JPS642927B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photometric device for flash photography. In conventional flash photography photometry devices and photometry methods, once an exposure time is set, photometry is continued for the set exposure time, and an appropriate aperture value is obtained using the integrated light amount during this time. Therefore, in such a device,
When the exposure time is set to a long time, it is necessary to hold the photometering device in a fixed position during the exposure time, and there is also the drawback that photometry takes time. In addition, with the conventional photometer for flash photography mentioned above, when the set exposure time is changed, the amount of flash light is switched, or the ambient light changes, the flash must be fired again to obtain the appropriate aperture value. It was necessary to perform photometry. Furthermore, Tokko Sho (No. 47-2756), Tokko Sho (No. 47-4088), and Tokko Sho (No. 47-4089) used a high-pass filter to convert the photometric output during flash emission into the steady light component and the flash light component. A device has been proposed that controls the amount of flash light emitted by dividing it into components and taking into account the effects of stationary light, but it is impossible to obtain data on the aperture value described above with this device. The present invention proposes a device that obtains an appropriate aperture value without continuing photometry during a set exposure time and also takes into account ambient light. That is, the present invention provides a light metering device for flash photography that determines an appropriate aperture value for the sum of the amount of steady light and the amount of flash light received within a set exposure time. a first means for obtaining a first signal by integrating the photometric output for a predetermined integration time including a predetermined integration time; a second means for obtaining a second signal indicating the steady light intensity based on the photometric output when the flash is not emitting light; a third means for obtaining a third signal that includes information only about the amount of flash received light integrated within the integration time based on time information, the first signal, and the second signal; and information about the set exposure time. Fourth
a fourth means for outputting a signal; a fifth means for outputting a fifth signal including information on film sensitivity; and a fifth means for calculating an appropriate aperture value based on the second, third, fourth and fifth signals. This is a newly created photometric device for flash photography characterized by having six means. First, the principle of this invention will be explained with reference to FIG. It is assumed that the exposure time (TVs) and film sensitivity (SV) have been set in advance, and as shown in Figure 1, the photometry time when the flashlight is fired is t ₁ (TV ₁ in the ) Let the photometry time when there is only steady light be t ₂ (TV ₂ in abecs value),
The photometric output when the flash Ps(t) is fired is QVfa,
Let QVa be the photometric output when there is only steady light Pa.
Also, when the flash Ps(t) is emitted, the steady light Pa
Let QVf be the photometric output when P is set to 0, that is, the photometric output based only on light Ps(t) as the amount of flash light. Furthermore, as the instantaneous light intensity, the apex value of the light intensity determined only by the steady light is defined as BVa. Then, the photometric output QVfa and QVf have the following relationship; 2 ^QVfa = ∫ ^t1 ₀ {Ps (t) + Pa} dt = 2 ^QVf + 2 ^BVa-TV1 ...(a) 2 ^QVa = ∫ ^t2 ₀ Pdt = 2 ^BVa-TV2 ...(b) QVa=BVa-TV ₂ ...(b') By the way, the difference in the effects of flashing light and steady light on the subject is expressed in the apex system; that is, the lighting contrast is exposure time
If TVs, it is defined as Δ ₂ ≡QVf−(BVa−TVs) ……(c). Therefore, the lighting contrast Δ ₂ is calculated from the photometric values QVfa and QVa to QVf, (BVa−
TVs) and find the difference between these two calculated values. Therefore, if we define Δ ₁ as Δ ₁ ≡QVfa− (BVa−TV ₁ ) ...(d) and eliminate BV−TV from equation (a), we get 2 ^QVf = 2 ^QVfa (1−2 ^- 〓 ¹ )...(e), and by taking the logarithm of both sides, we obtain the relationship QVf=QVfa+log ₂ (1-2 ^- 〓 ¹ )...(f). Note that BVa−TV ₁ is determined from BVa−TV ₁ =QVa+TV ₂ −TV ₁ (g). Also, if the exposure time is TV, it can be found as BVa−TVs=QVa+TV ₂ −TVs ……(h). Therefore, the lighting contrast Δ ₂ is determined from the above equation (c) based on the results of equations (f) and (h). Here, when calculating equation (f), BVa−TV ₁ is eliminated, but QVfa is eliminated, and QVf=(BVa−TV ₁ )+log ₂ (2〓 ¹ −1)
...(f') and calculate log ₂ (2〓 ¹ -1) for Δ ₁ . Furthermore, even if it is defined as (BVa−TV ₁ )−QVfa≡Δ ₁₁ ……(d′), QVf can be found using the same procedure. Furthermore, in order to obtain QVf, it is not necessarily necessary to obtain it by the above-mentioned calculation, but if a high-pass filter is connected to the photometric output during flash firing as is well known, it is possible to calculate QVf from the high-pass filter. The steady light component is cut out and only the flash component is output, and QVf can be found by integrating this output. Next, the principle of determining the appropriate aperture value AVx when the exposure time TVs is set will be explained. In general, the conditions for proper exposure during flash emission are expressed as follows: 2 ^SV. (2 ^QVf + 2 ^BVa-TV ) = 2 ^AV (i ₁ ). Furthermore, when only a flash is irradiated,
The conditional expressions for proper exposure when only steady light is irradiated are as follows: 2 ^QVf+SV = 2 ^AVf ... (i ₂ ) 2 ^{BVa + SV-TV} = 2 ^AVa ... (i ₃ ) . Here, AVf is the appropriate aperture value when there is only flash light, and AVa is the appropriate aperture value when there is only steady light. If we replace TV in equations (i ₁ ) to (i ₃ ) with the set exposure time TVs and transform equation (i ₁ ), we get 2 ^AVx = 2 ^AVf + 2 ^AVa ... (j). Here, AVf is the value obtained by adding the film sensitivity SV to QVf determined by equation (f), as seen from equation (i ₂ ), and AVa is calculated from equation (i ₃ ) as AVa=QVa+TV ₂ +SV−TVs It can be found by Here, if AVf−AVa≡Δ ₂₀ is defined, this Δ ₂₀ matches the lighting contrast Δ ₂ defined by equation (c). Therefore, AVf−AVa=Δ ₂ ...(k), and by eliminating AVf from equations (i) and (k) and taking the logarithm of both sides, AVx=AVa+log ₂ (1+2〓 ² ...(l ), the appropriate aperture value AVx is the appropriate aperture value AVa for steady light only, plus the lighting contrast Δ ₂
