JPS645685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an exposure control device for flash photography that enables flash photography taking into account the brightness of stationary light.

BACKGROUND ART Conventionally, devices have been proposed that control the amount of light emitted by a flash light emitting device based on signals of the distance to a subject and a set aperture value. Furthermore, a device that controls the diaphragm based on signals representing the distance to the subject and the amount of light emitted from a flashlight emitting device is well known as a flash-machine device.
These devices perform exposure control on the assumption that the amount of ambient light incident on the subject is very small compared to the amount of incident light from the flashlight emitting device and can be ignored.

However, there are not always subjects for which the incident light due to constant light can be ignored, and sometimes subjects for which ignoring the incident light due to constant light will result in an overexposed photograph.

In addition, in conventional devices, when performing flash photography, the ratio of the amount of contribution of steady light to the amount of flash light to photography (the difference between the apex value of the amount of contribution of steady light and the apex value of the amount of light due to flash), that is, the lighting
It was impossible to take pictures that took contrast into consideration.

Furthermore, with conventional devices, it is also possible to take into account the apex value, which indicates how much the brightness of the subject differs between shooting using only steady light and flash photography, which is hereinafter referred to as step difference. It was impossible.

Purpose/Summary of the Invention The object of the present invention is to propose a new flash photography device that enables flash photography that was impossible with conventional devices such as those described above.

This invention proposes a device that controls the amount of flash light emitted based on the subject distance, set lighting contrast, set exposure control value, and brightness of stationary light.

The present invention also proposes a device that controls the amount of flash light emitted based on a subject distance, a set difference in the number of steps, a set exposure control value, and constant light.

Embodiments Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

First, the principle of this invention will be explained. If the flash output of the flash light emitting device is P, the apex value of the film sensitivity is SV, and the guide number is G, then the relationship G=a・√2 ^SV・……(1) (a: constant) is established, where Guide number is SV=
Since the value is 5, it becomes G=a・√2 ⁵・ ...(1-1). On the other hand, the apex value AVf of the aperture value determined by the subject distance L and the amount of flash light emitted, the amount of light emitted by the flash device α・G (α is a variable), and the apex value SV of the film sensitivity is √2 ^AVf・L=( α・G)・√2 ^SV-5 ...(2) There is a relationship between the apex value QVf of the amount of light incident on the subject due to flash and the apex value AVf of the aperture value: QVf + SV = AVf ...(3) _Since there ^is _a relationship ^between = 1/2 (QVf+5) + log ₂ L...(2-2)
The relationship holds true. Therefore, if the subject distance L and the amount of incident light QVf due to flash light to the subject are known in advance, the amount of light emission (α・G) or log ₂ (α・G) can be calculated, and if the amount of light emitted is controlled based on this value, the apex value of the amount of light incident on the subject due to the flash is
QVf, the amount of incident light is 2 ^QVf .

On the other hand, the apex value of the subject brightness according to the incident light formula is BVa, the apex value of the total amount of light incident on the subject during flash photography is QVt, the exposure time is TV,
When the aperture value is AV, the following relationship holds true: 2 ^AV = 2 ^SV 2 ^QVt = 2 ^SV 2 ^QVf + 2 ^BVa-TV ) ...(4). Further, the lighting contrast Δ ₁ is expressed as Δ ₁ =QVf−(BVa−TV) (5), and the step difference _Δ2 is expressed as _Δ2 =QVt−(BVa−TV) (6).

First, when exposure TVs and lighting contrast Δ ₁ are set, the amount of incident light QVf due to flash is determined from equation (5) as QVf = Δ ₁ + (BVa − TVs) (5-1). From this value and distance L, (2-
2) The amount of light emitted by the flashlight emitting device can be controlled according to the formula. Furthermore, using equation (5), from equation (4), (BVa−
TVs), 2 ^AVx = 2 ^SV・2 ^QVf・(1+2 ^- 〓 ¹ ) ...(4-1), and taking log ₂ on both sides, the aperture value AVx is AVx = QVf + SV + log ₂ (1 + 2 ^- 〓 ¹ )...It is determined by (7). In addition, equation (4) can also be transformed as 2 ^QVt = 2 ^BVa-TVs・(1+2〓 ¹ )...(4-2), and by this equation, Δ ² = QVt-(BVa-TVs)=log ₂ ( 1+2〓 ¹ ) ...(6-1) is obtained, and the difference in the number of stages Δ ₂ is also found.

When the aperture value AVs and lighting contrast Δ ₁ are set, first transform equation (4) using equation (5), then 2 ^AVs = 2 ^SV・2 ^QVf・(1+2 ^- 〓 ¹ )...( 4-3), and the amount of light incident on the subject from the flash is QVf=AVs-SV-log ₂ (1+2 ^- 〓 ¹ )...(8). Therefore, from this value and the subject distance L, (2
-2) The amount of flash light can be controlled by formula. Further, the exposure time TVx can be calculated from equation (5) as TVx=Δ ₁ +BVa−QVf (5-2), and the step number difference Δ ₂ can be obtained from equation (6-1).

