detected assuming that the main subject exists in the detected area. That is, in the present embodiment, the light receiving means common to both the distance detection and the luminance detection is used.

The first specific example of the optical system sharing the light receiving means as described above
It will be described with reference to the drawings. (FL2) is an electronic flash device as the light projecting means, which irradiates light to the entire field through a filter (IRFI) provided on the front surface thereof for transmitting infrared light of a specific wavelength or wavelength range. . This electronic flash device (FL
The light intensity of 2) is much less than the light intensity of the electronic flash device for illuminating the subject used for shooting. (LE) is a condenser lens that collects the light reflected from the subject (OB) and guides it to the light receiving device (SPC). Between this lens (LE) and the light receiving device (SPC), a specific wavelength or wavelength A filter (LCDFI) configured to be switchable between a filter that transmits infrared light in the region and a filter having a characteristic of visibility is provided.

This filter (LCDFI) may be constructed, for example, as shown in FIG. Ie this filter (LCDFI)
Is a guest-host type liquid crystal (LCD1) and (LCD2), and is a microcomputer (MC) shown in FIG.
When a "High" level (hereinafter "H") signal is output from a terminal (OP1) (hereinafter referred to as a microcomputer), a predetermined voltage V2 is supplied to a first liquid crystal (LCD1) via a buffer (BuF). )
Applied to the first liquid crystal (LCD1), the first liquid crystal (LCD1) transmits infrared light having a specific wavelength or wavelength range. On the other hand, when a "Low" level (hereinafter "L") signal is output from the output terminal (OP1) of the microcomputer (MC), the second liquid crystal (LCD2) is passed through the buffer (BuF) and inverter (IN1). ) To the specified voltage V2
Is applied, the second liquid crystal (LCD2) operates as a luminosity filter that transmits light in the luminosity region. The buffer (BuF) and the inverter (IN2) are configured to be powered by a power supply voltage (V2) described later,
Therefore, when a release button (not shown) is not pressed, no voltage is applied to both liquid crystals (LCD1) (LCD2) and the liquid crystal is in a colorless light transmitting state.

The light-receiving device (SPC) shown in FIG. 1 is composed of a plurality of light-receiving elements as described above, and is adapted to measure each of a plurality of areas of the field-indicated by a square frame in FIG. There is. Then, as shown in FIG. 3, the plurality of light receiving elements are arranged so as to measure an area that is biased slightly downward in the shooting range as a whole, and the light receiving elements that measure slightly below the center of the shooting range are centered, A total of 9 units including this light-receiving element are arranged symmetrically in the left-right and up-down directions, and the distance detection and the luminance detection from the measurement area shown by the hatched portion are performed. In this way, the reason why the entire measurement area is located slightly below the shooting range (field of view) is that in a lens shutter camera with a relatively wide-angle shooting lens, an object or person considered as the main subject is shot. This is because it does not exist so much at the upper part of the range and often exists at the lower part.

Next, a camera system that performs the above-described distance detection and brightness detection will be described.

In the block diagram of FIG. 4 showing an outline of the circuit configuration of the entire camera, (E) is a power battery, and two lithium batteries having an open circuit voltage of 3 V are used.

(D1) is a diode that prevents the power supply voltage to the microcomputer (MC) from decreasing when the booster circuit in the electronic flash device (FL) is driven. (C0) is a capacitor that is provided to prevent noise and to quickly charge the main capacitor in the electronic flash unit (FL), and (C1) is a capacitor with a relatively large capacity for backing up the microcomputer (MC). , (R1) and (C2) are reset resistors and capacitors for resetting the microcomputer (MC) when the power supply battery (E) is installed. (SW) is a switch group having a plurality of switches required for operating the apparatus of this embodiment,
The details will be described later with reference to FIG.

(DI) is a display circuit for displaying shooting information, and (FI) is the second
The liquid crystal filter shown in the figure serves as an infrared filter or a visible light filter as described above.

The microcomputer (MC) is for controlling the entire circuit. (IS) is a microcomputer (MC) that converts the film sensitivity read from the code pattern provided on the film container or the manually set film sensitivity into a film sensitivity value converted to an apex value, that is, a speed value (SV).
The film sensitivity setting circuit (LM) that outputs to (2) receives the light emitted from the electronic flash unit (FL2) for distance measurement (hereinafter referred to as AF), which is described later, and reflected from the subject, and detects the distance to the subject. This is a distance measuring / photometering circuit that consists of a distance measuring circuit and a photometric circuit that measures the brightness (BV) of the subject. (AE) is an exposure control circuit that controls the exposure based on the exposure value (EV) output from the microcomputer (MC). This circuit (AE) sends a light emission start signal () to the electronic flash unit (FL) at a predetermined timing. X1) is output. (AFC) is an AF control circuit that drives the taking lens to a predetermined position based on AF data indicating the subject distance output from the microcomputer (MC), and (MO) is a motor (M) that winds the film. It is a motor control circuit for controlling.

(FL) is an electronic flash device, which is an electronic flash device for distance measurement (FL
2) and an electronic flash device (FL1) for illuminating the subject during shooting. (Tr1) is turned on according to the signal from the microcomputer (MC), and when turned on, the filter (FI), film sensitivity setting circuit (IS), distance measuring / photometering circuit (LM), exposure control circuit (AE) , AF control circuit (AFC), and motor control circuit (M
O) is a transistor that supplies power to each.

FIG. 5 shows a specific example of the switch group (SW) in FIG. (S0) is ON in conjunction with opening and closing the lens cover (not shown)
This is a lens cover switch that is turned on / off. A circuit configured by a delay circuit (DEL) and an exclusive OR circuit (EOR) according to ON / OFF of this switch (S0) is an interrupt terminal of a microcomputer (MC). A pulse signal is output to (INT0).
The microcomputer (MC) executes a predetermined interrupt routine (INT0) when this pulse signal is input to its interrupt terminal (INT0). (S1) is a shooting preparation switch that turns on when the release button (not shown) is pressed down to the first stroke. If this switch (S1) is turned on while the lens cover is open, the interrupt routine (INT1) is executed. It (S2) is a release switch that is turned on when the release button is pressed down to the second stroke deeper than the first stroke. (S3) is an exposure completion switch, which is turned off in response to the completion of charging of the shutter mechanism by a shutter charging member (not shown) that charges the shutter mechanism to the initial state, and is turned off in response to completion of the exposure operation.
N will be done.

(S4) is a single-frame winding switch, which is turned off in response to the completion of the exposure operation, and O when the single-frame winding of the film is completed.
N will be done. (S5) is turned on when the taking lens is extended to a predetermined position according to the control signal, and is turned off when charging of the shutter mechanism by the shutter charge member is completed.
It is a switch that is used.

Next, details of the distance measuring / photometering circuit (LM) used in the present embodiment for performing distance detection and luminance detection will be described with reference to the block diagram of FIG.