It can be solved by adding log ₂ (1+2〓 ² ) based on . Note that in order to obtain the appropriate aperture value AVx, it is not necessarily necessary to obtain AVf, and it is also possible to obtain it as shown below. First, the photometric amount QVfa at the time of flash emission is taken as one flash emission amount, and QVfa + SV = AVfa ... (m) is calculated, and the time from the end of the flash emission until the set exposure time elapses is TV _s1 , AV _a1 = QVa + TV ₂ + SV - TV _s1 ... (n) is obtained, and from the relationship 2 ^AVx = 2 ^AVfa + 2 ^AVa1 ... (j'), it is also possible to obtain AVx using the same procedure as described above. Here, TV _s1 is found as follows. First, there is the following relationship between TV _s1 , TVs, and TV ₁ ; 2 ^-TVs1 = 2 ^-TVs -2 ^-TV1 ... (α) Then, Δ ₄ ≡TV ₁ - TVs (>0) ... By defining (β), eliminating TV ₁ from equation (α), rearranging it, and taking the logarithm of both sides, we find TV _s1 = TVs−log ₂ (1−2 ⁻ 〓 ⁴ ) ……(γ). Also, when the set exposure time is changed from TVs to TVs′, change BVa−TVs found by equation (h) to BVa−TVs′=QVa+TV ₂ −TVs′ ……(h′) and calculate Δ ₂ ′=QVf−(BVa−TVs′) …(c′) The lighting contrast can be obtained, and the appropriate aperture value AVx′ can be obtained by finding AVa′=QVa+TV ₂ +SV−TVs′, AVx′= It can be found from AVa′+log ₂ (1+2〓 ² ′) ...(l′). Further, when switching the amount of flash light emission, if the switching amount is Δf, then the amount of flash light emission is QVf′=QVf−Δf (p). Therefore, the lighting contrast Δ ₂ ″ can be found from Δ ₂ ″=QVf′−(BVa−TVs) ……(c″). Furthermore, the appropriate aperture value is AVx″=AVa+log ₂ (1+2〓 ² ″… ...(l″). In the photographic screen, there are parts that are illuminated by flash and constant light, and parts that are not illuminated by flash and are illuminated only by constant light. At this time, within the exposure time TVs, , the total amount of light received from the parts illuminated by flash and steady light 2 ^QVfa ′ is expressed as 2 ^QVf + 2 ^BVa-TVs = 2 ^QVfa ′ ... (q). Also, the contrast between the above two types of parts is , QVfa′−(BVa−TVs) ...(r).By the way, as can be seen from equation (i ₁ ), equation (q) can be transformed as 2 ^AVf + 2 ^AVa = 2 ^AVx ...(j) Therefore, (r) becomes AVx - AVa ... (r'), and this value corresponds to the log ₂ (1 + 2 〓 ² ) mentioned above. Also, the flash light for the subject illuminated by flash light and steady light 2 ^QVf + 2 ^BVa-TVs = 2 ^QVfa ′ ...(q) The ratio of the contribution amount is the received amount when flash light and steady light are irradiated, and QVfa′ when only steady light is irradiated. This is the difference from ^BVa-TVs , which _is determined by the amount of light received when
2〓 ² ). Next, when the aperture value AVs is set,
The principle of determining the appropriate exposure time TVx will be explained. In this case, the formula (i ₁ ) becomes 2 ^SV・(2 ^QVf + 2 ^BVa-TVx )=2 ^AVs (i ₁₀ ). By the way, QVf is (f) using the same procedure as above.
Find it from the formula, and then find QVf + SV = AVf, find the appropriate exposure time TVa = BVa + SV - AVs when only steady light is irradiated, and define Δ ₃ ≡ AVs - AVf ... (s) Then, by eliminating AVf from equation (i ₁₀ ) and rearranging by taking the logarithm of both sides, TVx=TVa−log ₂ (1−2 ⁻ 〓 ³ ) ……(u) is obtained. Here, when AVs-AVf<α (α>0), the exposure time becomes shorter than the shortest seconds, so it is necessary to display overexposure. Further, the lighting contrast in this case can be defined as Δ ₂₁ ≡QVf−(BVa−TVx), and this value can be immediately determined from the value determined in the process of calculating TVx. Note that, in the same way as when setting the TVs described above, the values when changing the AVs and the amount of flash light emission can be calculated. Furthermore, the contrast between the part irradiated with flash light and the part not irradiated with flash light and the ratio of the amount of contribution of flash light and steady light are also determined by log ₂ (1+2〓 ²¹ ). Note that TVx can also be determined as follows. First, when AVfa is found according to equation (m), equation (i ₁₀ ) becomes 2 ^AVfa + 2 ^BAa+SV-TVx1 = 2 ^AVs . Here, 2 ^-TVx1 corresponds to the time from the end of the flash light emission to the end of the exposure time determined by TVx. Therefore, it is sufficient to first find TV _x1 based on the formula (i ₁₁ ), and then find TVx from TV _x1 . First, define Δ ₅ ≡ AVs − AVfa ... (s′), eliminate AVs from equations (i ₁₁ ) and (s′), and take the logarithm of both sides, TV _x1 = BVa + SV −AVfa −log ₂ (2〓 ⁵ −1) …(u′) is found. On the other hand, 2 ^{- TVx} = 2 ^{- TVx1} + 2 ^{- TV1} ... (α') holds between TV _x1 , TV ₁ , and TVx. Therefore, we define Δ ₄ ′≡TV ₁ −TV _x1 ……(β′), eliminate TV ₁ from equation (α′), rearrange it, and take the logarithm of both sides, TVx=TV _x1 −log ₂ (1+2 ^- 〓 ⁴ ′) …(u″) is found. According to the principle explained above, the photometric value QVfa,
From QVa, QVf, Δ ₂ , AVx, log ₂ (1+2〓 ₂ ),
It would be sufficient to find TVx, Δ ₂₁ , log ₂ (1+2〓 ²¹ ), but log ₂ (1−2 ^- 〓 ¹ ), log ₂ (1+2〓 ² ), log ₂
(1
−2 ^- 〓 ³ ) log ₂ (1 + 2〓 ²¹ ) can be realized as follows. Normally, the accuracy of photometric values and the accuracy of the required values are at most 0.1 EV units. Therefore, log ₂ (1-2 ^- 〓) and log ₂ for each value of Δ
(1+2〓) is calculated at the time of manufacturing, and the circuit device is calculated as log ₂ (1-2 ^- 〓) or log ₂ (1+2〓) corresponding to Δ.
A decoder or ROM (read-only memory) that outputs the value of can be used. Alternatively, if it is realized using a microcomputer, it is possible to determine in which region Δ is located and
This can also be achieved by outputting data corresponding to the area to which it belongs. Next, let Δa represent the value corresponding to Δ ₁ and Δ ₃ , and calculate log(1−2 ^- 〓 ^a ) for this Δa.
The values obtained by multiplying by 10 are shown in Table 1.

【table】

[Table] Note that the subscript H in the above table represents a hexadecimal number. Also, log _{2 ( 1}
+2〓 ^b ) determines the magnitude of AVa and AVf, and AVa≦
When AVf, AVa − AVf = Δb ₁ , and when AVa > AVf, AVf − AVa = Δb _2. From these relationships, calculate log ₂ (1 + 2〓 ^b ) for Δb ₁ and Δb ₂ according to Table 2. I ask for it.