When the exposure time TVs and step number difference Δ ₂ are set, transforming equation (4) using equation (6) gives 2 ^QVf = 2 ^BVa-TVs・(2〓 ² −1) ……(4-4 ), and by taking log ₂ on both sides, QVf=BVa−TVs+log ₂ (2〓 ² −1) ……(9) The amount of light incident on the subject due to flash light can be obtained. On the other hand, the aperture value AVx is obtained by the formula AVx=QVt+SV=BVa+SV+Δ ₂ −TVs (10). Further, the lighting contrast Δ ₁ can be found by transforming the equation (6-1) as follows: Δ ₁ =log ₂ (2〓 ² -1) . . . (6-2).

When the aperture value AVs and the step number difference Δ ₂ are set, TVx = BVa + Δ ₂ −QVt = BVa + Δ ₂ − (AVs − SV) ...(6-3) is obtained from equation (6). On the other hand, the amount of light QVf incident on the subject due to flash light is obtained from equation (9) as QVf = BVa - TVx + log ₂ (2〓 ² -1) ... (9-1), and the lighting contrast Δ ₁ is (6 - 2) Determined from the formula.

Next, the amount of light incident on the subject due to flash QVf,
When the exposure time TVs is set, the amount of flash light is controlled from this set value QVf and the distance L. Also, the lighting contrast Δ ₁ is found from equation (5), Δ ₁ =QVf−(BVa−TVs)...(5) The step difference Δ ₂ is found from equation (6-1), and the aperture value AVx is ( 7) Determined from Eq.

Amount of light incident on the subject due to flash QVf and aperture value
When AVs is set, first define Δ ₃ ≡ AVs − AVf ... (11) = AVs − (QVf + SV) and transform equation (4) using equation (11), then 2 ^AVs ( 1-2 ^- 〓 ³ ) = 2 ^BVa+SV-TVx ...(4-5) From this formula, TVx = BVa + SV-AVs-log ₂ (1-2 ^- 〓 ³ ) = TVa
-log ₂ (1-2 ^- 〓 ³ ) ...(12) is obtained, and the exposure time TVx is determined. Further, the lighting contrast Δ ₁ can be found from equation (5), and the step number difference Δ ₂ can be found from equation (6-1).

Note that the photometry circuit of a normal camera is a reflected light type, so in order to convert the output BVa' of this photometry circuit into a value of the incident light type, it is necessary to perform the calculation BVa = BVa' + k...(13) . Here, k is a constant corresponding to the average value of the reflectance of the object, and the reflected light is reduced by the reflectance of the object compared to the incident light.

Further, the signal of the subject distance L may be obtained from a known distance detection device or a member linked to lens focus adjustment.

FIG. 1 is a block diagram showing a first embodiment of the invention. SE ₀ is a setting device that outputs data corresponding to lighting contrast Δ ₁ , SE ₂
is a setting device that outputs data corresponding to step number difference Δ ₂ , SE ₄ is a setting device that outputs data corresponding to aperture value AVs, SE ₆ is a setting device that outputs data corresponding to exposure time TVs, SE ₈ is a setting device that outputs data corresponding to film sensitivity SV. LM is a photometering circuit that measures ambient light using reflected light.AD is an A-D converter, and DI is a distance detector that outputs data corresponding to the subject distance L or a lens focus adjustment position signal output device. It is a signal output device. AL is an arithmetic circuit, CA is an aperture control device, DS is a display device, CT is a shutter control device, and DA is a D-A converter.

ST is a flashlight emitting device, and terminals J ₂₁ and J ₂₀ on the camera side are connected, and terminals J ₁₁ and J ₁₀ are connected. Inside the flashlight emitting device ST, there is a signal output circuit SO that outputs a "high" signal when preparation for emitting light is completed, and a light emission control circuit that controls the amount of light emitted based on the signal from the D-A converter DA. We are prepared.

Next, the operation will be explained. Switch SW ₀ is “ON”
, and when a "high" signal is input from the signal output circuit SO, and switch SW ₂ is "ON", AND gate AG ₂ outputs the set number of stages from setting device SE ₂ . Data with a difference Δ ₂ is output. At this time, the output of the inverter IN ₀ is "low", so the gate of the AND gate AG ₀ is closed and the output becomes 0. On the contrary, switch
When SW ₂ is “OFF”, the gate of AND gate AG ₀ is opened, and the set writing contrast Δ ₁ data from setting device SE ₀ is output from AND gate AG ₀ , and AND gate AG ₂
The output of is 0. In addition, when switch SW ₀ is "OFF" or when a "high" signal is not output from the signal output circuit SO, both gates of AND gates AG ₀ and AG ₂ are closed, so both gates The output of is 0.