(LM1) to (LM9) are the measurement areas shown in FIG.
It is a distance measuring / photometering circuit for detecting the distance and detecting the brightness. Of these, the circuit for distance detection is a timing circuit that generates a signal so that the signal from the light receiving element is latched at the timing when the intensity of light emitted from the electronic flash device (FL2) becomes almost maximum in the change. The signal from the light receiving element, that is, the distance signal is latched in accordance with the signal (TM), and this signal is output to the selector (SEL).
The selector (SEL) selects the signals from the distance measuring / photometering circuits (LM1) to (LM9) according to the signal from the decoder (DE2) that decodes the signal from the microcomputer (MC), and outputs them to the encoder (ED). . The encoder (ED) encodes the input signal into a predetermined signal and outputs it to the microcomputer (MC). Therefore, the distance signals from the distance measuring / photometering circuits (LM1) to (LM9) are sequentially output to the microcomputer (MC) via the selector (SEL) and the encoder (ED) by the signal from the microcomputer (MC).

On the other hand, the brightness signal indicating the brightness of the subject output from the distance measuring / photometry circuits (LM1) to (LM9) is output to the analog switch (ANSW) as an analog signal. This analog switch (ANSW) is composed of 9 FETs, and these FETs are connected to the distance measuring / photometering circuits (LM1) to (LM9) respectively so that the luminance signal of each area is input, All outputs are integrated into a single A / D conversion circuit (A / D
D) is connected to. This analog switch (ANSW)
Is selected by the signal of the decoder (DE2) which decodes the signal from the microcomputer (MC) as in the case of the distance signal. That is, nine distance measuring / photometering circuits (LM
FETs connected to 1) to (LM9) are sequentially selected by the microcomputer (MC), and each distance measuring / photometering circuit (LM1) to
Analog signals corresponding to the subject brightness measured by (LM9) are sequentially output from the analog switch (ANSW). The luminance signal output to the A / D conversion circuit (A / D) via the analog switch (ANSW) is converted into a digital signal by this A / D conversion circuit (A / D), and then converted to a microcomputer (MC). Is output.

Details of the distance measuring / photometering circuit (LM1) and the timing circuit (TM) in the above block diagram will be described with reference to FIG. In FIG. 7, a portion surrounded by a dotted line is a timing circuit, and the other portions are a distance measuring / photometering circuit (LM1).
First, the timing circuit (TM) will be described. When a release button (not shown) is pressed, a signal of "H" is output from the terminal (OP8) of the microcomputer (MC) and the transistor (Tr2) is turned on before the electronic flash device (FL2) for distance measurement emits light. And discharge the charging charge of the timing capacitor (C3). Immediately before the electronic flash device for measuring distance (FL2) emits light, the transistor (Tr2) is turned off and waits for light emission. The phototransistor (PHT that charges this capacitor (C3)
1) is arranged near the light emitting part of the electronic flash for distance measurement (FL2) and directly receives the emitted light.
When the electronic flash device (FL2) emits light in this state, a current corresponding to the intensity of light is charged in the timing capacitor (C3) through the phototransistor (PHT1), and the charging voltage of this capacitor (C3) is the reference voltage. When (Vr1) is exceeded, the comparator (COMP1) is inverted and outputs the "H" signal. This "H" signal is pulsed by the one-shot circuit (OS1), and the D flip-flop (DF
It is input to the terminal (T) of F1) and the first light receiving element (SPC
Latch the amplified signal from 1). Here, the above-mentioned reference voltage (Vr1) is applied to the comparator (COMP) when the light emission intensity of the electronic flash device (FL2) is slightly decreased from the maximum.
1) is determined to be reversed.

Next, the distance measuring / photometering circuit (LM1) will be described. By pressing the first stroke of the release button, a voltage is applied to the power supply line V2, and power is supplied to each circuit. Then, the "H" signal is immediately output from the terminal (OP9) of the microcomputer (MC), the analog switches (AS1) (AS2) are both turned on, and the constant current from the constant current sources (I1) (I2) Each comes to flow. Here, the constant current from the constant current source (I1) is I1, and the constant current from the constant current source (I2) is I2. The distance measuring / photometering circuit (LM1) becomes stable after a lapse of a predetermined time after the analog switches (AS1) (AS2) are both turned on. (In this embodiment, at least 20 msec is applied to that time.) Briefly explaining the circuit operation until this circuit (LM1) stabilizes, the constant current sources (I1) (I2) generate constant currents I1 and I2. When it started flowing, the transistor (Tr3) did not turn on because the voltage of the capacitor (C4) (hereinafter, this capacitor is called the steady light capacitor) was very low, and it passed through the constant current I1 and the filter. The photocurrent IP corresponding to the brightness of light of a specific wavelength flows to the base of the transistor (Tr4) and is amplified here. This amplified current flows from the transistor (Tr6), and the same current also flows from this transistor (Tr6) and the transistor (Tr7) connected to the current mirror. Part of this current becomes the current of the constant current source (I2), and the remaining current is the diode (D2) (D3).
Flows to As a result, at the non-inverting input terminal (+) of the operational amplifier (OP1), a voltage (VD) corresponding to two diode stages corresponding to the photocurrent IP and the constant current I1 is generated. The operational amplifier (OP1) has a reference voltage (Vr2) at the inverting input terminal (-), and a voltage (V
D) is input and negative feedback is applied to the transistor (Tr3) so that this voltage (VD) is always constant.

Now, the current flowing out of the transistor (Tr7) is a current obtained by amplifying almost all of the photocurrent IP and the constant current I1, so the diode 2 generated by this current
The voltage for the steps (VD) is higher than the reference voltage (Vr2). Therefore, the operational amplifier (OP1) charges the stationary light capacitor (C4) in order to raise the base voltage of the transistor (Tr3). Where this capacitor (C4)
Is charged through the transistor (Tr4). And
When the voltage of the constant light capacitor (C4) rises and the transistor (Tr3) turns on, the constant current I1 and the photocurrent IP flow through the collector of the transistor (Tr3), so the base current flowing in the transistor (Tr4) Decrease. As a result, the current flowing through the transistor (Tr6) and the transistor (Tr7) decreases, and the voltage (VD) for two diode stages drops. Then, the above-described operation is performed until the voltage (VD) for two diode stages becomes equal to the reference voltage (Vr2). During this operation (during a transient phenomenon), the voltage (VD) for two diode stages may become lower than the reference voltage (Vr2). At this time, the operational amplifier (OP1) turns on the steady light capacitor (C4). ) Of the transistor (Tr3), the current that draws in the constant current I1 and photocurrent IP of the transistor (Tr3) is reduced, and the transistor (Tr3) is reduced.
4) Base current increases. Therefore, the transistor (T
The current flowing through r6) (Tr7) increases and the voltage (VD) for two diode stages rises.

With the above operation, this circuit is stable, a current almost equal to the sum of the constant current I1 and the photocurrent IP flows in the transistor (Tr3), and the voltage of the steady light capacitor (C4) is the same as the constant current I1. It is the base voltage of the transistor (Tr3) according to the sum of the photocurrent IP.