[10Δ ₁ = 10 {QVfa−(BVa−TV ₁ )}]

Set to register #2R. Note that the photometric output is determined by the current i of the constant current source (Ic) and the resistance (R ₄ ) when the flash is emitted and when it is not.
is shifted by the potential generated by . Therefore, the difference between the apex value TV ₁ for the photometry time during flash irradiation and the apex value TV ₂ for the photometry time only in steady state is larger by a certain value than the difference in apex value for the actual time. Moreover, when Δ ₁ =0, that is, [BVa−TV ₁ =QVfa], [2QVfa=2BVa−TV ₁ =2QVf+2BVa−
TV ₁ ], and [2QVf=0]. Therefore, the flash from the flashlight emitter does not contribute to photographing. Therefore, if the zero flag is determined in step [ZF=1], the terminal of I/O port 406 (p ₃ )
is set to 1, and the display device 300 displays this fact. Thereafter, [BVa + SV - TVg = AVx] is calculated, the process moves to the 〓〓 step, the appropriate aperture value is displayed by the commands below that step, and the process returns to the start. When [10・Δ ₁ ≠ 0], find [log ₂ (1-2 ^- 〓 ¹ )] according to Table 1. First, 10・Δ ₁ is 01H
Between ~0BH, 10・Δ For every difference in ₁ , [−10・
Since the values of log ₂ (1-2 ^- 〓 ¹ )] are different, the value of register #2R is determined by subtracting 1 from the contents of the register. That is, every time 1 is subtracted from the contents of register #2R in the step, 1 is added to register #7R, and when the contents of register #2R becomes ^00H , the constant K ₂ is transferred to register #6R.
, and in the 〓〓 step, transfer the contents of the 16-bit register #6PR, that is, one of 27H to 09H in Table 1 stored at the ROM24 address specified by Δ ₁ + K ₂ , to the register #5R. Set it and jump to the step command. The contents of register #5R are [−10・
log ₂ (1-2 ^- 〓 ¹ )]. When _Δ1 is ^0CH or more, first go to register #5R.
Set 08H, determine whether the contents of register #2R are smaller than 02H, and if smaller, set [10・Δ ₁
= 0 ^C H ~ 0 ^C H] becomes [-10・log ₂ (1 + 2 ^- 〓 ¹ ) =
08H〓 Jump to the command of 〓〓. Similarly, the operation of subtracting 1 from the contents of register #5R and determining the contents of register #2R is repeated, and at the time of the 〓〓 step instruction, the contents of register #5R are [-10・log ₂ (1− 2 ^- 〓 ¹ )]. Next, in the steps 〓〓～〓〓, [QVfa+log ₂ (1-
2 ^- 〓 ¹ )], [QVf+SV=AVf], [BVa+SV−TV=
AVa] and set [10·(AVf+K ₁ )] to register #4R and [10·(AVa+K ₁ )] to register #3R. Next, in the 〓〓 step, determine the magnitude of #3R and #4R, and if [(#3R) <(#4R)], then in the 〓〓 step, subtract the contents of register #3R from the contents of register #4R. Calculate the difference between the effects of flash light and steady light [10・Δ ₂ ] by calculation, and calculate [(#3R) +
27H−(#4R)] and register #1R, respectively.
Set to #2R. Here, adding 27H is obvious from Table 2, when [AVa - AVf3.9], [log ₂ (1 + 2〓 ² )] becomes 0, and [AVa
-AVf0]. Also, when [(#3R) (#4R)], Δ ₂ becomes negative, so the terminal (p ₄ ) is set to "high" and this is indicated on the display, and [(#3R) - ( #4R)] and [(#4R)+27H-(#3R)] and set them in registers #1R and #2R, respectively. Next, 00H is set in register #5R, and the contents of register #5R are incremented by 1 while determining which area the contents of register #2R belong to according to Table 2. At the time of the 〓〓 step instruction, the contents of register #5R are [10・log ₂ (1+2〓 ² )]
It is becoming. Next, determine the size of registers #3R and #4R, add the contents of #5R to the larger one to find the appropriate aperture opening value [10・(AVx+K ₁ )], and set this in register #3R. Next, divide the contents of register #1R indicating the lighting contrast by 10, and calculate the remainder and quotient as
That is, the value obtained by decomposing [10·Δ ₁ ] into the integer part and decimal part of Δ ₁ is decoded by the ROM 24 and displayed on the display device 5 via the terminal (P ₄ ). Next, it is determined whether the content of #3R is within the display limit, and if it exceeds the display limit, the terminal (p ₅ ) is set to "high", while if it is below the display limit, the terminal (p ₆ ) is set to "high". This is displayed on display devices 302 and 304. Next, register #3R which is the aperture opening value
The content of is divided into an integer part and a decimal part, and the decimal part is converted into an apex value while the integer part is converted into an F value using the ROM 24, and displayed on display devices 302 and 304. After that, when switch S is released, the process returns to the start. In this example, only the values for the initially set shutter speed TV and film sensitivity SV are displayed, but the calculated [10.
(BVa+K ₁ )] and [10・(QVf+K ₁ ))] are memorized up to the 〓 command, and if switch S remains on after the output command for display, they will be stored after a certain period of time. [10・(BVa+K ₁ ] and [10・(QVf+
K ₁ )] to registers #3R and #4R respectively,
If you read [10・(10−TV)] into register #1R, read 10・SV into register #1R, and return to the 〓〓 command, the initial setting of TV and SV will be changed. Values can be calculated and displayed without re-measuring. Further, in this embodiment, a dedicated control circuit 100 is used for the timing of photometry and A-D conversion, but these timings can be controlled by a microcomputer without using a dedicated circuit; When calculating various values from the D-converted values, a microcomputer is used in this embodiment, but it is also possible to provide a dedicated circuit for each. FIG. 10 shows another embodiment of the invention using a microcomputer. (Ic) is the constant current circuit (R ₁ ) is the adjustment resistor PD is the photodetector, (D ₁ )
is a logarithmic compression diode, and (OA ₁ ) is an operational amplifier. 200 is a high-pass filter that passes only AC components of a certain frequency or higher; 202 is a high-pass filter that logarithmically expands the output voltage of the high-pass filter 200 into a current, integrates this current, and outputs a voltage obtained by logarithmically compressing the integral amount to both ends of the capacitor C. This is an integrator circuit. A specific example of the above circuit is shown in FIG. Switch S is a switch linked to a photometry button (not shown), and the first push turns it ON, and the second press turns it OFF. (PUC) is a terminal that becomes “High” for a certain period of time when the power is turned on. Reference numeral 110 denotes a timing control circuit, a specific example of which is shown in FIG. The operation of the timing control circuit 110 shown in FIG. 16 will be explained below. When the power is turned on, the terminal (PUC) becomes "High", flip-flops FF ₁₀ and FF ₁₂ are reset, and at the same time a reset signal is sent from the OR circuit (OR ₅ ) to the microcomputer via the terminal (p ₀ ). Ru. At this point, the terminals (p ₁₂ ) and (p ₁₄ ) are "Low", so the outputs of the exclusive OR (EO ₅ ) and (EO ₇ ) are both "Low", and the transistor (FT ₁ ) ，
(FT ₂ ) is “ON” and (FT ₃ ) is “OFF”. When the photometry button is pressed, the switch S turns "ON", the flip-flop (FF ₁₂ ) is set, the terminal (p ₁₀ ) becomes "High", and the exclusive OR (EO ₅ ) and (EO ₇ ) are Both outputs become “High” and the transistors (FT ₁ ) and (FT ₂ )
is “OFF” and (FT ₃ ) is “ON”. Note that since the flip-flops (FF ₁₀ ) and (FF ₁₂ ) are synchronized with the rising signal, the flip-flop (FF ₁₀ ) remains reset. When the photometry button is pressed and the terminal (p ₁₂ ) becomes “High” after a certain period of time, the output (γ ₇ ) of the exclusive OR (EO ₅ ) becomes “Low” and the transistor (FT ₁ ) turns “ON”. , (FT ₃ ) becomes “OFF”. When the metering button is pressed again, the switch S turns "OFF", the flip-flop (FF ₁₀ ) is set, and this rising signal is sent to the flip-flop (FF ₁₂ ) via the OR circuit (OR ₅ ).