When switch SW ₄ is "ON", the gate of AND gate AG ₆ is opened and the gate of AND gate AG ₄ is closed. Therefore, and gate
From AG ₆ , set exposure time TVs from setting device SE ₆
The data corresponding to is output and the AND gate is
The output of AG ₄ has become 0. Also, switch
When SW ₄ is “OFF”, the output of inverter IN ₂ is “high”, so the gate of AND gate AG ₄ is opened and the set aperture value AVs is output from AND gate AG ₄ .
Data corresponding to is output.

Arithmetic circuit AL has AND gates AG ₀ , AG ₂ , AG ₄ ,
AG ₆ , distance signal output device DI, A-D converter
Based on the data from the AD and setting device SE ₈ , calculations are performed according to the above-mentioned formula to calculate the exposure control value, light emission amount, lighting contrast, and step difference. Data corresponding to the calculated exposure control value and the calculated lighting contrast or step difference are input to the display device DS, and the calculated values are displayed.

Data corresponding to the calculated or set aperture value from the arithmetic circuit AL is input to the aperture control device CA, and the aperture is controlled to the aperture value corresponding to the input data by the function of the well-known aperture control device CA. . In addition, data corresponding to the exposure time calculated or set from the arithmetic circuit AL is input to the shutter control device CT, and the data corresponding to the exposure time calculated or set from the arithmetic circuit AL is inputted to the shutter control device CT.
The CT function allows you to obtain an exposure time that corresponds to the input data. The light emission amount data calculated by the arithmetic circuit AL is converted into an analog signal by the D-A converter DA, and this analog signal is input to the light emission amount control circuit CF, which controls the flash light emitting device ST as described later. The amount of light emitted is controlled.

Further, when data is not output from the AND gates AG ₀ and AG ₂ , the arithmetic circuit AL performs calculations for normal natural light photography or flash photography to control exposure. Furthermore, at this time, since the output of the OR circuit OR ₀ is "low", the FET (FT ₀ ) is non-conductive and no signal is input to the control circuit CF. Control circuit CF
detects this as will be described later, and when the preparation for emitting light is completed, normal light emission and light emission amount control are performed.

FIG. 2 is a block diagram for explaining the operation of an arithmetic circuit AL that converts object brightness from the reflected light method from the A-D converter AD into object brightness BVa using the incident light method. . A-D converter
Data BVa' from AD is set in register 12. On the other hand, the data from the output circuit 10 that outputs fixed data k corresponding to the average reflectance of the object and the data from the register 12 are input to the adder circuit 14, and BVa=BVa'+k...(13) These calculations are performed to calculate object brightness data BVa using the incident light method. This calculated data is set in the register 18 shown in FIG. 3 and below.

Figure 3 shows the calculation circuit when exposure time TVs and lighting contrast Δ ₁ are set.
FIG. 2 is a block diagram for explaining the operation of AL.
The data BVa from the register 18 to which the data from the adder circuit 14 is set and the data TVs from the register 20 to which the data from the AND gate AG ₆ is set are input to the subtraction circuit 24, and the data corresponding to BVa-TVs is inputted to the subtraction circuit 24. is calculated. Then, this data and the data corresponding to the set lighting contrast Δ ₁ from the register 16 are input to the adder circuit 28, and the calculation of Δ ₁ + (BVa − TVs) = QVf (5-1) is performed. is performed, and the amount of light incident on the subject due to flash light emission is calculated.

On the other hand, the data corresponding to the set writing contrast Δ ₁ from register 16 is stored in the ROM.
Specify 26 addresses. Then, the ROM 26 outputs data corresponding to the set writing contrast Δ ₁ fixedly stored at the designated address, log ₂ (1+2 ^- 〓 ¹ ). That is, the ROM 26 has a writing contrast Δ ₁
It functions as a data converter that converts data corresponding to log ₂ (1 + 2 ^- 〓 ¹ ). Then, data QVf from the adder circuit 28 and data log ₂ (1+
2 ^- 〓 ¹ ) and film sensitivity SV from register 22
The data corresponding to the control aperture value AVx is input to the adder circuit 30, and the calculation AVx=QVf+SV+log ₂ (1+2 ^- 〓 ¹ )...(7) is performed to calculate the data corresponding to the control aperture value AVx, which is then sent to the aperture control device CA. and is input to the display device DS.

In addition, the data conversion ROM 32 uses the writing contrast Δ ₁ set from the register 16.
The data corresponding to Δ ₂ =log ₂ (1+2〓 ¹ )...(6-1) is converted into data corresponding to Δ 2 =log 2 (1+2〓 1 )...(6-1). As described above, this data corresponds to the difference in the number of stages, and this data is input to the display device DS.

The data corresponding to the amount of light QVf incident on the subject due to flash light emission from the adder circuit 28 and the data from the fixed data output circuit 38 that outputs fixed data corresponding to 5 are input to the adder circuit 40, where the calculation of QVf+5 is performed. Furthermore, this data is shifted by one bit to the lower bit by the shift circuit 42 and converted into data corresponding to (QVf+5)/2.