When the electronic flash device for distance measurement (FL2) is caused to emit light in such a state, the reflected light reflected from the subject is input to the light receiving element (SPC1), and is converted into reflected light from the subject that includes ambient light. Corresponding photocurrent IP ′ (current due to the above-mentioned steady light component
In order to distinguish it from IP, it will be referred to as IP 'hereinafter). Of these, the photocurrent IP of the stationary light component flows through the collector of the transistor (Tr3), and the current IP'-IP corresponding to the reflected light.
Flows as the base current of the transistor (Tr4).
At this time, the capacitance of the capacitor (C4) is determined so that the transistor (Tr4) does not respond to the photocurrent during the period when the reflected light from the subject is input to the light receiving element (SPC1). Then, this photocurrent IP 'is amplified by the transistor (Tr4) and flows through the transistors (Tr6) (Tr7) to the diodes (D2) (D3). This raises the voltage (VD) for two diode stages, and this voltage (VD)
Is compared with a reference voltage defined by a constant current I3 of a constant current source (I3) and resistors (R11) to (R14), and distance (zone) information is represented as outputs of comparators (COMP2) to (COMP5). The output signals of the comparators (COMP2) to (COMP5) are latched by the D flip-flops (DFF1) to (DFF4) by the signal from the timing circuit (TM), and the latched signals are output to the selector.

After distance measurement is performed as described above, the light receiving element (SP
The filter before C1) is switched from a filter that passes infrared light of a specific wavelength to a luminosity filter. Furthermore, the constant current source (I1) is turned off to eliminate the voltage for the constant current I1 with respect to the charging voltage of the constant light capacitor (C4), and
The constant current source (I2) is turned off, the feedback path of the transistor (Tr3) by this constant current I2 is turned off, and the voltage of the capacitor (C4) depends on the brightness of the constant light flowing from the light receiving element (SPC1). Just try to be. Then, this voltage is output to the analog switch (ANSW) via the buffer (BuF1).

The other photometric circuits (LM2) to (LM9) shown in FIG.
The configuration is exactly the same as that shown in the figure.

Next, the electronic flash device for photography (FL
The configuration of 1) and the electronic flash device (FL2) for distance measurement will be described with reference to FIG. The electronic flash device for distance measurement (FL2) has a very small amount of light emission (about 1/25 of the maximum light emission amount) compared to the electronic flash device for shooting (FL1), except for the circuit configuration. Since the device is exactly the same as the device (FL1), its circuit is simply shown as a block, and the description of its specific configuration is omitted.

In the circuit of the electronic flash device for photography (FL1), (DCC)
Is a step-up control circuit, which controls the step-up control transistor (Tr8) according to the step-up control signal (FLC1) from the microcomputer (MC) and the charge completion signal (B.C1) described later, and the step-up circuit (D
Control the boost operation of C). (DC) is a booster circuit, (D4)
Is the rectifier diode, (BC) is the main capacitor (C5)
Is a charge detection circuit for detecting the state of charge of, and (EC) is a light emission control circuit that causes a xenon tube (Xe) to emit light in response to a light emission signal (X1) from an exposure control circuit (AE) to cause flash light emission. The light emission signal (X2) of the electronic flash for distance measurement (FL2)
Is sent from the microcomputer (MC) via the buffer (BuF10).

The operation of the electronic flash device for photographing (FL1) will be described. The charging completion signal (B.C1) is "L" when the charging of the main capacitor (C5) is not completed. In this state, when the "L" boost control signal (FLC1) indicating the start of boosting is sent from the microcomputer (MC), the NOR circuit (NOR1) outputs the "H" signal and the boost control circuit (DCC ) Is input to the boost control circuit (DCC), the transistor (Tr
Controls 8) to turn on to start boosting operation of the booster circuit (DC). Then, the charging of the main capacitor (C5) is completed and the charge completion signal (B.C1) becomes "H", or the boost control signal (FLC1) from the microcomputer (MC) becomes "H".
Then, the NOR circuit (NOR1) outputs "L", which causes the boost control circuit (DCC) to switch the transistor (Tr8) to OF.
F to control to stop boosting. When the charging of the main capacitor (C5) is completed, the neon tube indicating this state is turned on regardless of the boost control circuit (DCC) and the microcomputer (MC).

Next, the flow of the entire camera in the embodiment will be described. Before that, the number of distance zones for detecting whether or not the subject is in the distance zone in the distance measuring apparatus used in the embodiment, and The focusing distance range in the zone and how to determine it will be described.

The distance measuring device of the embodiment detects the distance by the absolute amount of the reflected light from the subject as described above. However, since the reflectance differs depending on the subject, the distance detected by the distance measuring device does not necessarily match the distance to the subject.
In the present embodiment, the focusing distance range of each distance zone is widened or the focusing distance range extending over two distance zone areas is provided so that the subject can always be in focus even in such a case. ing. However, with such a method, the distance range from the closest distance of the taking lens (for example, 0.6 m) to infinity is set to 5 distance zone regions with the taking lens diaphragm open (F3.5 in the embodiment). It is impossible with the performance of a normal lens to always obtain the in-focus state with respect to the subject. In view of this, in this embodiment, the open aperture that can be used by the taking lens is limited to the small aperture side as the distance increases, and the focusing range is widened to a specific area.
The focus state is always obtained in only one distance zone area. As a result, in the case of a shutter that also serves as an aperture, when the aperture is made small, the shutter speed also becomes faster, so there is a drawback that the brightness range in which natural light photography without illuminating the subject by the electronic flash device can be narrowed, resulting in insufficient exposure. Therefore, in this embodiment, in such a case, an electronic flash device is used to perform flash photography to compensate for this. The lens-combined shutter used in this embodiment is
The time-varying characteristic of the opening degree is a type showing a triangular waveform, and when it gradually opens in response to a series and reaches a predetermined aperture value, it shifts to a closing operation.

FIG. 9 shows the five distance zone areas and the focusing distance ranges in each of the distance zone areas, the maximum aperture value at that time, and the aperture value at the time of flash photography, which are implemented based on the above idea. To do.

In the figure, the vertical axis indicates the distance zone area, which is the distance zone areas 1, 2, 3, 4, 5 in order from the short distance side. The horizontal axis represents the distance to the subject, which is from 0.6m to ∞. Explaining the focusing distance range of each distance zone area, in area 1, the open aperture value is F8, the focal position of the lens is 0.75 m,
The focus distance range is 0.56m to 1.1m. In Region 2, the maximum aperture value is F5.6, the focus position is 1.0m, and the focusing distance range is 0.77.
m-1.5m, in area 3 the aperture value is F4 and the focus position is
1.5m, the focusing distance range is 1.1m to 2.2m, the open aperture value in the areas 4 and 5 is the open aperture value F3.5 of the taking lens, the focus position is 2.1m in the area 4, and the focus distance range is 1.5m. m-3.6m, area 5
Then, the focus position is set to 5 m and the focusing distance range is set to 2.7 m to ∞.

In FIG. 9, FM represents the aperture value in the case of flash photography using an electronic flash device.

