JPS642928B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to a photometric device for flash photography. BACKGROUND TECHNIQUES Conventional photometry methods for flash photography continuously measure light during a preset exposure time.
This integrated light amount was used to obtain the exposure control value necessary for flash photography. For this reason, it has been impossible to obtain an appropriate exposure time for flash photography by setting the aperture value. Purpose Therefore, an object of the present invention is to provide a photometry device for flash photography that can perform photometry for a certain period of time and obtain an appropriate exposure time that takes flashlight and ambient light into consideration. That is, the photometry device for flash photography according to the present invention performs photometry on a subject irradiated with light including a flash emitted in advance, and obtains a photometry value corresponding to the amount of received flash light related to the amount of flash light emitted. means for outputting a signal corresponding to information on the intensity of only the stationary light based on photometry of only the stationary light that is not affected by flash; a signal corresponding to the information on the intensity of the stationary light only; and a set exposure. a calculation means for calculating information on the amount of light received based only on the steady light within the set exposure time according to the time; A means for setting a converted value, and information corresponding to the ratio of the total amount of light received within the set exposure time to the amount of light received based only on steady light based on the calculation result of this calculation means, the photometric value, and the converted value. By providing a display means for displaying the information, the intended purpose can be achieved. 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 with reference to FIG. As shown in Figure 1, the photometry time when the flashlight is fired is t ₁ (TV ₁ in apex value), and the photometry time is t ₂ (in apex value) when there is only stationary light.
TV ₂ ), the photometric output when the flash Ps(t) is emitted is QVfa, and the photometric output when only the steady light Pa is used.
QVa. Further, when the flash Ps(t) is emitted, the photometric output when the steady light Pa is set to 0, that is, the photometric output due to only the flash Ps(t) as the amount of flash light is defined as QVf. Furthermore, the apex value of the light intensity, which can only be determined by steady light, is used as the instantaneous light intensity.
When BVa is used, the photometric outputs QVfa and QVf have the following relationship. 2QVfa=∫ ^t1 ₀ {Ps(t)+Pa}dt =2QVf+2BVa−TV1 …(1) 2QVa=∫ ^t2 ₀ Padt=2Bva−TV ₂ …(2) QVa=BVa−TV ₂ …(2−1) So Δ1 If we define Δ1≡QVfa−(BVa−TV ₁ ) …(3) and eliminate BVa−TV ₁ from equation (1), we get 2QVf=2QVfa(1−2 ⁻ 〓 ¹ ) …(4), and both sides By taking the logarithm of , we obtain the relationship QVf=QVfa+log2(1-2 _- 〓 ₁ )...(5). Note that BVa−TV ₁ is BVa
−TV ₁ = QVa+TV ₂ −TV ₁ . Here, when calculating equation (5), BVa−TV ₁ is eliminated, but QVfa is eliminated, and QVf=(BVa−TV ₁ )+log2(2〓 ₁ −1)
...(5-1) and then calculate log2(2〓 ₁ - 1) for Δ _{1.Furthermore} , it is also possible to define it as (BVa-TV ₁ )−QVfa≡Δ11 ...(3-1) QVf can be found using the following procedure. Also, to find QVf, it is not necessary to use the above calculation; as is well-known,
If a high-pass filter is connected to the photometric output when a flash is emitted, the steady light component will be cut out from the high-pass filter and only the flash component will be output, and QVf can be found by integrating this output. Next, the principle of determining the appropriate exposure time TVx when the aperture value AVs and film sensitivity SV are set will be explained. Generally, the conditions for proper exposure when firing a flash are 2SV・(2QVf+2BVa−TV)=2AV
...(6-1) Furthermore, the conditions for proper exposure when only flash light is irradiated are 2QVf+SV=2AVf (6-2), where AVf is the appropriate aperture value when only flash light is irradiated. Here, if the aperture value AVs and film sensitivity SV are set, the above equation (6-1) becomes as follows. 2SV・(2QVf+ZBVa−TVx)=2AVs
...(6-3) By the way, since QVf is determined as described above, AVf is also determined from the above equation (6-2). Therefore, by defining Δ ₂ ≡AVs−AVf …(7) and eliminating AVf from the above equation (6-3),