On the other hand, the data from the register 34 in which the data L from the distance signal output device DI is set is input to the data conversion ROM 36 and converted into data corresponding to log ₂ L. This data conversion ROM3
The data corresponding to log ₂ L from 6 and the data corresponding to (5+QVf)/2 from the shift circuit 42 are input to the adder circuit 44, and log ₂ (α・G)=(QVf+5)/2+log ₂ L
...(2-2) is performed, and data corresponding to the amount of light emitted by the flashlight emitting device ST is calculated. This calculated
Data corresponding to log ₂ (α・G) is sent to the D-A converter.
Input to DA.

Further, data corresponding to the set exposure time TVs is input to the shutter control device CT.

FIG. 4 is a block diagram illustrating the operation of the arithmetic circuit AL when lighting contrast is set in the aperture priority mode. Data from the register 46 in which data corresponding to the set aperture value AVs is set and data corresponding to the film sensitivity SV from the register 22 are input to a subtraction circuit 50 to calculate data corresponding to AVs-SV. On the other hand, data corresponding to log ₂ (1+2 ^- 〓 ¹ ) is output based on the data from the register 16 from the data conversion ROM 26, and the data from the data conversion ROM 26 and the data from the subtraction circuit 50 are subtracted. It is input to the circuit 52 and the calculation of QVf=AVs-SV-log ₂ (1+2 ^- 〓 ¹ )...(8) is performed. Therefore, data corresponding to the amount of light QVf incident on the subject due to flash light emission is calculated. The data corresponding to the calculated QVf is sent to the adder circuit 40 in FIG. 3, and similarly to FIG. 3, data corresponding to the light emission amount log ₂ (α·G) of the flash light emitting device ST is calculated.

On the other hand, the data corresponding to Δ ₁ from the register 16 and the data corresponding to BVa from the register 18 are input to the adder circuit 48, where the calculation of Δ ₁ +BVa is performed. The data from the addition circuit 48 and the data corresponding to QVf from the subtraction circuit 52 are input to the subtraction circuit 54, and the calculation of TVx=Δ ₁ +BVa−QVf (5-2) is performed. The data corresponding to the exposure time TVx calculated by this subtraction circuit 54 is displayed on the display device.
Input to DS and shutter control device CT.

Further, data corresponding to Δ ₁ from the register 16 is sent to the data conversion ROM 32 shown in FIG. 3, and data for the difference in the number of stages Δ ₂ is output to the display device DS.
Further, data corresponding to AVs from the register 46 is input to the aperture control device CA.

Figure 5 shows the calculation circuit when data corresponding to step number difference Δ ₂ is set in exposure time priority mode.
FIG. 3 is a block diagram for explaining the operation of AL. Data corresponding to BVa from the register 18 and data corresponding to TVs from the register 20 are input to the subtraction circuit 24. This subtraction circuit 24 calculates BVa-TVs. Furthermore, the data from the register 56 corresponding to the set difference in the number of stages Δ ₂ is input to the data conversion ROM 58, and from this ROM 58, Δ ₁ =log ₂ (2〓 ¹ −1) ……(6-2) Data corresponding to is output. Data corresponding to this lighting contrast _Δ1 is input to the display device DS and displayed. Furthermore, the data from the ROM 58 and the data from the subtraction circuit 24 are input to the addition circuit 28, where the calculation of QVf=BVa−TVs+log ₂ (2〓 ² −1) ……(9) is performed, and the data from the flash light emitted to the subject is calculated. The amount of incident light QVf is calculated. This data is input to the adder circuit 40 in FIG. 3, and data corresponding to the light emission amount log ₂ (α・G) of the flashlight emitting device ST is calculated using the same process as explained in FIG. 3 above. .

In the adder circuit 60, the BVa from the register 18
The data corresponding to SVa and the data corresponding to SV from the register 22 are input, and the calculation BVa+SV is performed. The data from the adder circuit 60 and the data corresponding to the difference in the number of stages Δ ₂ from the register 56 are input to the adder circuit 62 where the calculation of BVa + SV + Δ ₂ is performed. The data corresponding to the aperture value AVx is input to the subtraction circuit 64, and the following calculation is performed: AVx=(BVa-TVs)+Δ ₂ +SV (10), and the data corresponding to the aperture value AVx is calculated. This data is for the aperture control device.
Input to CA and display device DS. Furthermore, data corresponding to the set exposure time TVs from the register 20 is input to the shutter control device CT.

FIG. 6 is a block diagram for explaining the operation of the arithmetic circuit AL when the step number difference _Δ2 is set in the aperture priority mode. First, the adder circuit 60 receives data corresponding to BVa from the register 18,
Data corresponding to the SV from the register 22 is input and the calculation of BVa+SV is performed. The calculated data and the data corresponding to the difference in the number of stages Δ ₂ from the register 56 are input to the adder circuit 62 and the calculation of BVa+SV+Δ ₂ is performed. Next, this calculated data and the data corresponding to the set aperture value AVs from the register 46 are input to the subtraction circuit 66, and the calculation of TVx=Δ ₂ +BVa−(AVs−SV) ……(6-3) is performed. data corresponding to the exposure time TVx is calculated. Data corresponding to this TVx is input to the display device DS and the shutter control device CT.