Next, a method of deciding the aperture at the time of flash photography with such a design will be described. It is assumed that the flash device has a guide number of 10 for a film sensitivity of 100. Then, as F13 in region 1, if a short distance end of (distance to the object is 0.56 m) becomes the exposure value E _V is one step over, in the case of long-distance (distance to the object is 1.1 m) the exposure value E _{The V} is designed to be one step under. In the same way, for areas 2, 3, 4, and 5, the aperture is set to over or under by the same exposure value at both the near and far end of the focusing distance range of each area. The values are determined respectively, and in area 5, the maximum aperture value is set to F3.5 so that the flash emission light reaches as far as possible so that flash photography can be performed. In FIG. 9, FM indicates the aperture value (F number) in each region at the time of flash photography, which is determined in this way.

10 to 14 are flowcharts showing the operation of the microcomputer (MC), and the control operation of the camera will be described with reference to the flowcharts.

First, the operation when the battery (E) is mounted will be described with reference to FIG. When the battery (E) is installed, a signal that changes from "L" to "H" is input to the reset terminal (RES) of the microcomputer (MC), and the microcomputer (MC) starts the flow from the battery installation (step # 0). To execute. In this flow, first, in step # 5, the microcomputer (MC) prohibits all interrupts to this flow, and in step # 10, the output terminals and registers of the microcomputer (MC) are initialized. Then step # 15
Input the signal of the terminal (IP6) with to allow the interrupt, and in step # 20 determine whether the lens cover is open or not based on whether the lens cover switch (S0) is ON or not, and close it. If so, the process proceeds to step # 25 to prohibit the interrupt to the interrupt terminal (INT1), which will be described later, and stops at step # 27. On the other hand, when the lens cover is open (when the lens cover switch (S0) is ON), the process proceeds from step # 30 to step # 45 described later.

Next, an interrupt routine (INT0) executed when the lens cover is opened / closed will be described. If the lens cover is opened or closed while interrupts are permitted in this flow, a pulse signal will be input to the interrupt terminal (INT0) of the microcomputer (MC), and the microcomputer (MC) will Execute the operation of the interrupt routine (INT0) from # 32. First step # 35
Check if the lens cover is opened or closed from the state of the lens cover switch (S0). If the lens cover is closed (lens cover switch (S0) is OFF), go to step # 57. Then, the interrupt routine (INT1) described later is prohibited from interrupting the flow, and the process proceeds to step # 60. The switch (S0) was turned on in step # 35,
That is, when the lens cover is open, the interruption to the interruption terminal (INT1) of the microcomputer (MC) is permitted in step # 40, and the electronic flash device for distance measurement for photographing (# 45, # 50). To start boosting FL1) (FL2), output "H" signals from the output terminals (FLC1) (FLC2) of the microcomputer (MC), and in step # 55, the electronic flash device (FL1) for photography The charge completion signal (B.C1) is input to determine whether the main capacitor (C5) has been charged. It should be noted that if the lens cover is open when the battery is attached, the process also goes to step # 45. When it is determined in step # 55 that the main capacitor (C5) has been charged, the boosting of both the electronic flash devices (FL1) (FL2) for shooting and distance measurement is stopped in steps # 60 and # 65. In order to do so, the microcomputer (M
C) outputs an “L” signal to the output terminals (FLC1) (FLC2). Then, at step # 70, all the flags of the microcomputer (MC) are reset, at step # 75 the timer that was being timed by the interrupt routine (INT1) described later is stopped, and at step # 80 it is displayed. Off, step # 85
To stop the operation.

Next, when the release button is pressed to the first stroke with the lens cover open, a signal that changes from "H" to "L" is input to the interrupt terminal (INT1) of the microcomputer (MC), (MC) executes the flow of the interrupt routine (INT1) from step # 90 in FIG.

In this flow, first, in step # 95, the step-up of the electronic flash device (FL1) for photographing is stopped in order to detect the distance and the luminance, and the noise due to the drop and the step-up of the battery voltage is prevented. Next, in step # 100, the transistor (Tr
1) is turned on to supply power to each control circuit, etc., and in step # 105, the analog switches (AS1) (AS2) are turned on and the constant current sources (I1) (I2) for distance measurement are turned on respectively. In step # 110, the terminal (OP1) is set to "H" so that the filter is switched to infrared for distance measurement. Then, in step # 115, the timer for circuit stability is reset and started, and in step # 120, the timing transistor (C3) that determines the timing for latching the output of the distance measuring / photometering circuit is discharged in order to discharge the timing transistor ( Turn on Tr2).

Next, in step # 125, the electronic flash device (FL2) for distance measurement
Control is started to start boosting, and in step # 130, the completion of charging the light emitting capacitor is waited. When this charging is completed, the boosting is stopped in step # 132. And
In step # 135, it is determined whether 20 msec has elapsed from the start of the timer. If it has not elapsed, wait for it to elapse, and if it has elapsed, turn off the timing transistor (Tr2) in step # 140. . And step #
In order to detect the distance to the subject with 145, output "H" to the terminal (X2) and let the electronic flash device (FL2) for distance measurement emit light, and in step # 150 check whether the distance measurement data has been latched. The signal from the timing circuit is input and detected, and the distance measurement data is waited for to be latched. If it is detected in step # 150 that the ranging data is latched, step #
We proceed to 155 and detect the terminal (O) of the microcomputer (MC) for brightness detection.
P1) to "L" to make the filter for visual sensitivity, and in step # 160 turn off the analog switches (AS1) (AS2),
In step # 165, the process proceeds to the "AF data" subroutine for fetching the latched data for distance measurement in preparation for brightness detection.

The details of the "AF data" subroutine will be described with reference to FIG. 12. First, in steps # 1000 to # 1010, the microcomputer (MC) sets variables (N) (N1) (N2) to 0, respectively, and in step # 1015. Set the variable (D0) to 5. Then, in step # 1020, the set variable (N) is set to the sixth value.
Output to the decoder (DE2) shown, step # 1025
Input the output data (D1) of the encoder (ED), which encodes the distance measurement data from the distance measurement / photometry circuit selected by the selector (SEL) that received the output of the decoder (DE2) into a predetermined code. This data (D1) is a value corresponding to the distance zone areas 1 to 5 (for example, if the distance zone area is 1
If so, the data (D1) is also 1, and if the distance zone area is 5, the data (D1) is also 5).