By taking the logarithm of both sides and rearranging, we find TVx=TVa−log2(1−2 ^- 〓 ² )...(8). Here, TVa=BVa+SV-AVs. Note that when AVs-AVf<α (α>0), the exposure time becomes shorter than the shortest seconds, so it is necessary to display overexposure. Furthermore, when calculating the above equation (8), AVf was eliminated, but
If AVs is deleted, TVx = BVa + SV - AVf - log2 (2〓 ² -1)
...(8-1) is found. Furthermore, it can be found in the same way as Δ2′=AVf−AVs. The above TVx can also be obtained as follows. First, considering QVfa shown in the above equation (1) as the amount of light emitted by one flash, AVfa=QVfa+SV (9) is obtained. When AVfa is calculated, the above formula (6-3) becomes: 2AVfa + 2BVa + SV - TVx ₁ = 2AVs
...(6-4) Here, 2 ^-TVx1 corresponds to the time from the time when the flash light emission ends until the exposure time determined by TVx ends. Therefore, first, calculate TVx ₁ based on the above formula (6-4), and then calculate from TVx ₁ and TV ₁ .
All you have to do is find TVx. In other words, by defining Δ3≡AVs−AVfa...(7-1), from equations (6-4) and (7-1),
By eliminating and rearranging AVfa and taking the logarithm of both sides, TVx ₁ = TVa−log2 (1−2 ⁻ 〓 ³ ) …(8−2) is obtained. On the other hand, the following relationship holds between TVx ₁ , TV ₁ and TVx: 2-TVx=2-TVX1+2-TV1 (10). Therefore, we define Δ4≡TV ₁ −TVx ₁ …(11), eliminate TV ₁ from the above equation (10), and rearrange it as follows.
By taking the logarithm of both sides, TVx=TVx ₁ −log2 (1+2 ⁻ 〓 ⁴ ) …(8-3) is found. In addition, when switching the flash light emission amount, if the switching amount Δf is set, the flash light emission amount is QVf − Δf = QV′f …(12), and TVx is calculated based on this QV′f. This makes it possible to obtain an appropriate exposure time when performing flash photography by switching the amount of flash light emitted in advance. On the other hand, based on the above appropriate exposure time TVx, lighting contrast, which is an apex-based representation of the difference in the effects of flashing light and steady light on the subject, can be determined. That is, the lighting contrast is expressed as Δ5=QVf−(BVa−TVx) (13) Since QVf, BVa, and TVx have already been determined, Δ5 can also be determined. In addition, there are parts of the photographic screen that are irradiated with flash light and steady light, and parts that are not irradiated with flash light and are only irradiated with steady light. At this time, the exposure time
The total amount of light 2QVt in the portion of TVx that is illuminated by flash and steady light is expressed as 2QVf + 2BVa - TVx = 2QVt (14). Further, the contrast between the above two parts is expressed as Δ6=QVt−(BVa−TVx) (15). Therefore, first of all, the above two equations (13),
According to (14), by eliminating QVf from equation (14) and taking the logarithm of both sides, QVt=BVa−TVx+log2(1+ ^2〓5 )...(16) is found. As is clear from equations (15) and (16) above, Δ6=log2(1+ ^2〓5 )...(17). Also, for a subject illuminated with flash light and steady light, the amount (number of steps) that the subject becomes brighter due to irradiation with flash light is as described above, QVt-(BVa-TVx)=log2(1+ ^2〓5 )
...(17-1) It is shown as follows. As mentioned above, aperture value AVs and film sensitivity SV
It is possible to obtain various values related to exposure control when the flash light emission amount switching amount Δf is set, but here, log2 for the variable x
It is necessary to find the values of (1-2 ^-x ) and log2(1+ ^2x ). The accuracy of the above-mentioned values obtained by measurement and calculation is usually within the unit of about 0.1 EV. Therefore, log2(1-
2 ^-x ) and log2(1+ ^2x ) are calculated in advance during the manufacturing process of the product using this device. This calculated value is
For example, the numbers below the second decimal point may be rounded down. As this circuit device, a decoder, a ROM (read only memory), or a microcomputer that outputs the value of log2 (1-2 ^-x ) or log2 (1+2 _x ) corresponding to x may be used. In particular, when using a microcomputer, it is possible to sequentially determine the area to which x belongs, and when the area to which x belongs is determined, data corresponding to the determined area can be obtained. It is. Note that the value of log2(1+2 _x ) is necessary when the values of β and γ are known and the value of δ that satisfies the relationship 2β+2γ=2δ is required. Here, when β-γ=x, δ=β+log2(1+2 ^-x ) or δ=γ+
It becomes log2(1+ _2x ). By the way, log2 (1 + ₂
becomes smaller than 0.1. Therefore, add 3.9 to the smaller of β and γ, subtract the larger one from this value, and set the value as x′, and log2(1+2 _x ) corresponding to this x′.