The flip-flop (FF ₁₂ ) is reset by the input to the reset terminal of the microcomputer at the same time via the terminal (p ₀ ). Then, since the terminals (p ₁₂ ) and (p ₁₄ ) become “Low”, the terminal (γ ₅ ) becomes “High” and the terminal (γ ₇ ) becomes “Low”, and the transistors (FT ₂ ) and (FT ₁ ) is “ON” and (FT ₃ ) is “OFF”. Furthermore, with the signal rising to "High" from the terminal (Q) of the flip-flop (FF ₁₀ ), a signal that remains "High" for a certain period of time is output from the one-shot circuit (OS ₀ ), and this signal becomes "Low". When the signal goes down, the one-shot circuit (OS ₂ ) outputs a signal that becomes "High" for a certain period of time, and when this signal rises to "High", the flip-flop (FF ₁₀ ) is reset via the OR circuit (OR ₄ ). Ru.
Therefore, all circuits are reset to the same state as when the power was turned on and wait for the metering button to be pressed again. The configuration of FIG. 15 will be explained again. Switch S ₂ is a switch linked to a slide member (not shown) that outputs a signal to change the amount of light received by the flash during the calculation process. When the slide member is slid once to the "UP" side, the signal output circuit 310 outputs 1 EV. A signal corresponding to increasing the amount of light emitted per minute is output,
If you slide it once to the “DOWN” side, a signal corresponding to a reduction of 1 EV will be output. A more detailed explanation will be given according to FIG. In Figure 17, when the power is turned on, the up-down counters (CO ₆ ) and (CO ₈ ) are (PUC)
It is reset by a signal from the terminal. When the slide member is slid once to the "UP" side, the switch (S ₂ ) is connected to the U terminal, and one clock pulse is output from the one shot circuit (OS ₄ ). At this time, up-down (CO ₆ ), (CO ₈ )
Both outputs are “00”, OR circuit (OR ₇ ), (OR ₉ )
The output is “Low” NAND circuit (NAN ₀ ),
(NAN ₂ ) output is “High”, so
The clock pulse from the one shot circuit (OS ₄ ) is input to the UP terminal of the counter (CO ₆ ) via the AND circuit (AN ₆ ), and the output becomes "01". On the other hand, since one input terminal of the AND circuit (AN ₁₂ ) is “Low”, this clock pulse is not input to the DOWN terminal of the counter (CO ₈ ), and the output of the counter (CO ₈ ) remains “00”. be. Conversely, when the slide member is slid to the "DOWN" side, the clock pulse is input only to the UP terminal of the counter (CO ₈ ), and the output becomes "01". Also, for example, if the output of counter CO ₆ is “10”,
When the output of CO ₈ is "00", if you slide the slide member to the "DOWN" side, one clock pulse will be output from the one shot circuit OS ₆ ,
It is input to the DOWN terminal of counter CO ₆ , and the output of counter CO ₆ becomes "01". On the other hand, inverter
Since the output of IN ₄ is "Low", the gate of AND circuit AN ₁₀ is closed and no clock pulse is input to the UP terminal of counter CO ₈ . Therefore, the output of counter _CO8 remains "00". Further, when the output of the counter CO ₆ or CO ₈ becomes "11", the output of the NAND circuit NAN ₀ or NAN ₂ becomes "Low", and from then on, no clock pulse is input to the UP terminal. As is clear from the above explanation, when the number of times the slide member is slid to the "UP" side is greater than the number of times it is slid to the "DOWN" side, the number of times the slide member is slid to the "UP" side is changed to "DOWN".
The counter is calculated by subtracting the number of times it slides to the side.
The output from CO ₆ and counter CO ₈ remains “00”. In the opposite case, the output of counter CO ₆ is "00", and the output of CO ₈ is the number of times it slid to the "DOWN" side minus the number of times it slid to the "UP" side. The output of this counter CO ₆ and CO ₈ is an AND circuit
A counter output other than "00" is output from a multiplexer circuit composed of AN ₁₄ to AN ₂₀ and OR circuits OR ₁₁ and OR ₁₃ . This output P ₂₂ and the output p ₂₀ of the OR circuit OR ₉ are input to the display circuit 500,
Displays the number of EVs to increase or decrease the amount of light received by the flash light when calculation is performed. Further, the decoder 320 outputs a binary number multiplied by 10 from the output of the multiplexer circuit, and this output P ₁₀ and the output p ₂₀ of the OR circuit OR ₉ are input to the I/O port 460. Furthermore, a reset switch is provided, and the signal from this switch and the PUC signal are input to an OR circuit, and the output of this OR circuit is used to control the counters CO ₆ and CO ₈ .
may be reset. The configuration shown in FIG. 15 will be explained again. Switch S ₃
is a switch for switching between aperture priority and exposure time priority, and 330 is an aperture setting device, which outputs a binary number that is 10 times the apex value AVs of the set aperture value. 340 is an exposure time setting device which outputs a binary number obtained by adding a constant _K5 to the set exposure time TVs and multiplying the sum by 10. 350 is a multiplexer, and when the switch S ₃ is connected to the A terminal and the terminal p ₂₂ is "High", the data corresponding to 10 AVs from the aperture setting device 330 is output to the terminal P ₁₂ , and the switch S ₃ When the terminal P ₂₂ connected to the T terminal is “Low”,
[10・(TVs+
K ₅ )] is output to terminal P ₁₂ .