Based on the data (D1) input to this microcomputer (MC), in the following flow, each light receiving element (SPC1) to (SPC9)
Based on the output of, the distance measuring / calculating circuits (LM1) to (LM9) determine which distance zone area each of the distance measuring data is calculated. First, in step # 1030, it is determined whether the variable (D0) set to 5 in step 1015 and the input data (D1) are equal to each other so as to correspond to the distance zone area 5 indicating the longest distance. # 1035 adds 1 to the variable (N1). N1 is a variable for determining whether the number of light-receiving areas in the closest distance area is singular or plural. Then, in step # 1040, the input data (D1) is set as this variable (D0), and in step # 1040
At 45, add 1 to the variable (N) (N = 2). On the other hand, when the variable (D0) and the input data (D1) are not equal in step # 1030, the process proceeds to step # 1050 and the input data (D1)
1) is a variable (D0) that indicates the farthest distance zone area 5
It is determined whether or not it is the closer distance zone area. If it is not the closer distance zone area (D0 <D1), the process proceeds to step # 1045, and the closer distance zone area is indicated (D0> D1). ) If so, go to step # 1055 for variable (N1)
Is set to 1, and the variable (N2) is set to the variable (N) in step # 1060 (N2 = 0), and the flow proceeds to step # 1040.
N2 indicates a light receiving area, and a value obtained by subtracting 1 from the smallest area number among the light receiving areas indicating the shortest distance is set. After adding 1 to the variable (N) in Step # 1045 (N = 2), this variable (N) is added in Step # 1065.
Is 9 or not, that is, 9 light receiving elements (SPC1)
It is determined whether all the ranging data corresponding to the output of (SPC9) have been input. If not, the process returns to step # 1020 to repeat this loop. And step # 10
When N = 9 in 65 and the input of the distance measurement data is completed, the process proceeds to step # 1067 to return to the original flow of step # 165 in FIG. 11 and proceed to the next "photometric data" subroutine.

This "photometric data" subroutine is shown from step # 1070 in FIG. 12, and in this step # 1070, the variable (N1) is 1, that is, the subject corresponds to the closest distance in the nine measurement areas. It is determined whether the number of measurement areas determined to be in the distance zone area 1 is single,
If the number is singular (N1 = 1), the flow proceeds to the "spot photometry" subroutine of step # 1075. When there are a plurality of measurement areas in which it is determined that the subject exists in the distance zone area corresponding to the closest distance (N1 ≠ 1), the process proceeds from step # 1070 to step # 1080, and the variable (N2) Is determined to be 0, it is determined whether or not the measurement region corresponding to the central portion of the photographing range is included in the plurality of measurement regions. When this region is included (N2 = 0), Also proceeds to step # 1075.

On the other hand, when the central measurement area is not included (N2
≠ 0), the average photometry flag (AVRF) in step # 1085
After setting, proceed to the "average photometry" subroutine in step # 1090, and in step # 1095, use the average photometry value (BV
2) is used as photometric data (BV) and the procedure returns to the original flow in step # 1100.

The "spot photometry" and "average photometry" subroutines in this "photometry data" subroutine will be described with reference to FIG. First, the subroutine of "spot metering" will be described. In step # 1160, the microcomputer (MC) sets a variable (N
2) is output to the decoder (DE2). Then, the decoder (DE2) decodes this and measures the distance indicated by the variable (N2).
One of nine FETs of the analog switch (ANSW) is turned on so that the analog signal indicating the subject brightness detected by the photometric circuit is output to the A / D conversion circuit (A / D). Then, in step # 1165, the microcomputer (MC) converts the analog signal into a digital signal by using the terminal (OP
The A / D conversion start signal is output from 6), and in step # 1170, it is determined whether or not this A / D conversion is completed by the signal of the terminal (OP7). Furthermore, if the A / D conversion operation by the A / D conversion circuit (A / D) is completed, the microcomputer (MC) will execute A / D conversion in step # 1175.
The D end signal is output from the terminal (OP6), and the photometric data indicating the subject brightness converted into the digital signal in step # 1180 is captured as the photometric data (BV).

Next, the "average photometry" subroutine will be described. First, in steps # 1105 and # 1110, a variable (BV2) indicating the average photometry value and a variable (I) indicating one of the nine distance measuring / photometry circuits. To 0, and step # 11
At 15, this variable (I) is output to the decoder (DE2). Similar to the case of spot metering described above, steps # 1120 to #
At 1130, the analog signal indicating the subject brightness detected by the distance measurement / photometry circuit corresponding to this variable (I) is A / D converted at the A / D conversion circuit (A / D), and this photometry is performed at step # 1135. Input the data to the microcomputer (MC) as photometric data (BV1). Further, in step # 1140, this photometric data (BV1) is added to the variable (BV2) set to 0 in step # 1105, and in step # 1145, 1 is added to the variable (I). Then, in step # 1150, it is determined whether the variable (I) has become 9, and if it is 9, there are nine distance measuring / photometering circuits (LM1).
Assuming that the photometric data indicating the subject brightness has been input from all of (LM9) to (LM9), the process proceeds to the next step # 1155. If the photometric data is not 9, the process returns to step # 1115 to repeat this loop and input the photometric data. . After inputting all data, the microcomputer (MC) proceeds to step # 11.
In 55, the photometric data (BV2) obtained by adding all the data corresponding to the subject brightness measured by each of the distance measuring / photometry circuits (LM1) to (LM9) is divided by 9, and the average brightness data of the subject (BV2) Ask for. Here, as a variable example of the present embodiment, when there are a plurality of light receiving elements used for distance measurement, a photometric value obtained by averaging all the areas may be always used regardless of the light receiving elements that look at the area from the center. For this
In the flowchart of FIG. 12, step # 1080 may be deleted.

When the "photometric data" subroutine of Fig. 12 is completed,
The operation of the microcomputer (MC) returns to the flowchart in FIG. In step # 175 of FIG. 11, the film speed data is sent from the film speed setting circuit (IS) to the apex value (SV).
In step # 180, the exposure value (EV) is obtained by adding the photometric data (BV) to this value (SV).

Next, the exposure value (EV) for switching between natural light photography and flash photography, which changes depending on the distance zone area in which it is determined that a subject is present, will be described. Step # 185
In, it is determined whether or not the area where the subject is present is the distance zone area 1 corresponding to the shortest distance. If it is zone 1, the process proceeds to step # 190 and the exposure value (EV) calculated in step # 180. Is 13.5 or more. If the exposure value (EV) is less than 13.5, step # 235
Fix the exposure value (EV) to 13.5 and proceed to step # 270. Similarly, in step # 195, it is determined whether or not the area in which it is determined that the subject is present is the distance zone area 2. If the area is zone 2, the process proceeds to step # 200 and the exposure value (EV) is 11.5 or more. It is determined whether or not. When the exposure value (EV) is less than 11.5, the process proceeds to step # 230 to fix the exposure value (EV) to 11.5. In addition, step # 20
In 5, it is determined whether or not the area in which it is determined that the subject exists is the distance zone area 3, and if it is in zone 3, step #
Proceeding to 210, it is determined whether the exposure value (EV) is 9.5 or more. Then, when the exposure value (EV) is less than 9.5, the process proceeds to step # 225 to fix the exposure value (EV) to 9.5. If the area in which it is determined that the subject is present is the distance zone area 4 or 5, the process proceeds from step # 205 to step # 215 to determine whether the exposure value (EV) is 8.5 or more. And when the exposure value (EV) is less than 8.5,
Fix the exposure value to 8.5 in step # 220. From these steps # 220, # 225, # 230, and # 235, the process proceeds to step # 270, and the electronic flash device (FL1) enters the flash photography mode in which the subject is illuminated and the subject is photographed.