is added to the larger of β and γ, log2
Since the value of (1+2 _x ) also falls within the range of 1 to 0.1, it becomes easy to determine δ. Below, the relationship between 10・x and −10・log2 (1−2 ^-x ) and the relationship between 10・(x+3.9) and 10・log2 (1+2 _x ) are shown in Table 1 and in hexadecimal. It is shown in Table 2.
Note that numbers with H added after them are hexadecimal numbers.

【table】

【table】

[Table] Next, a circuit configuration embodying the principle of the invention described above will be described in detail with reference to FIGS. 2 to 18. First, in the block circuit diagram shown in Figure 2, QVfa (the photometric output when the flash Ps(t) is emitted, hereinafter simply referred to as QVfa) and QVa (the constant light
This is the photometric output when only Pa is used, and is simply written as QVa below. ), the configuration for obtaining QV′f (the amount of flash light received after switching the light emission amount, hereinafter simply referred to as QV′f) will be shown. S is a switch linked to a photometry button (not shown), which is closed when the photometry button is pressed, and its closing signal is applied to the strobe device 1, which causes the main discharge tube 1a to emit light. Reference numeral 2 denotes a timing controller that controls the operation of the entire photometering device, and 3 a photometering circuit that includes a light receiving element PD and a light amount integrating capacitor C. This photometry circuit 3
are publicly known, for example, Japanese Patent Publication No. 50-28038.
As shown in the publication, a logarithmically compressed voltage is generated across a capacitor C by integrating a current corresponding to the output current of the light receiving element PD. 4 is an analog-digital converter (hereinafter simply referred to as an A-D converter); 5 outputs data from the A-D converter 4 in response to a signal from a terminal 16 of the timing controller 2; Demultiplexer that switches the terminals for , 6 and 7 are the above outputs respectively
This is a register that stores digital signals corresponding to QVfa and output QVa. 8 is a circuit that outputs a signal corresponding to the number of switching steps when the flash light emission amount is switched by the measurer, and 9 is an apex corresponding to the photometry times t ₁ and t ₂ of the photometry circuit 3 shown in FIG. This is a circuit that outputs fixed data corresponding to the values TV ₁ and TV ₂ . 10 is an arithmetic circuit consisting of an addition/subtraction circuit 11, a subtraction circuit 12, a ROM 13, a subtraction circuit 14, a subtraction circuit 15, etc.