Furthermore, the data corresponding to the calculated TVx and the data corresponding to BVa from the register 18 are input to the subtraction circuit 24, where the calculation of BVa-TVx is performed. In addition, the data corresponding to the stage number difference Δ ₂ from the register 56 is stored in the data conversion ROM.
The data corresponding to Δ ₁ =log ₂ (2〓 ² -1) . . . (6-2) is output from the ROM 58.
Data corresponding to the writing contrast _Δ1 from this ROM 58 is input to the display device DS.

Furthermore, the data from the ROM 58 and the subtraction circuit 2
The data from 4 is input to the adder circuit 28, where the calculation QVf=(BVa−TVx)+log ₂ (2〓 ² −1) ……(9-1) is performed, and the amount of light incident on the subject due to flash light emission is calculated. Data corresponding to QVf is calculated, and thereafter, data corresponding to the light emission amount log ₂ (α·G) of the flashlight emitting device ST is calculated in a process similar to that shown in FIG.

FIG. 7 is a block diagram showing a second embodiment of the invention. Only the points different from FIG. 1 will be explained.
In this embodiment, the amount of light QVf incident on the subject by flashlight emission can be manually set in the setting device _SE10 . When switch SW ₆ is “ON” and a light emission ready signal is input from the signal output circuit SO of the flash light emitting device ST, the AND gate AG ₈ outputs the setting device.
Data from SE ₁₀ is output and input to the arithmetic circuit AL. In addition, when data is being output from the AND gate _AG8 , the output of the OR circuit _OR0 becomes "high", the FET ( _FT0 ) becomes conductive, and the amount of flash light emitted from the DA converter _DA0 increases. An analog signal corresponding to is input to the light emission amount control circuit CF.

Based on various input data, the arithmetic circuit AL
Data corresponding to lighting contrast Δ ₁ , data corresponding to step number difference Δ ₂ , flash light emission amount log ₂
Data corresponding to (α·G) and data corresponding to the exposure time TVx or the aperture value AVx are calculated.
Further, as in FIG. 1, when no data is output from the AND gate AG ₈ , the arithmetic circuit AL performs well-known arithmetic operations for normal natural light photography or flash photography.

Figure 8 shows the amount of light incident on the subject due to flash light emission.
FIG. 3 is a block diagram for explaining the operation of the arithmetic circuit AL when QVf is set and the exposure time priority mode is set. First, data corresponding to QVf from the register 68 is calculated as data corresponding to the light emission amount log ₂ (α·G) of the flashlight emitting device ST in the same manner as in FIG. BVa from the register 18 is sent to the subtraction circuit 24.
The data corresponding to TVs and the data corresponding to TVs from the register 20 are input, and the calculation of BVa-TVs is performed. This calculated data and
The data corresponding to QVf from the register 68 is input to the subtraction circuit 70, where the calculation Δ ₁ =QVf−(BVa−TVs) (5) is performed, and the data corresponding to the lighting contrast Δ ₁ is calculated. Ru. This calculated data is input to the display device DS. Also,
This data is input to the data conversion ROM 32 and converted into data corresponding to the step number difference Δ ₂ expressed as Δ ₂ =log ₂ (1+2〓 ¹ )...(6-1), and this data is sent to the display device DS. Sent.

The data corresponding to the writing contrast Δ ₁ from the subtraction circuit 70 is further used for data conversion.
The data is input to the ROM 26 and converted into data corresponding to log ₂ (1+2 ^- 〓 ¹ ). This data, the data from the subtraction circuit 24, and the data from the register 22 are input to the addition circuit 30, and the calculation of AVx=QVf+SV+log ₂ (1+2 ^- 〓 ¹ )...(7) is performed, and the aperture value AVx is Corresponding data is calculated. This data is input to the display device DS and the aperture control device CA. Also register 2
Data corresponding to TVs starting from 0 is input to the shutter controller CT.

Figure 9 shows the arithmetic circuit in aperture priority mode when the amount of light incident on the subject is set.
FIG. 2 is a block diagram for explaining the operation of AL.
The data corresponding to BVa from the register 18 and the data corresponding to SV from the register 22 are input to the adder circuit 60, and the calculation of BVa+SV is performed. The calculated data and the data corresponding to the set aperture value AVs from the register 46 are input to the subtraction circuit 74, and data corresponding to the exposure time TVa determined by only the stationary light TVa=BVa+SV-AVs is calculated.

On the other hand, the data from the register 68 is sent to the adder circuit 72.
Data corresponding to QVf and SV from register 22
The data corresponding to QVf+SV=AVf...(3) is calculated, and the data corresponding to the aperture value AVf determined only by the amount of incident light QVf due to the flash is calculated. This calculated data and the data from the register 46 are input to the subtraction circuit 76, and the calculation of AVs-AVf=Δ ₃ (11) is performed. The data corresponding to Δ ₃ calculated by the subtraction circuit 76 is stored in the data conversion ROM 78.
This ROM 78 outputs data corresponding to -log ₂ (1-2 ^- 〓 ³ ). Then, this data and the data corresponding to TVa calculated by the subtraction circuit 74 are input to the addition circuit 80, and the calculation of TVa+{-log ₂ (1-2 ^- 〓 ³ )}=TVx...(12) is performed. Data corresponding to the exposure time TVx is calculated and input to the display device DS and shutter control device CT.