In contrast, when the distance zone area where the subject is present is zone area 1, the exposure value (EV) is 13.5 or more, when the distance zone area 2 is the exposure value (EV) is 11.5 or more, and when the distance zone area 3 is If the exposure value (EV) is 9.5 or more and the exposure value (EV) is 8.5 or more when the distance zone area is 4 or 5, proceed to step # 240 to see if the average photometry flag (AVRF) is set. Is determined. here,
If the average photometry flag (AVRF) is not set, the process proceeds to step # 245 and "average photometry" shown in FIG.
Metering data of average metering by executing a subroutine (BV2)
In step # 250, the difference between the photometric data (BV2) and the spot photometric data (BV) is determined, and this difference is defined as photometric difference data (BV3) (BV3 = BV2-BV). Further, in step # 255, it is determined whether or not the photometric difference data (BV3) is 2EV or more. And this photometric difference data (BV
If 3) is 2EV or more, it is determined that the backlight is in a state where the brightness difference between the average photometric value and the spot photometric value is large, and it is determined in step # 26.
At 0, the daytime sync flag (FILE) is set and the process proceeds to step # 270 to enter the flash photography mode.

Average photometric flag (AVRF) in step # 240 above
Is set, or if the metering difference data (BV3) is less than 2EV in step # 255 and the difference between the average metering brightness value and the spot metering brightness value is less than 2EV, proceed to step # 265. The process proceeds to step # 390, which will be described later, to calculate the aperture value (AV), and then to the release flow.

Next, the flash photography mode from step # 270 will be explained. In step # 270, the electronic flash device for photography (FL1)
It is determined whether or not the charging of the main capacitor has been completed, and if completed, the process proceeds to step # 310 to display the completion of shooting preparation. If the charging of the main capacitor of the electronic flash device for photographing (FL1) is not completed in step # 270, the release button is pressed to the first stroke and the photographing preparation switch (S1) is turned on in step # 275. If the switch (S1) is ON, it is displayed in step # 280 that the electronic flash device (FL1) has not been charged, and the release button is released to prepare for shooting. Wait for switch (S1) to turn off.

Then, when the release button is not pressed down to the first stroke and the shooting preparation switch (S1) is turned off, the microcomputer (MC) turns off the transistor (Tr1) in step # 285.
When set to F, power supply to the control circuit and the like is cut off, and in step # 290, boosting of the photographing electronic flash device (FL1) is started. Then, in step # 295, the timer for battery check is reset and started, and in steps # 300 and # 305, it is determined whether or not the charging of the main capacitor is completed within 10 seconds from step # 295, and charging is performed in 10 seconds. If is not completed, the power source is exhausted, and the process proceeds to step # 320 to stop boosting. Then, in step # 325, the warning display timer is reset and started, and then in step # 330.
Then, the battery check warning is issued for 5 seconds at # 335, the display is turned off at step # 340, the flag is reset at step # 345, and the operation is stopped at step # 350.

If the main capacitor is completely charged within 10 seconds from step # 295, the power is not exhausted.
The process proceeds from step 300 to step # 310 to display the completion of shooting preparation, and then proceeds to step # 355 in FIG.

In step # 355 of FIG. 14, the aperture value (AV1) in the flash photography mode is calculated based on the following equation.

AV1 = 2.5 + DV + (SV-5) where DV is 5,4,3,2,1 corresponding to the distance zone areas 1,2,3,4,5 where the object is determined to exist Is.
For example, the amount of light emitted by the electronic flash unit (FL1) is always constant, and now, for film sensitivity ISO = 100, the guide number
Suppose it is 10. In this case, the area where the subject is determined to be present is the distance zone area 2, and when the film sensitivity of the film used is ISO = 100, DV and SV are 4 and 5, respectively, and the calculated aperture value (AV1) becomes 6.5, and when converted to F number, it becomes F / 9.3.

Next, in step # 357, it is determined whether the calculated aperture value (AV1) is less than 3.5. If it is less than 3.5, it is fixed in step # 360 and fixed in step # 362. move on.

Then, in step # 362, the daytime sync flag (FIL
F) is set to determine whether it is the daytime sync mode, and if this flag is not set and the daytime sync mode is not set (FILF = 0)
Is the aperture value (AV) for exposure control based on the following formula from the exposure value (EV) fixed by each zone in step # 365.
Is calculated, and the aperture value (AV1) data indicating the light emission timing of the flash light emitting device (FL1) is output in step # 385.

AV = 3.5 + (EV-8.5) / 2 In step # 362, the daytime sync flag (FILF) is set to 1, and in daytime sync mode, proceed to step # 370 and average based on the following formula. Obtain the aperture value (AV2) in the average metering mode from the metering data (BV2) of the metering value.

AV2 = 3.5 + {(BV2 + SV) -8.5} / 2 Then, in step # 375, the aperture value (AV2) thus calculated and the aperture value (AV1) in the flash photography mode described above.
Compare with This is to determine whether or not the light emitted from the electronic flash device (FL1) provides an appropriate exposure amount for the main subject in the daytime sync mode.

More specifically, during daytime synchronization photography, the background is generally exposed based on illumination with natural light, and a person is illuminated with an electronic flash device to correct the insufficient exposure due to the natural light. Therefore, when using an electronic flash device that determines the aperture value in natural light shooting mode and uses the aperture value to maintain a constant light emission amount, it is not possible to determine whether the exposure amount for the main subject at a predetermined distance is appropriate due to the flash emission light. The aperture value (AV1) calculated in the flash photography mode and the aperture value (AV) calculated in the natural light photography mode may be compared. With the shutter that also functions as an aperture, the aperture opens from small aperture to gradually open, and flash photography can be performed at any timing during the opening. Then, it can be said that the exposure amount of the main subject becomes appropriate by the flash emission light when the electronic flash device (FL1) emits light. That is, when the aperture value (AV1) calculated in the flash photography mode is equal to or greater than the aperture value (AV) calculated in the natural light photography mode (when the aperture is the same or a small aperture), proper daytime synchronized photography can be performed. .

In daylight sync mode like this, step # 380
Then, the microcomputer (MC) uses the aperture value (AV2) for average photometry as the control aperture value (AV), and outputs the aperture value (AV1) data as the light emission timing data of the flash light emission in step # 385.

Further, in this embodiment, if the main subject does not reach the proper exposure amount due to the flash photography even in the backlit state, the procedure proceeds from step # 375 to step # 388, and the following formula is calculated based on the photometric data in the spot metering. Natural light photography is performed using the control aperture value (AV).

AV = 3.5 + (EV-8.5) / 2 Further, in step # 390, the microcomputer (MC) determines whether or not the release switch (S2) is turned on by the release operation, that is, by pressing the release button up to the second stroke. If it is determined that the release operation has not been performed, the process proceeds to step # 395 to determine whether or not the shooting preparation switch (S1) is turned on to determine whether or not the release button has been pressed down to the first stroke. If so, return to step # 390 and wait for the release operation.
When the release button is not pressed down to the first stroke in step # 395 (when the switch (S1) is OFF), the process proceeds to step # 450 described later.