Based on QVfa, QVa, and fixed data TV ₁ and TV ₂ , the amount of flash light QV'f is calculated. In the above configuration, first, when the photometry button is pressed, the switch S is closed, and based on this signal, the main discharge tube 1a of the strobe 1 emits light, and the photometry circuit is activated by a signal from the terminal 10 of the timing controller 2. 3 starts photometry operation. Then, when the photometry operation is stopped by a signal from the terminal 10 after _one hour t, the capacitor C is charged with a voltage corresponding to the output QVfa obtained by logarithmically compressing the amount of light received by the light receiving element PD. When photometry stops, this voltage is converted into a digital signal by the A-D converter 4 in accordance with the signals from the terminals 14 and 16 of the timing controller 2, and sent to the register via the demultiplexer 5. 6 is stored. When the storage in the register 6 is completed, the charge in the capacitor C is discharged by the signal from the terminal 12 of the timing controller 2, and the photometry circuit 3 starts photometry again by the signal from the terminal 10, and after t ₂ hours. Stops photometry operation. When the photometry operation stops, the capacitor C is charged with a voltage corresponding to the output QVa obtained by logarithmically compressing the amount of light received by the light receiving element PD. When photometry is stopped, this voltage is converted into a digital signal by the A-D converter 4 and stored in the register 7 via the demultiplexer 5 in the same manner as described above. When the data QVfa and QVa are stored in the registers 6 and 7, respectively, the arithmetic circuit 10 starts operating in response to a signal from the terminal 18 of the timing controller 2. In the arithmetic circuit 10, the addition/subtraction circuit 11 first calculates [QVa+TV ₂ −TV ₁ =BVa−TV ₁ ] based on the signals from the circuit 9 and the register 7, and the subtraction circuit 12 calculates the above calculation result. Based on the signal from register 6,
[QVfa−(BVa−TV ₁ )=Δ ₁ )] is calculated. When the address of the ROM 13 is specified with the data corresponding to this calculation result Δ ₁ , it is stored at this address [-
log2(1-2 ^{- 〓1} )] is read out. This read output data and the signal from the register 6 are subtracted by the subtraction circuit 14,
[QVfa+log2(1-2 ^{- 〓1} )=QVf], that is, data corresponding to the amount of light emitted by only the strobe light is calculated. The data corresponding to this QVf is the subtraction circuit 1
5, a strobe light emission amount switching step number signal Δf is subtracted from the calculation result QVf.
Therefore, the subtraction circuit 15 calculates the light amount QVf' of only the strobe light at the time of photographing. Note that FIGS. 3, 4, and 5 are block circuit diagrams showing other embodiments for determining the amount of light emission QVf of strobe light, respectively. In FIG. 3, the subtraction circuit 12 calculates [QVfa−(BVa−TV ₁ )=Δ ₁ ], and the ROM2
[log2 (2〓 ¹ - 1)] is output from 0, and the adder circuit 21 outputs [BVa - TV ₁ + log2 (2〓 ^{1 -} 1)
=QVf] is calculated. Also, Figures 4 and 5
In the figure, from the subtraction circuit 22 [(BVa−TV ₁ )−
QVfa=Δ11] is calculated, and the other circuit configurations are the same as those in FIGS. 2 and 3. FIG. 6 is a block circuit diagram showing an embodiment of the present invention in which other configurations are added to the configuration shown in FIG.
The same reference numerals are given. In this block circuit diagram, a film sensitivity setting circuit 25, an aperture value setting circuit 26, and a display circuit 27 are added, and the arithmetic circuit 10 has, in addition to the above configuration,
Addition circuit 28, addition/subtraction circuit 29, addition circuit 30,
It includes a subtraction circuit 31, a ROM 32, an addition circuit 33, subtraction circuits 34, 35, a ROM 36, and an addition circuit 37, respectively. Then, the data QVa from the register 9 and the data corresponding to the apex value TV ₂ from the circuit 9 are added in the adding circuit 28, and the light amount BVa of only the stationary light is calculated. This calculation result BVa,
The data corresponding to the set aperture value AVs and the set film sensitivity SV from the film sensitivity setting circuit 25 and the aperture value setting circuit 26 are added to the addition/subtraction circuit 29.
The appropriate exposure time [TVa (= BVa + SV - AVs)] using only the steady light input is determined. On the other hand, the data corresponding to the light emission amount QV'f of only the flash from the subtraction circuit 15 calculated in FIG.
It is displayed on the display circuit 27 and added to the data corresponding to the set film sensitivity SV in the addition circuit 30 to determine the appropriate aperture value based only on the flash.