Data corresponding to the exposure time TVx from the adder circuit 80 is input to the subtracter circuit 24, and the data corresponding to the exposure time TVx is inputted to the subtracter circuit 24,
Similarly, the data from BVa-TVx is inputted, and the calculated data and the data corresponding to QVf from the register 68 are inputted to the subtraction circuit 70, where Δ ₁ =QVf-(BVa-TVx ) ...(5) is performed, and data corresponding to the lighting contrast Δ ₁ is calculated and input to the display device DS. In addition, the data corresponding to the calculated lighting contrast Δ ₁ is used for data conversion.
Data that is input to the ROM 32 and corresponds to Δ ₂ =log _{2 (} 1+2〓 ¹ ) .

The data corresponding to the amount of light QVf incident on the subject due to the set flash light from the register 68 is input to the adder circuit 40 shown in _FIG . α・G) is calculated. Also, register 4
The data corresponding to the set aperture value AVs from 6 is input to the aperture control device CA.

FIG. 10 shows a specific circuit example of a flash light emitting device ST for carrying out the present invention. The configuration and operation will be explained below. When power switch SW ₈ is closed, switch SW ₁₀ linked thereto is also closed. Then, the booster circuit DD operates and the diode
The main capacitor _C4 is charged via _D4 .
When the charging voltage of the main capacitor C ₄ reaches a predetermined value, the neon tube NE lights up and the potential at the connection point of the resistors R ₁₀ and R ₁₂ rises, enabling the transistors BT ₀ and BT ₂ and the thyristor SC ₀ to conduct. BT ₄ ,
BT ₆ becomes conductive, the potential at the connection point between resistors R ₆ and R ₈ rises, and a signal that light emission preparation is completed is output to the camera side via terminals J ₁₀ and J ₁₁ .

Light emission amount from the camera side via terminals J ₂₁ and J ₂₀
When an analog signal corresponding to log ₂ (α·G) is input, this voltage is compared with the output voltage of the constant voltage source CE. Here, the output level of constant voltage source CE is
It is set lower than the lowest value of the input signal from the camera side, so the output of comparator OA ₀ is always “low” when a signal is input from the camera side.
When no signal is input, the inverting terminal is at ground potential, so the output of comparator OA ₀ becomes "high".

When a signal is input, the output of comparator OA ₀ becomes “low”, and the p-channel FET,
FT ₂ , ET ₄ , and FT ₈ become conductive. Further, when no signal is input and the output of the comparator OA ₀ is "high", the n-channel FETs, FT ₁ and FT ₆ are conductive.

Next, with a signal corresponding to the amount of light emitted being input from the camera side, when the X contact SX on the camera side is closed, transistors BT ₀ and BT ₂ become conductive, thyristor SC ₀ becomes conductive, and the trigger is activated. Circuit TR works. This allows xenon tube XE, thyristor
SC ₂ becomes conductive and starts emitting light. This xenon tube
The output current of the photo transistor PT ₁ , which is installed in a position to directly receive the light emitted from the XE, is FET, FT ₄
The output current flows into resistor R ₀ through R 0 and is converted to voltage. Then, due to the light emission of the xenon tube XE, the voltage across the resistor R ₀ changes, that is, the xenon tube
Only the voltage corresponding to the light emission of XE is output from the high-pass filter consisting of capacitor _{C0 and} resistor _R2 . The output of this high-pass filter is
It is converted into a current by a voltage-current conversion circuit composed of an operational amplifier OA ₂ , a transistor BT ₁₄ , and a resistor R ₄ , and this current is converted into a current by a transistor BT ₁₂ , a FET,
Diode D ₀ , D ₂ , capacitor C ₂ through FT ₈
Flows into a known logarithmic compression and integration circuit configured with . At this time, transistor BT ₀ is conductive, and transistors BT ₈ and BT ₁₀ are non-conductive. Furthermore, even if the charging voltage of _the main capacitor decreases due to the light emission of the xenon tube XE and the neon tube NE becomes non-conductive, the time required for the xenon tube The transistors BT ₀ and BT ₄ remain conductive.

The charging voltage of capacitor C ₂ and the analog signal of log ₂ (α・G) corresponding to the amount of flash light emitted from FET and FT ₂ are compared by comparator OA ₄ , and when the two match, this output becomes “high”. Inversely, the light emission stop circuit CS operates and the light emission of the xenon tube XE is stopped.