360 outputs a value 10.SV which is 10 times the film sensitivity apex value set by the film sensitivity setting device. 510 is a device for displaying the appropriate aperture value or appropriate exposure time; in the case of the aperture value, the integer part of the apex value is displayed as FNO, and the decimal part of the apex value is displayed as an apex value in units of 0.1 EV.
In the case of exposure time, the integer part of the apex value is displayed as the time, and the decimal part is displayed as the apex value in units of 0.1 EV. Furthermore, when overexposure occurs, "〓〓" is displayed, and when underexposure occurs, "〓〓" is displayed. 520 is the amount of light received by flash only QVf or the appropriate aperture value AVf by flash only
For QVf, the apex value is displayed; for AVf, the integer part is FNO and the decimal part is the apex value. Further, when the amount of light received by the flash is equal to or greater than a predetermined value, "–〓" is displayed, and when it is less than the predetermined value, "〓〓" is displayed.
The switch _S4 is a switch for changing the display value of the display device 520, and when connected to the A terminal, the aperture value AVf is displayed, and when connected to the Q terminal, the received light amount QVf is displayed. 530 is a device for displaying lighting contrast as an apex value. Reference numeral 540 denotes a device that displays the contrast between a portion irradiated with flash light and a portion not irradiated with flash light, or the amount of contribution of flash light due to irradiation of flash light, as an apex value. Further, this display device displays "〓〓" when steady light hardly contributes to exposure, and displays "〓〓" when flash light hardly contributes to exposure. 550 is an over-exposure display device, for example, when two display elements are on and the A-D conversion result of the amount of light received by flash light overflows, it blinks with a signal from one of the display elements _p26 , and When the D conversion value overflows, the other display element is lit by a signal from terminal _p25 . 560 is an under-exposure display device, when the A-D conversion value of the amount of light received by flash light is 0, one display element blinks with the signal from terminal _p28 , and when the A-D conversion value of the constant light is 0. terminal p ₂₇
The other display element lights up with a signal from the display element. 570
is a device that displays the magnitude of the contribution of flash light and constant light to exposure; when the contribution of constant light is greater, the display element lights up in response to a signal from terminal _p30 . 44
0 is the CPU section of the microcomputer, which contains an 8-bit register accumulation register (ACC), general-purpose working registers #OR to #5R, carry flag CY, and zero flag ZF, as well as a logic operation section, address control section, Although there is an instruction control section, a timing control section, etc., they are omitted because they are not directly related to the explanation of this invention. In addition, the general-purpose register is a 16-bit pair register #OPR with two registers connected in series.
~ #4 Can also be used as PR. 41
0 is a RAM that temporarily stores data during the calculation process of the CPU 440. 420 is a ROM for storing instructions and fixed data;
60 is an input/output port I/OP. Note that, in the illustrated microcomputer, parts necessary for explaining the invention are simplified. Figures 18-1 to 18-6 are flowcharts showing the operation of the microcomputer in Figure 15.
The operation shown in FIG. 15 will be explained below according to this flowchart. When the power is turned on, the PUC terminal becomes “High” for a certain period of time and the timing control circuit 11
The microcomputer is reset by the signal at terminal _P0 from 0 to start operation. With this reset signal, the flag in the CPU440 becomes "0", all registers become "00H", all contents of RAM410 become "00H", all outputs of I/OP460 become "0", and operation starts from the instruction at the start address. do. Further, the counter shown in FIG. 15 is also reset by a signal from the PUC terminal. Terminal in step #1
Wait until _p10 becomes "1". That is, switch S
is connected to the ON terminal and waits for the flash to be emitted. When switch S is connected to ON terminal, #2
Step 1 and count the time T ₁ sec. This T ₁ sec is longer than the time required for all types of flash emitters to emit full light.
When _{the switch} S is connected to the ON terminal, the signal from _the ting control circuit 110 terminal τ ₅ turns the transistor FT ₂ off. The voltage generated only by the flash light that has passed through is input to the integrating circuit, and the voltage across the capacitor C is a logarithmically compressed voltage of the amount of light received only by the flash light.
QVf is output. After step #2 is completed,
The terminal _p16 is set to "High" to cause the A/D conversion circuit 22 to start A/D conversion, and to start counting the time T ₂ sec. When this time count ends, the A-D conversion has ended. And the terminal
With _p16 set to "Low", it is determined in step #6 whether the overflow terminal _p18 of the AD converter 22 is "High". In case of overflow,
Move to step #7 and set terminal _P26 to “High”
As a result, the display element in the over display device 550 is blinked. Next, in step #8, terminal P ₁₆
The data necessary to display "〓〓" in the segment display is output and displayed on the display device. This specific method, for example, sets data at a specific address of ROM420 in #4PR, and then uses this #4PR to
Specify the address of , move the data necessary for display stored at this address to the accumulator ACC,
There is a method that outputs the contents of this accumulator to terminal _P16 . Next, “FF _H ” is #ORed.
Set it to address _M1 of RAM410 and move on to step #14. In step #6, if the A-D conversion result does not overflow, the A-D converter 22
Take the output P ₁ of #OR. Next, in step #11, determine whether the content of #OR is “ _00H ”,
When #OR≠ _00H , move to step #14,
#When OR=00H, set terminal _P28 to “High” and blink the display element in the under display device.
The display device 520 displays 〓〓, and the process moves to step #14. With the above steps, the acquisition of the digital value 10·QVf, which is 10 times the amount of light received by the flash, is completed. To obtain the value of QVf multiplied by 10, A
This is possible by appropriately setting the circuit constants of the -D converter 22. Next, in step #14, when terminal _P12 is set to "High", terminal _τ7 becomes "Low", and the transistor
FT ₁ becomes “ON” and FT ₃ becomes “OFF”. Next, data 17・SV from terminal P ₃ and 10・SV from terminal P ₁₄ .
Import data compatible with AVs or 10/[TVs+K ₅ ] into #2R and #3R, respectively. Then, set the terminal _P16 to "High" to start A-D conversion and count the time of T ₂ sec, and when the count is finished,
With terminal P ₁₆ set to “Low”, overflow terminal
Make the determination on page ₁₈ . When _P18 is “High”,
Over display device 55 with terminal P ₂₅ set to “High”
The display element in 0 is turned on, "〓〓" is displayed on the display device 510, and the process moves to step #23. #twenty three
In step , a “Low” signal is output to terminal _P27 . This is because the terminal _P27 may be "High" until the return command, which will be described later.
At this time, both terminals p ₂₅ and p ₂₇ become “High”,
This is to prevent both over-display and under-display elements from lighting up. next,
#The content of OR, that is, [10・QVf] is Odo or 0
If it is over or 0, return to step #15. Also, even if [10・QVf] is 00 _H
If it is not FF _H , set FF _H to #1R,
Jump to step #56. If the overflow terminal _P18 is “Low” in step #20, move to step #29,
The output _P1 of the A-D conversion circuit 22 is taken into #1R.