AVf can be obtained. Data corresponding to this appropriate aperture value AVf is displayed on the display circuit 27. Data corresponding to this appropriate aperture value AVf and the set aperture value
The data corresponding to AVs is subjected to the calculation shown in the above equation (7) by the subtraction circuit 31, and Δ2 is calculated. With the data corresponding to this calculation result Δ2,
When an address in the ROM 32 is specified, data corresponding to [-log2 (1-2 ^- 〓 ² )] stored at this address is read out. The read output data and the data corresponding to the appropriate exposure time TVa from the addition/subtraction circuit 28 are combined by the addition circuit 33 according to the above equation (8).
The calculation shown in is performed to calculate the appropriate exposure time TVx, and the data corresponding to this appropriate exposure time TVx is displayed on the display circuit 27. Difference between the data corresponding to the appropriate exposure time TVx as described above and the data corresponding to the light amount BVa of only the steady light from the adding circuit 28 [BVa − TVx]
is calculated by the subtraction circuit 34. The data corresponding to this calculation result and the data corresponding to the flash light emission amount QV'f from the subtraction circuit 15 are combined into the subtraction circuit 3.
5, the calculation shown in equation (13) above is performed. Then, borrow signals are output from one output terminal 35a, that is, the above QVf' and the above [BVa-
TVx] is larger, and from the other output terminal 35b, the above equation (13) is output.
Data corresponding to the absolute value of Δ5 is output,
Both are displayed on the display circuit 27. Furthermore, Δ5
When the address of the ROM 36 is specified with data corresponding to , the ROM 36 outputs the contrast between the flashed area and the non-flashed area and the contribution of the flash to photography [Δ6=log2(1+2〓 ⁵ )]
Data corresponding to is read out and displayed on the display circuit 27. Furthermore, the above Δ6 and the above subtraction circuit 3
The data corresponding to [BVa-TVx] from 4 is
The adder circuit 37 adds the data, and the display circuit 27 displays data corresponding to the total light amount QVt. FIG. 7 shows a second embodiment for calculating the appropriate exposure time TVx, and the same components as those in FIGS. 2 to 6 are omitted or the same reference numerals are given to those that need to be shown. . First, data corresponding to the flash light emission amount QVfa from the register 6 and data corresponding to the set film sensitivity SV are added by the adding circuit 40 to calculate data corresponding to AVfa. The difference Δ3 between the data corresponding to this calculation result and the data corresponding to the set aperture value is calculated by the subtraction circuit 41, and from the ROM 42, -log2(1-2 ^- 〓 The data corresponding to ³ ) is read. On the other hand, the adding circuit 28 outputs BVa corresponding to the intensity of the steady light, and the adding/subtracting circuit 29 adds and subtracts the data corresponding to this and the data corresponding to the set film sensitivity SV and the set aperture value AVs. , proper exposure time using only constant light [TVa
= BVa + SV - AVs] is calculated. Then, in the adder circuit 42, the ROM 43,
According to the data from the addition/subtraction circuit 29, TVx ₁ =
The calculation of [TVa−log2(1−2 ^{− 〓3} )] is performed.
Then, when an address in the ROM 44 is specified with the data corresponding to the calculation result TVx ₁ , TVx stored at that address = TVx ₁ - log2 (1-2 ^- 〓 ⁴ )
The data corresponding to is read out. Here, the above formula
Δ4=TV ₁ −TVx ₁ in (11) is a value that is determined because TV ₁ is fixed data, and therefore, the appropriate exposure time TVx is a value that is determined when TVx ₁ is determined. Note that if the operation of the arithmetic circuit 10 shown in FIGS. 2 to 7 is repeated at a predetermined period of time, that is, if a repeated calculation start signal is output from the terminal 18 of the timing controller 2, the setting film Sensitivity SV, set aperture value
Even if the AVs and flash light emission amount switching signal Δf are changed, the photometric values QVfa and QVa are stored in registers 6 and 7, respectively, so new values of the various data mentioned above can be calculated without re-measuring the photometry. be done. Figure 8 shows the apex value BVa of the light intensity of steady light only, and the photometry output QVf of flash light measurement only.