If it is determined in step # 390 that the release operation is being performed, the microcomputer (MC) enters the release control operation, first prohibits the interrupt to this flow in step # 392, and measures the distance measurement data in step # 400. (AF data) to A
It is sent to the F control circuit (AFC), and in step # 405, a start signal for starting the driving of the taking lens is output to the AF control circuit (AFC). When the photographic lens is driven to the specified position based on the above data, the switch (S5) indicating the completion of AF control is turned on.
This causes the microcomputer (MC) to
Detects completion of F control. Next, in step # 415, the microcomputer (MC) outputs the data of the control aperture value (AV) to the exposure control circuit (AE), and in step # 420, outputs the AE control start signal to the exposure control circuit (AE). Exposure control circuit (AE)
Then, when the flash emission timing data at the time of flash photography is sent from the microcomputer (MC), the electronic flash device for photography (FL1) at a predetermined timing based on that data.
The light emission signal (X1) is output to.

When the exposure control circuit (AE) controls the exposure and the exposure completion switch (S3) turns ON, step # 42.
Detect it in 5 and proceed to step # 430, step #
At 430, the motor (M) is driven to wind the film one frame, and when it is detected in step # 435 that the film has been wound by one frame, the motor (M) is stopped in step # 440. Let

Then, in step # 445, the microcomputer (MC) permits the interrupt to this flow, and in step # 450, the power supply to the control circuit is turned off. Then, in preparation for the next shooting, in steps # 455 and # 460, the electronic flash device for shooting and distance measurement (FL
1) Start boosting (FL2), reset and start the boost control timer in step # 470, then step # 47
In 2 and # 475, if the charging of the main capacitor is completed within 5 seconds or if 5 seconds elapse, the boosting of each electronic flash device (FL1) (FL2) is stopped in steps # 480 and # 485, and the step The display is turned off at # 490, all flags are reset at step # 495, and the microcomputer (MC) stops its operation at step # 500.

Although the first embodiment based on the present invention has been described above, in the above-described embodiment, the distance zone area indicating the shortest distance among the detected distance zone areas is set as the distance zone area for photographing. However, in the second embodiment described below, weighting is performed for each distance measuring / device circuit when obtaining the distance zone area in which it is determined that a subject is present, and the weighted value is calculated for each distance zone area. In addition, it detects which distance zone region has the highest frequency.
If the distance between the detected distance zone area and the distance zone area having the shortest distance among the detected distance zone areas is one, it means that the subject exists in the intermediate distance zone area. to decide. For example, distance zone area 3
Is detected as the most frequent distance zone area, and the distance zone area 1 is detected as the shortest distance zone area, the image is taken with the distance zone area 2 intermediate between the distance zone area 1 and the distance zone area 3. The distance zone for On the other hand, when the distance is other than the above, the closest distance zone area is set as the distance zone for photographing. The brightness detection and the backlight detection are the same as those in the first embodiment.

15 and 16 show a flowchart of the operation of the microcomputer (MC) which executes this second embodiment. This flowchart shows steps # 165 and # 170 shown in FIG.
A modified example of the "AF data" subroutine and the "photometric data" subroutine is shown, and the overall flow is exactly the same as in FIGS. 11, 13, and 14.

The flow chart will be described below. In FIG. 15, first, the microcomputer (MC) executes steps # 1500 to # 1510.
Then, the variables (N0) to (N4) (N10) to (N14) and (N) are set to 0, respectively. Then, in step # 1515, the microcomputer (MC) outputs the set variable (N) to the decoder (DE2). In step # 1520, the microcomputer (MC) outputs the distance measurement data (D1) from the predetermined distance measurement / photometry circuit. To enter. Here, each of the distance measuring / photometering circuits (LM1) to (LM9) includes a group 1 including the distance measuring / photometering circuits (LM1), a group 2 including the distance measuring / photometering circuits (LM2) to (LM5), and Distance measurement
The photometric circuits (LM6) to (LM9) are divided into three groups, which are groups 3, and the groups 1, 2, and 3 are respectively weighted with 3, 2, and 1. Here, each of the distance measuring / photometering circuits (LM1) to (LM9) has a light receiving element (SPC1) to (SPC9) which is focused on the measurement region shown in FIG.
Are processed respectively. Therefore, the measurement area is weighted by 3 and the measurement area by is weighted by 2.
Is weighted to 1.

To explain this weighting, if there is a measurement area (N = 0), proceed from step # 1525 to step # 1530 to set this input data (D1) as a variable (D2), and weight it at step # 1535. Data α is 3. Similarly, if the measurement area is from step # 1540 to step #
Step 1545 is proceeded to, and the weighting data α is set to 2, and if the measurement region is to, steps # 1540 to # 1550 are proceeded to and the weighting data α is set to 1.

Next, the microcomputer (MC) adds, for each distance zone area, the total number of measurement areas belonging to the distance zone area and the weighting data. When the distance zone areas detected in the measurement areas are 1, 2, 3, 4, and 5, the weighting data α is added to the variables (N0) (N1) (N2) (N3) (N4), respectively. (N10) (N11) (N12) (N
13) Add the number of measurement areas to (N14) (# 1555 to 164)
0). Then, in step # 1645, 1 is added to the variable (N), and it is determined in step # 1650 whether this variable (N) has become 9. If it is not 9, the process returns to step # 1515 and the variable (N) is returned. ) Repeats to 9, and if it is 9, it is assumed that all the ranging data has been input, and the microcomputer (MC) proceeds to step # 1655 to find the distance zone area including the most frequent ranging area. .

First, in step # 1655, the value of the variable (N0) indicating the added value of the weighting data of the distance zone area 1 is moved to N5,
Next, in step # 1660, the distance zone area is set to 1 in the variable (D3).
Is input, and the variable (I) is set to 1 in step # 1665. Next, the variable (N5) indicating the added value of the weighting data and the variable (NI) (I is the above variable) are compared (for example, if I = 1, the weighting data corresponding to the distance zone area 2 is calculated). If the variable (N5) that shows the added value is compared with the variable (N1) and the variable (NI) is larger than the variable (N5), proceed to step # 1675 and proceed to the variable (N
The value of 5) is changed to a variable (NI), and the distance zone area I at that time is input to (D3) in step # 1680.

Even when the variable (NI) is less than the variable (N5) in step # 1670, the process proceeds to the next step # 1685 and the variable (I) is set to 1
And in step # 1690 this variable (I) is set to 5
Is determined, and if it is not 5, step #
Return to 1670.

If the variable (I) becomes 5 in step # 1690, the microcomputer (MC) proceeds to step # 1695 in FIG. 16 and proceeds to step # 1695 to indicate the shortest distance zone area among the detected distance zone areas. , And the distance between the distance zone area and the most frequent value of the distance zone area, and the distance zone area for photographing is obtained.

Steps # 1695, # 1710, # 1725 and # 1740 of FIG. 16
In, the microcomputer (MC) sequentially inspects 1 to 4 in the distance zone area, and the distance in which any of the variables (N0) (N1) (N2) (N3) indicating the value of the weighting data is not 0 Find Zone Area, Steps # 1700, # 1715, #
Variable (N0) (N1) (N2) (N3) with 1730 or # 1745
Input the data indicating the distance zone area at the time when any of the above is no longer 0 to the variable (D0), and further, step # 17
A variable (N10) (N11) (N12) that indicates the number of measurement areas in the distance zone area on 05, # 1720, # 1735 or # 1750
Input either (N13) into the variable (N7).