This data corresponds to [10·(BVa+K ₅ )].
Determine whether this data is _00H , and if it is _00H ,
At step #31, output a “Low” signal to _P25 ,
Set P ₂₇ to “High” to light up the display element of the under display device 560, and then display the contents of #OR [10・
QVf] is over or 0. If it is over or 0, 〓〓 is displayed on the display device 510 and the process returns to step #15, and the following operations are performed according to the flowchart. Also, [10・QVf]
If is not over or 0, jump to step #56. If the contents of #IR are not _00H at step #30, move to step #37 and connect terminals P ₂₅ and P _27.
Outputs a “Low” signal to This step is
Similar to steps #23 and #31, P ₂₅ and P ₂₇ are set to "High" during the previous operation process and are provided to turn off the display element when it is on. Next, determine whether the content of #OR [10・QVf] is over or 0, and if it is neither, jump to step #56. If [10・QVf] is over or 0, #40
Proceed to the step , add the contents of #IR and #2R, and set to #1R. This is [10・
(BVa+K ₅ )+10・SV=10・(EVa+K ₅ )]. Next, [10・(EVa+K ₅ )−10・AVs=
10・(TVa+K ₅ )] or [10・(EVa+K ₅ )−10・
(TVs+K ₅ )=10・AVa]. next,
Determine whether terminal p ₂₂ is “High” and set it to “High”
When , switch S ₃ is connected to the A terminal and the aperture value is
AVs has been set, and the value found in step #41 corresponds to [10·(TVs+K ₅ )]. This value is the shortest exposure time [10.
(TVmax+K ₅ )], and if it is larger, move to step #47.
is displayed on the display device 510, the data at address _M1 of the RAM 420 is moved to #OR, and the process moves to step #15. In the steps described so far, the data at address _M1 is FF _H or 00 _H according to step #9'. At step #43, the contents of #1R are changed to [10・
(TV _nax + K ₅ )] In the following cases, it is next determined whether the carry flag is set to 1, that is, whether the calculation result of step #41 is negative,
If it is negative, the contents of address _M1 of the RAM 410 are set to #OR, 〓〓 is displayed on the display device 510, and the process moves to step #15. If the carry flag is 0 in step #44, data corresponding to the calculated TVa is displayed on the display device 510, and the process returns to step #15. Here, to display #45, divide the contents of #1R by 10, specify the ROM420 address corresponding to the quotient data, that is, the integer part of the apex value, and read the time display data stored there. This data is output to _P14 , and the remainder of the division, that is, the data corresponding to the decimal part of the apex value, is also required to specify the ROM address and display the segment of the apex value stored there. The data is also output to _P14 and the decimal part is displayed. When P ₂₂ is “Low” in step #42, the calculated value corresponds to [10・AVa], and in this case, the value is also compared with [10・AVmax] and the carry flag is determined. , the decimal part is displayed on the display device 510 as 〓〓 or 〓〓 or FN ₀ , and the process returns to step #15. Here, in step #52,
Similar to step #45, input the integer part data.
Convert to FN ₀ display via ROM, decimal part is also ROM
The apex value is displayed as is. Step #56 is a transition from steps #27, #34, and #39. At this point, the content 10/QVf of #1R is neither over nor 0. In step #56, the data from _P10 , that is, the switching amount of flash light amount [10·Δf] is imported into #4R.
Next, the content 10/QVf of #OR is moved to address _M1 of RAM410, and it is determined whether the terminal _P20 is "High" or "Low". When it is “High”, it corresponds to reducing the amount of light emitted by the data from terminal _P10 , and in step #59, calculate [10・QVf−10・Δf=10・QVf′] and use this result. #Set to OR. Next, in steps #60 and #61, it is determined whether the calculation result in #59 is negative or 0. If it is negative or 0, 〓〓 is displayed on the display device 520, and the terminal
Outputs “Low” signal to P ₃₀ . This step is
Has the same meaning as steps #23, #31, #37,
Before this step, the display element in the device 570 that displays the magnitude of the steady light and the flash light may have been turned on, so it is necessary to turn off the display element at this step. Next, in step #64, the contents of #1R [10・
(BVa+K ₅ )] is OO _H , and if it is OO _H , 〓〓 is displayed on the display device 510, and the RAM 410
Move the data corresponding to 10・QVf stored at address _M1 of , to #OR and return to step #15. At step #64, [10・(BVa+K ₅ )] is
If it is not OO _H , then determine whether the content of #1R is FF _H , and if it is FF _H , move the data corresponding to 10・QVf stored in RAM410 to #OR and return to step #15. . At step #65,
If the content of #1R is not FF _H , return to step #40, perform the above-mentioned calculation using the constant light, display the aperture value or exposure time, or 〓〓〓〓〓〓 on the display device 510, and read the information in the RAM 410. Move the data corresponding to 10・QVf stored at address _M1 to #OR and return to step #15. At step #58, if terminal P ₂₀ is “Low”, move to step #69 and perform the calculation [10・QVf+10・Δf=10・QVf′], set this data to #OR, and perform this calculation. Determine whether the data is larger than [10・QVfmax], that is, the fixed data corresponding to the maximum value of QVf,
If it is large, set the terminal P ₃₀ to “Low” with step #71.
Outputs the signal, displays 〓〓 on the display device 520, returns to step #64, and displays 〓〓 or the appropriate exposure time on the display device 510 using only constant light. After performing [10.
Set the data corresponding to [QVf] to #OR and #15
Go back to step. As described above, the operation of steps #53 to #73 is as follows: By changing [10・QVf] by Δf, [10・QVf'] becomes 0 or becomes larger than [10・QVfmax]. This corresponds to the behavior when you become old. [10・QVf′] is larger than 0, [10・QVf′]
QVfmax], move to step #74. In step #74, set the contents of #OR [10・QVf′] to address _M2 of RAM410,
Next, perform the calculation [10・QVf′+10・SV=10・AVf], set this data to #OR, and check whether the terminal _p24 is “High” or “Low” in step #76. Q: Is switch S ₄ connected to the F terminal?
Determine whether it is connected to the terminal. When connected to the F terminal, step #78 sets the AVf
The FNo and the decimal part of the apex value corresponding to the QVf' are displayed on the display device 520, and when connected to the Q terminal, QVf' is displayed as the apex value in units of 0.1EV in step #77. Next, it is determined whether the content of #1R is OO _H , and if it is OO _H , the
Display FN ₀ and the decimal part as an apex value on the display device 510, output a "Low" signal to the terminal _P30 ,
Set the data corresponding to [10・QVf] stored in RAM410 to #OR and return to step #15. Also, if the content of #1R is not OO _H ,
It is determined whether the content of step #1R of #80 is FF _H or not, and if it is FF _H , the operations from #82 onwards are performed in the same way as described above. If the content of #1R is not FF _H at step #80, move to step #84 and read the content of #1R [10.