FIG. 2 is a circuit diagram showing an example for determining First, the output of the operational amplifier OA ₁ , that is, the photometric output, is adjusted by the constant current source IC and the adjustment resistor R ₁ . D ₁ is a logarithmic compression diode, and the operational amplifier OA ₁ outputs a voltage obtained by logarithmically compressing the output current of the light receiving element PD by the diode D ₁ and the voltage by the adjustment resistor R ₁ . Until the switch S shown in FIG. 2 is closed, the terminal 10' of the timing controller 2' is at "H" and the terminal 12' is also at "H". Therefore, the P-channel FET (FT ₁ ) is non-conductive, and the N-channel FETs (FT ₂ ) and (FT ₃ ) are conductive. Here, when the switch S is closed, a flash is emitted and the terminal 10' becomes "L", making the N-channel FET (FT ₂ ) non-conductive. Also, capacitors C ₁ , C ₂ , resistors R ₂ , R ₃ , operational amplifier OA ₂
From _the high-pass filter HPF, which consists of
That is, a voltage based only on the light emission amount component of the flash is output. This voltage is applied between the base and emitter of the transistor BT ₁ and is logarithmically expanded to the collector current, and this same current is applied from the collector of the transistor BT ₂ to
Diode D ₂ proposed in Publication No. 28038,
D ₃ and flows into a logarithmic compression integration circuit x composed of a capacitor C ₃ . The voltage across the capacitor _C3 is a value obtained by logarithmically compressing the integrated value of the inflow current, and therefore, this voltage corresponds to the analog signal of the photometric output QVf due to only the flash. After the switch S is closed and after a predetermined time (that is, longer than the time required for all types of flashlights to emit full light), an A-D conversion start signal is output from the terminal 14', and the A-D conversion circuit 4 starts operating, the charging voltage of the capacitor _C3 is converted from analog to digital, and the digital signal corresponding to the above QVf is sent to the register 6 via the demultiplexer 5 in FIG.
is memorized. After this, terminals 10' and 12' become "L",
N-channel FETs (FT ₂ ), (FT ₃ ) are non-conducting, P
After channel FET (FT ₁ ) conducts, A-D
The photometric output from the operational amplifier OA ₁ is applied to the conversion circuit 4 . At this time, the photometric output is an analog signal corresponding to the apex value BVa of the light intensity due to only the stationary light since the flash light emission has ended. When the A/D conversion start signal is output from the terminal 14' again, the analog signal corresponding to BVa is A/D converted, and this digital signal is stored in the register 7. Thereafter, as in the case shown in FIG. 2, the arithmetic circuit 10 calculates the appropriate aperture value AVf based on the amount of steady light only, the appropriate aperture value AVx based on flash light only, the appropriate exposure time TVx, the lighting contrast, Contribution amount of flash and steady light Δ6
etc. are calculated. When all data calculations are completed, the A-D conversion start signal is outputted from the terminal 14' again.
Again, the apex value of the light intensity of the steady light only.
After BVa is A-D converted and stored in the register 6 as new data, calculations are performed.
Therefore, when the constant light changes, new various data described above can be obtained based on the changed value. As described above, compared to the arithmetic circuit 10 shown in FIG. 2, there is an advantage that the number of circuit components is reduced. Figure 9 shows the high-pass filter 45, the capacitors C ₁ and C ₂ of Figure 8, the resistors R ₂ and R ₃ , and the operational amplifier.
The circuit has the same configuration as the circuit configured with OA ₂ , and the integrating circuits 46 and 47 are replaced with the transistors BT 1 and BT ₁ of FIG.