Then, in the case where the distance zone area indicating the shortest distance among the detected distance zone areas is 1 to 3, the variable (D
0) indicates either zone 1, 2, or 3. In this case, in step # 1765, it is determined whether or not the interval between the variable (D0) indicating the distance zone area and the variable (D3) indicating the most frequent distance zone area is 1. If the interval is 1, the data of the intermediate distance zone area is input to the variable (D0) in step # 1770, and the process proceeds to step # 1775 of the "photometric data" subroutine.

On the other hand, when the detected closest distance zone area is 4 or 5, the most frequent distance zone area is also 4 or 5, and therefore the distance between the two does not become 1. Therefore, step # 1745. Alternatively, in # 1755, enter the data indicating the zone area into the variable (D0), and in step # 1750 or # 1760, set one of the variables (N13) (N14) indicating the number of measurement areas in the distance zone area to the variable ( Enter N7) and immediately proceed to step # 1775.

Compared to the one shown in FIG. 12, the "photometric data" subroutine from step # 1775 shows that in step # 1775, the variable (N1) in step # 1070 in FIG. 12 is (N7).
The contents processed by the microcomputer (MC) are exactly the same, except for the change to.

Although the embodiment based on the present invention has been described above, the present invention is not limited to this, and the following modifications are also possible.

(1) In both the first and second embodiments, when the number of the measurement areas in which the distance zone area that indicates the shortest distance among the detected distance zone areas is detected is plural, the central measurement area is included. The photometric data when not measured was based on the average of all measurement areas regardless of the distance zone area.In this case, the brightness detected by all the measurement areas that detected the distance zone area showing the shortest distance. You may take the average of. For this purpose, the number of the measurement area in which the distance zone area indicating the shortest distance is detected is stored, the brightness of the measurement area is input based on this number, and the average thereof is calculated.
Also, regardless of the central measurement area, if there are multiple measurement areas that have detected the distance zone area indicating the shortest distance,
You may take the average value of the photometric value of this some measurement area.

(2) In the first and second embodiments of the present invention, the electronic flash device provided separately from the electronic flash device for photographing is used as the distance projecting means, but this electronic flash device for photographing is used. May be shared. In this case, a filter for transmitting only infrared light of a specific wavelength may be arranged on the entire surface of the light emitting unit at the time of distance measurement, and a mechanical mechanism for retracting the filter at the time of photographing may be provided. Further, the light projecting means is composed of a plurality of light emitting diodes (LE) as disclosed in JP-A-59-146032.
D) may be used, or one light emitting diode may be sequentially scanned.

(3) When the backlight condition is detected, in the above embodiment, if the exposure amount of the main subject is not proper only by flash photography, the flash photography mode is switched to the natural light photography mode, and the natural light photography mode is changed from the average photometry. I switched to spot metering. However, even if the exposure amount of the main subject is not always appropriate, the film has a latitude range, and the image of the subject can be reproduced as long as it is within that range. Specifically, with regard to film, even if the exposure value (EV) is under 1.5 steps from the proper exposure value, it is a range that can be sufficiently covered by the above latitude, so the exposure amount of the main subject is appropriate with only the flash light. The exposure amount (E
It may be possible to illuminate the subject up to about 1.5 steps under V).

(4) Further, (1) to (3) of the modified examples may be appropriately combined with the first and second embodiments.

Effects of the Invention As described in detail above, the exposure control apparatus according to the present invention performs flash photography when the amount of exposure to the main subject becomes appropriate due to flash emission in the backlight state, and at the same time, the exposure range of the entire photography range is reduced. The exposure control is performed based on the photometric value obtained by almost averaging the brightness. On the other hand, when the exposure amount for the main subject is not appropriate due to the flash light, the exposure control is performed based on the photometric value for the main subject without performing the flash photography.

Whether or not the amount of exposure to the main subject is appropriate due to the flash light emission is determined by the aperture value, the distance to the main subject, and the amount of flash light emission that are determined according to the photometric value obtained by averaging the brightness of the entire shooting range. Is determined based on.

Therefore, when the exposure amount for the main subject becomes appropriate due to the flash emission, both the main subject and the background become appropriate. On the other hand, even when the exposure amount to the main subject is not proper due to the flash light, at least the main subject is proper.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a distance measuring / photometric optical system used in an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of a transmission wavelength switching type liquid crystal filter, and FIG. 3 is a photometric / ranging area. 4 is a block diagram showing a circuit configuration of an embodiment of the present invention, FIG. 5 is a circuit diagram showing a concrete example of the switch group in FIG. 4, and FIG. 6 is FIG. More detailed block diagram of the photometry / distance measurement circuit, FIG. 7 is a circuit diagram showing a concrete example of the photometry circuit and timing circuit in FIG. 6, and FIG. 8 is a block diagram showing an example of the circuit configuration of the electronic flash device. Fig. 9, Fig. 9 is a graph showing the relationship between subject distance area, focusing range and aperture value, Figs. 10 to 14 are flow charts showing the operation of the microcomputer of Fig. 4, and Figs. 6 is a flowchart showing a second embodiment for determining a distance area for (LM) (LM1) to (LM9): first photometric means, second photometric means, distance measuring means, (FL) (FL1): flash light emitting means, (M
C): Backlight judging means, first exposure calculating means, second exposure calculating means, judging means, (MC) (AE): exposure controlling means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Otsuka 2-30 Azuchi-cho, Higashi-ku, Osaka City, Osaka Prefecture Osaka International Building Minolta Camera Co., Ltd. Kiyonobu Kitagawa Examiner

Claims (1)

[Claims] Claim: What is claimed is: 1. A first photometric means for measuring a relatively wide area of a photographing range to calculate a first photometric value which is an average of the brightness of the entire photographing range, and a second photometric value for a main subject. Second light measuring means, distance measuring means for measuring the distance to the main subject, flash emitting means for emitting light for flash photography, and backlight determination for determining whether or not the main subject is in a backlit state Means, a first exposure calculation means for calculating a first exposure value consisting of a combination of an aperture value and an exposure time based on the first photometric value, and an aperture value based on the second photometric value. A second exposure calculation unit that calculates a second exposure value that is a combination with an exposure time, and an aperture value that is determined according to the first exposure value when performing flash photography, Measured distance to the main subject and amount of light emitted by the flash light emitting means Based on the above, the determination means for determining whether or not the exposure amount for the main subject is appropriate by the flash emission means, and the determination amount for the main subject by the determination means for the backlight emission condition when it is determined to be in the backlight state. Is determined to be appropriate, flash photography is performed using the flash emission means, and the exposure operation is controlled based on the first exposure value.
If the determination means determines that the exposure amount for the main subject is not appropriate by the flash emission means, the exposure control means controls the exposure operation based on the second exposure value without performing flash photography. A characteristic exposure control device.