(BVa+K ₅ )] to address _M3 of RAM410, and then move [10・(BVa+K ₅ )+10・SV=10・(EVa+
K ₅ )], [10・(EVa+K ₅ )−10・(TVs+K ₅ )=
10・AVa] or [10・(EVa+K ₅ )−10・AVs=
10·(TVa+K ₅ )] and determines whether the terminal _P22 is "High" or "Low" in step #87. When set to "High", priority is given to aperture, so go to step #89; when set to "Low", priority is given to exposure time, so go to step #128. In step #89, it is determined whether the contents of #1R, that is, [10・(TVa+K ₅ )] is larger than the data of [10・(TVmax+K ₅ )] corresponding to the shortest exposure time, and if it is, the terminal Output a "Low" signal to _P30 , display 〓〓 on the display device 510, move 10.QVf to #0R, and return to step #15. [10・(TVa+
K ₅ )] is smaller than [10・(TVmax+K ₅ )], then it is determined whether or not [10・(TVa+K ₅ )] has become negative, and if it is negative, that is, the carry flag is 1. Then, the terminal _P30 is set to 0, 10·QVf stored in the RAM 410 is transferred to #0R, 〓〓 is displayed on the display device 510, and the process returns to step #15. If the calculation result [10・(TVa+K ₅ )] is not negative, go to step #95 to determine the appropriate aperture value [10・AVf] and the set aperture value [10・AVs] using only the flash.
If the data corresponding to [10・AVf] is larger than [10・AVs], overexposure will occur, so a “Low” signal is output to terminal P ₃₀ and the display device Display 〓〓 on 510,
Set [10・AVf] to #0R and return to step #15. In step #95, if the data corresponding to [10・AVf] is smaller than [10・AVs], in step #97, calculate [10・AVs−10・AVs=10・Δ ₃ ], Set this data to #3R.
Next, constant _K6 is set to #2R, and the data stored at the address of the ROM 420 specified by the 16-bit contents of #2PR is set to #0R. This #0R
The data to be set is stored in advance in the ROM520 according to Table 1 above [−10・log ₂
(1-2 ^- 〓 ³ )]. That is,
At address K ₆ +10・Δ ₃ of ROM520, [−10・log ₂
(1-2 ^- 〓 ³ )] is stored. The contents of this 0R and the contents of #1R [10・(TVa
+K ₅ )] is added, and [10・(TVa+K ₅ )−10・
log ₂ (1-2 ^{- 3} )=10.(TVx+K ₅ )] is performed, and this data is set to #0R. Next, in step #101, determine whether [10・(TVx+K ₅ )] is larger than [10・(TVmax+K ₅ )] corresponding to the shortest exposure time, and if it is larger, proceed to steps #90 and below. and return to step #15. [10・(TVx+K ₅ )] is [10・
(TVmax+K ₅ )] In the following cases, the exposure time and the decimal part of the apex value are displayed on the display device 510.
Continued to be stored in RAM410 [10・
(BVa+K ₅ )] is set to #1R, 10・QVf′ is set to #2R, data corresponding to [10・SV] from terminal P ₃ is set to #3R, and [10・QVf′+10・SV= Ten·
AVf] and set this data to #4R. Next, based on the calculated appropriate exposure time, calculate the appropriate aperture value for steady light only at this exposure time [10・AVa=10・(BVa+ _K5 )+10・SV−
10・(TVs+K ₅ )] and set this to #5R. In steps #109 and #110, it is determined whether the calculation result in step #108 is less than or equal to 0. If it is less than or equal to 0, a "Low" signal is sent to terminal _P30 .
The signal is output, QVf' is displayed as an apex value on the display device 530 as a lighting contrast, and the 10.
Set the QVf data to #0R and return to step #15. In steps #109 and #110, if it is determined that the calculation result is not less than 0, the process moves to step #114 and calculates the contents of #4R and #5R, that is, 10・AVa and 10・AVa.
Compare the size of AVf. Here, [10・AVf
10・AVa], output a “Low” signal to terminal P ₃₀ , perform the calculation of [10・AVf−10・AVa=10・Δ ₂₁ ], and set this data to #1R.
In step #114, if [10・AVf<10・AVa], set terminal P ₃₀ to “High”, display that the constant light contributes more to the exposure than flash light, and then・AVa−10・AVf=10・Δ ₂₁ ] and set this data to #1R. Next, in step #119, data corresponding to the lighting contrast, which is the content of #1R, is displayed on the display device 530 as an apex value. Next, in step #120, the magnitude of [10・AVf] and [10・AVs] is determined again, and when [AVfAVs] is determined, [10・(AVs+3.9−AVf)=10・(3.9−
Δ ₂₁ )], when [AVs > AVf], [10・(AVf+3.9
−AVa=10・(3.9+Δ ₂₁ )] and set it to #3R. This is clear from the explanation in Table 2,
When Δ ₂₁ is smaller than 3.9, [log ₂ (1+2〓 ²¹ )]
becomes 0 if 0.1 is the minimum unit, so [3.9×10
= _27H ] has been added. Conversely, in the case of [AVfAVs], [10・(AVs+3.9−AVf)=10・(3.9+Δ ₂₁ )]
Perform the calculation and set this data to #3R.
Then, when the calculation result is not negative, that is, when the carry flag is 0, set the constant K ₇ to #2R,
Specify the address of ROM420 with #2PR, and write the data stored there [10・log ₂ (1+2〓 ²¹ )] as #0R.
, display this data as an apex value on the display device 540, set the data corresponding to 10・QVf stored in the RAM 410 to #0R,
Return to step #15. Also, if the calculation result of step #121 is negative, 10・AVs and 10・AVs
The magnitude of AVf is determined, and when [AVs>AVf], 〓〓 is displayed on the display device 540, and [AVs<AVf] is displayed.
If so, display 〓〓, set [10・QVf] to #0R, and return to step #15. The steps following #120 correspond to the step of displaying the contrast between the part irradiated with the flash light and the part not exposed to the flash light, or the amount of contribution of the flash light due to the irradiation of the flash light, as an apex value. Here, as is clear from Table 2, the address of ROM420 is calculated by subtracting the larger of AVa and AVf from the smaller of AVa and AVf so that _Δ21 is always negative, and adding 3.9 to this value. is specified and stored there [log ₂ (1+2〓 ²¹ )]
It is designed to display data corresponding to
When Δ ₂₁ is less than −3.9, that is, [Δ ₂₁ +3.9]
When is less than 0, [log ₂ (1 + 2〓 ²¹ )] is less than 0.1, and in this case, if AVf > AVa,
〓〓 is displayed to show that the constant light does not contribute to exposure. When [AVa > AVf], flash light does not contribute to exposure, so 〓〓 is displayed to show that the contrast is 0. If terminal _p22 is “Low” at step #87, jump to step #131. In this case, the exposure time TVs is set. In step #131, it is determined whether the content of #2R is larger than data 10·AVmax corresponding to the minimum aperture value AVmax, and if it is larger, the display device 510 displays
is displayed, a “Low” signal is output to terminal P ₃₀ , and 10.