When the signal corresponding to the flash light emission amount log ₂ (α・G) is not input from the camera side, FET, FT ₁ ,
When FT ₆ is conducting, the logarithmic compression integrator circuit consisting of diodes D ₀ , D ₂ and capacitor C ₂ has:
The output current from the photo transistor PT ₂ for reflected light flows in, and the inverting input terminal of the comparator OA ₄ receives an analog signal from a variable voltage source that outputs a voltage corresponding to the film sensitivity and photographing aperture of the film used. is input. Therefore, in this case, light amount control is performed in the same way as in a normal auto strobe.

Although the embodiment of the present invention is shown only as a block diagram, those skilled in the art can easily create a program for, for example, a microcomputer according to this block diagram and implement the program using the microcomputer.

Also, although only the cases of aperture priority mode and exposure time priority mode are explained, in the case of manual setting mode, for example, the same calculation as in exposure time priority mode is performed, and the calculated aperture value and the set aperture value are What is necessary is to display the error between the two. Further, in the case of a program shutter in which the combination of aperture value and exposure time is determined based on the brightness of stationary light, calculations similar to those in the exposure time priority mode may be performed, for example.

In addition, lighting contrast, step difference,
A light emission amount setting device is provided on the flashlight emitting device side so that an analog signal is output, and the A-
It may be D-converted and input to the arithmetic circuit.

Effects As described above, according to the present invention, it is possible to perform flash photography that takes both steady light and flash light into consideration, and furthermore, since the amount of flash light emission is determined based on distance information, the reflection of the subject can be This enables flash photography that is not affected by the rate.

[Brief explanation of drawings]

FIG. 1 shows a first embodiment of the invention. Second
The figure is a block diagram to explain the operation of the arithmetic circuit AL that converts the output of the reflected light type photometry circuit into the incident light type photometry value. Figure 3 shows when lighting contrast is set in exposure time priority mode. A block diagram to explain the operation of the arithmetic circuit AL,
Figure 4 is a block diagram to explain the operation of the calculation circuit AL when lighting contrast is set in aperture priority mode, and Figure 5 is a block diagram for explaining the operation when lighting contrast is set in exposure time priority mode. A block diagram to explain the operation of circuit AL,
FIG. 6 is a block diagram for explaining the operation of the arithmetic circuit AL when the step number difference is set in the aperture priority mode. FIG. 7 is a block diagram showing a second embodiment of the present invention, and FIG. 8 is for explaining the operation of the arithmetic circuit AL when the amount of light incident on the subject by flashlight emission is set in the exposure time priority mode. 9 is a block diagram for explaining the operation of the arithmetic circuit AL when the amount of light incident on the subject by flashlight emission is set in aperture priority mode, and FIG. 10 is a block diagram for implementing the present invention. This is a specific example of a circuit of a flashlight emitting device suitable for. SE ₀ ; Lighting/contrast setting device,
SE ₂ ; Step difference setting device, DI; Distance signal output device,
LM ₀ : Ambient light metering circuit, SE ₄ : Aperture value setting device, SE ₆ : Exposure time setting device, SE ₈ : Film sensitivity setting device, AL: Arithmetic circuit, CA: Aperture control device, CT: Shutter control device, DS; display device,
ST: Flash light emitting device, CF: Flash light emission amount control circuit,
SE ₁₀ ; Device for setting the amount of light incident on the subject using flash light emission.

Claims (1)

[Claims] 1. A photometric circuit that measures ambient light, an output device that outputs a signal corresponding to an exposure time, and a generator that generates a distance signal to a subject, and that contributes to ambient light photography. a setting device for setting a signal corresponding to a lighting contrast defined as the ratio between the amount and the contribution of the flash to the photographing;
A calculation circuit that calculates a signal corresponding to the amount of light emitted from the flash based on signals from the lighting/contrast setting device, the photometry circuit, the output device, and the light emitting device, and a signal corresponding to the amount of light emission from the calculation circuit. 1. An exposure control device for flash photography, comprising: a control circuit that controls the amount of flash light emitted based on. 2 The above photometric circuit is a reflected light type photometric circuit,
2. The exposure control device for flash photography according to claim 1, wherein said arithmetic circuit converts the signal from said photometric circuit into a value for an incident light type. 3 The control circuit for controlling the amount of flash light emission includes a light receiving element that receives the flash light in the form of incident light, an integrating circuit that integrates the output current of this light receiving element, and a signal from the integrating circuit and the flash light from the arithmetic circuit. The exposure for flash photography according to claim 1, characterized in that it is provided with a comparison circuit that compares a signal corresponding to the amount of light emitted by the light emitting device, and a stop circuit that stops the light emission based on the signal from the comparison circuit. Control device. 4 The output device further outputs a signal corresponding to the film sensitivity, and the arithmetic circuit receives a signal corresponding to the exposure time from the output device, a signal corresponding to lighting contrast from the setting device, and the photometry circuit. A signal corresponding to the amount of light from the flash incident on the subject is calculated based on the signal from the flash light source, and a signal corresponding to the amount of light from the flash incident on the subject is calculated, and a signal corresponding to the amount of light from the flash incident on the subject is calculated, as well as a distance signal from the above generation circuit. In addition to calculating a signal corresponding to the amount of light emitted by the subject, a signal corresponding to the amount of light from the flash incident on the subject, a signal corresponding to the film sensitivity from the output device, and a signal corresponding to the lighting contrast are also calculated. An exposure control device for flash photography according to any one of claims 1 to 3, characterized in that a signal corresponding to a control aperture value is calculated. 5 Equipped with a photometry circuit that measures ambient light, an output device that outputs a signal corresponding to the aperture value and a signal that corresponds to film sensitivity, and a generator that generates a distance signal to the subject, and that a setting device for setting a signal corresponding to a lighting contrast defined as a ratio between a contribution amount and a contribution amount to flash photography; An arithmetic circuit that calculates a signal corresponding to the amount of flash light for appropriate exposure based on the signal and a signal corresponding to the exposure time, and a calculation circuit that calculates the amount of flash light emitted based on the signal corresponding to the amount of light emitted from this arithmetic circuit. 1. An exposure control device for flash photography, comprising a control circuit that controls the shutter based on a signal corresponding to an exposure time. 6 The above photometric circuit is a reflected light type photometric circuit,
6. The exposure control device for flash photography according to claim 5, wherein said arithmetic circuit converts the signal from said photometric circuit into a value for an incident light type. 7 The control circuit that controls the amount of flash light emission includes a light receiving element that receives the flash light in the form of incident light, an integrating circuit that integrates the output current of this light receiving element, a signal from this integrating circuit, and a signal from the arithmetic circuit. Flash photography according to claim 5, characterized in that it comprises a comparison circuit that compares a signal corresponding to the amount of light emitted by the flash, and a stop circuit that stops the light emission based on the signal from the comparison circuit. Exposure control device. 8. Equipped with a photometry circuit that measures ambient light, an output device that outputs a signal corresponding to the exposure time, and a generator that generates a distance signal to the subject, and that determines the amount of contribution of ambient light to photography and the amount of flash added to ambient light. a setting device for setting a step difference defined as a ratio of the contribution amount to the shooting including the step difference setting device;
an arithmetic circuit that calculates a signal corresponding to the amount of light emitted by the flash based on the signals from the photometric circuit, the output device, and the generator; 1. An exposure control device for flash photography, comprising a control circuit for controlling the exposure. 9 The above photometric circuit is a reflected light type photometric circuit,
9. The exposure control device for flash photography according to claim 8, wherein said arithmetic circuit converts the signal from said photometric circuit into a value for an incident light type. 10 The control circuit that controls the amount of flash light emission includes a light receiving element that receives the flash light in the form of incident light, an integrating circuit that integrates the output current of this light receiving element, and a signal from the integrating circuit and the flash light from the arithmetic circuit. Exposure for flash photography according to claim 8, characterized in that it is provided with a comparison circuit that compares a signal corresponding to the amount of light emission with a signal corresponding to the amount of light emission, and a stop circuit that stops light emission based on the signal from the comparison circuit. Control device. 11 The output device further outputs a signal corresponding to the film sensitivity, and the arithmetic circuit receives a signal corresponding to the exposure time from the output device, a signal corresponding to the step number difference from the setting device, and a signal from the photometry circuit. A signal corresponding to the amount of light from the flash incident on the subject is calculated based on the signal of In addition to calculating a signal corresponding to the amount of light emitted,
A signal corresponding to the control aperture value is calculated based on a signal corresponding to the exposure time from the output device, a signal corresponding to the film sensitivity, a signal from the photometry circuit, and a step difference signal from the setting device. Claims 8 to 10 are characterized in that:
3. Exposure control device for flash photography according to any one of paragraphs. 12 Equipped with a photometry circuit that measures ambient light, an output device that outputs a signal corresponding to the aperture value and a signal that corresponds to film sensitivity, and a generator that generates a distance signal to the subject, and that a setting device for setting a step difference defined as a ratio between a contribution amount and a contribution amount for shooting with flash light added to steady light; the step difference setting device; the photometry circuit;
an arithmetic circuit that calculates a signal corresponding to an exposure time for a proper exposure based on signals from the output device and the generator, and a signal corresponding to the amount of light emitted from the flash; 1. An exposure control device for flash photography, comprising a control circuit that controls the amount of flash light emitted based on a signal and controls a shutter based on a signal corresponding to an exposure time. 13. The flash according to claim 12, wherein the photometric circuit is a reflected light type photometric circuit, and the arithmetic circuit converts the signal from the photometric circuit to a value for an incident light type. Exposure control device for photography. 14 The control circuit that controls the amount of flash light emission includes a light receiving element that receives the flash light in the form of incident light, an integrating circuit that integrates the output current of this light receiving element, and a signal from the integrating circuit and the flash light from the arithmetic circuit. Claim 12, comprising: a comparison circuit that compares the amount of light emitted with a signal corresponding to the amount of light emitted; and a stop circuit that stops the light emission based on the signal from the comparison circuit.
Exposure control device for flash photography as described in .