Set QVf to #0R and return to step #15. Also, if the calculation result of step #86 above is less than 0, QVf' is displayed as an apex value on the display device.
30 and set [10・QVf] to #0R, then return to step #15. When the calculation result in step #86 is [0<10・AVa10・AVmax], the magnitude of AVf and AVa is determined in step #136, and when it is [AVfAVa], a “Low” signal is sent to terminal _P30 . Output [10・AVf−10・AVa
= 10・Δ ₂ , and when AVa > AVf, set terminal P ₃₀ to “High” and evaluate that the effect of constant light is greater, [10・AVa−10・AVf=
10・Δ ₂ ]. Then, in step #141, the lighting contrast Δ ₂ is displayed as an apex value on the display device 530. This completes the lighting contrast display. In step #142, determine the magnitude of AVf and AVa again, and if [AVf > AVa], set [10・(AVa
+3.9)-10・AVf=10・(3.9+Δ ₂ )], [AVf＜
AVa], [10・(AVf+3.9)−10・AVa=
10・(3.9+Δ ₂ )]. If the result of this calculation is 0 or less, similarly to step #124 and below, if AVf>AVa, the display device 540 will be displayed.
, [When AVa > AVf] is displayed, and after the same steps, return to step #15. Also, if the calculation result is greater than 0, set [10・log ₂ (1+2〓 ₂ )] corresponding to the calculation result [10・(3.9+Δ ² )] to #2R, as in steps #128 and below. , this is displayed on the display device 540, and then this value is
Performs an operation to add to the larger value of AVa and AVf. Therefore, [10・AVa+10・log ₂ (1+2〓 ² )=
10・AVx] or [10・AVf+10・log ₂ (1+2〓 ₂ )
=10・AVx] is found. This result is [10・
AVmax] is larger than [10・AVmax].
AVmax], display 〓〓 on the display device 510, set [10・QVf] to #0R, and return to step #15. If it is less than [10・AVmax], AVx is supported. Display the decimal part of the FNo and apex value on the display device 510, and
QVf] to #0R and return to step #15. The reason for returning to step #15 in the above explanation is that
When the steady light BVa changes or the set values (TVs, AVs, SV, Δf) change,
This is because it is necessary to change the displayed value, and therefore, after the display is completed, it is necessary to take in the various data mentioned above again and perform calculations. When the measurer presses the metering button again, the switch S
is connected to the OFF terminal, and the timing control circuit 110 outputs a reset signal from the terminal _P0 , as detailed in the explanation of FIG.
The microcomputer is reset and all displays except the Δf display disappear, and the transistor
FT ₁ and FT ₂ are “ON” and FT ₃ is “OFF”,
Return to the state when the power was turned on. In the above embodiment, the total amount of incident light during flash photography is not displayed, but this value can also be displayed. That is, if the apex value of the set or calculated exposure time is TV, and the apex value of the total amount of light is QVt, then the relationship 2 ^QVt = 2 ^QVt + ^{2 BVa-TV} holds true. Therefore, using the same procedure as above, we can obtain the relationship QV=(BVa−TV)+log ₂ (1+2〓 ⁷ ) Δ ⁷ =QVf−(BVa−TV), so we can calculate Δ ₇ from QVf and (BVa−TV). QVt can be obtained by adding log ₂ (1+2〓 ⁷ ) corresponding to this Δ ₇ and (BVa−TV). As described in detail in the above embodiments, according to the present invention, an appropriate aperture value can be obtained that takes into consideration the constant light during flash photography without continuing metering during the set exposure time, and Even when the original exposure time or film sensitivity is changed, the flash output level is switched, or the brightness of the ambient light changes, the new optimum value can be adjusted without having to fire the flash again and re-measure the light. This makes it possible to easily and accurately obtain a desired aperture value.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of the present invention, FIG. 2 is a block circuit configuration diagram showing a first embodiment of the present invention,
3, 4, and 5 are block circuit diagrams showing other embodiments of the circuit for determining the amount of strobe light emitted in FIG. 7 is a block circuit diagram showing another embodiment of the circuit for determining the appropriate exposure time. FIG. 8 is a block circuit diagram showing another embodiment of the circuit for determining the appropriate exposure time. , FIG. 9 is a circuit diagram showing a second embodiment of the circuit of the photometry section, FIG. 10 is a block circuit diagram showing a third embodiment of the circuit of the photometry section, and FIG.
12 is a circuit diagram of the control circuit in FIG. 11, FIG. 13 is a time chart of each signal in FIG. 11, and FIG. 14 A, B, and C are the diagrams in FIG. 11. A flowchart of a microcomputer, FIG. 15 is a block circuit configuration diagram showing a third embodiment of the present invention, and FIG.
Circuit diagram of the timing control circuit in Figure 1.
Figure 7 is a circuit diagram of the signal output circuit in Figure 15, and Figure 18 is a circuit diagram of the signal output circuit in Figure 15.
1-6 are flowcharts of the microcomputer of FIG. 15, respectively. Ps... Flash, Pa... Steady hole, S... Photometering switch, 7... Strobe device, 1... Timing controller, 3... Display circuit, 4... Arithmetic circuit,
PD...Photodetector, 20...Photometric circuit, C...Capacitor, 22...A-D converter, 30, 32,
34, 34...Circuit, 40,50,82...Addition/subtraction circuit, 60...Multiplexer, 62,64,
70, 78, 84, 90...addition circuit, 400...
...Microcomputer, 110...Timing control circuit, 310...Signal output circuit.

Claims (1)

[Scope of Claims] 1. In a photometer for flash photography that determines an appropriate aperture value for the sum of the amount of steady light and the amount of flash light received within a set exposure time, the flash light emitted in advance prior to the flash light emission during shooting. a first means for obtaining a first signal by integrating the photometric output for a predetermined integration time including time; a second means for obtaining a second signal indicating the steady light intensity based on the photometric output when the flash is not emitting light; a third means for obtaining a third signal including information only on the amount of flash received light integrated within the integration time, based on the information on the integration time, the first signal, and the second signal; and information on the set exposure time. a fourth means for outputting a fourth signal containing information on film sensitivity; a fifth means for outputting a fifth signal containing information on film sensitivity; and determining an appropriate aperture value based on the second, third, fourth and fifth signals. A photometric device for flash photography, characterized in that it has a sixth means for calculating.