This circuit has the same configuration as the circuit composed of BT ₂ and diodes D ₂ and D ₃ . And in the example of , the voltage across capacitor C ₄ is within a certain time t ₁
The voltage across capacitor _C5 corresponds to the amount of light from the flash alone, QVfa. Moreover, the analog multiplexer 48 outputs one of the two input signals.
and a timing controller 49. In the above configuration, when the switch S in FIG. 2 is closed, the timing controller 4
9 terminals 10'' and 16'' become "H", N channel FET (FT ₄ ) becomes conductive, and terminals 14'' and 1
8" becomes "L" and FET (FT ₅ ), FET (FT ₆ )
becomes non-conductive. Then, the output of the operational amplifier OA ₁ is applied to one integrating circuit 46 via an N-channel FET (FT ₄ ), and simultaneously applied to the other integrating circuit 47 via a high-pass filter 45. Then, switch S is closed and terminal 1 is closed after t ₁ hour.
0" becomes "L", N channel FET (FT ₄ )
becomes non-conductive, and no signal is input to the integrating circuit 46. This t ₁ hour is longer than the flashing time of strobe device 1, so after t ₁ hour,
The output of the operational amplifier OA ₁ does not change, and the output of the high pass filter 45 remains zero. Therefore, at the time when the integration operations of both the integrating circuits 46 and 47 are completed, the voltage across the capacitor _C4 is the voltage corresponding to the photometric output QVfa, and the voltage across the capacitor _C5 is the voltage corresponding to the photometric output QVf. It's summery. t When ₁ hour has passed, terminal 16'' becomes “H”
Furthermore, the terminal 14'' becomes "H", and the voltage across the capacitor _C4 is applied to the A-D converter 4 via the analog multiplexer 48, converted into a digital signal, and output as an A-D signal. Conversion is completed. At this point, terminal 14" becomes "L",
A digital signal corresponding to the photometric output QVf is stored in the register 6 via the demultiplexer 5. When the storage in register 6 is completed, terminal 16''
is “L”, and terminal 14” continues to be “H”.
The voltage across the capacitor _C5 is applied to the A-D converter 4 via the analog multiplexer 48.
After A/D conversion, a digital signal corresponding to the photometric output QVf is stored in the register 7. When the storage in both registers 6 and 7 is completed, the subtraction circuit 50 calculates [QVfa - QVf] = Δ6 based on the signals from both registers 6 and 7, and the data corresponding to this Δ6 is calculated. , ROM51
When the address is specified, data of log2 (2 ^- 〓 ⁶ - 1) corresponding to this Δ6 is read from the ROM 51. This read data and this register 7
The data corresponding to the QVf from
(2〓 ⁶ −1) = BVa−TV ₁ and from the above circuit 9
The adder 53 adds the data corresponding to TV ₁ to calculate (BVa-TV ₁ )+TV ₁ =BVa. Even in the above manner, data corresponding to the apex value BVa of the light intensity determined only by the photometric outputs QVfa and QVf and the steady light can be obtained. From then on,
Various data can be obtained using the circuits shown in FIGS. 2 to 8 described above. In addition, in the above configuration, N-channel FET
If a low-pass filter (not shown) is provided between (FT ₄ ) and the integrating circuit 46, the voltage across the capacitor C ₄ becomes a voltage corresponding to [BVa-TV ₁ ]. Therefore, the subtraction circuit 50 and the ROM 5
1. The adder circuit 52 is not required. Also, Figure 2,
In FIGS. 8 and 9, the case where the photometric circuit 3 is configured with one light-receiving element has been explained, but two light-receiving elements are provided, one for flash light and the other for constant light. You can do it like this. FIG. 10 shows the arithmetic circuit 10 in the above embodiment.
This shows an embodiment equipped with a microcomputer 60, which includes a constant current source IC, an adjustment resistor R ₁ , a light receiving element PD, a logarithmic compression diode D ₁ , and an operational amplifier.
Regarding the logarithmic compression integration circuit x composed of OA ₁ high-pass filter HPE, capacitor C ₃ and integration circuit 61, and N-channel FETs (FT ₂ ) (FT ₃ ),
The configuration is the same as that shown in FIG. A switch S and a terminal PUC are connected to the timing controller 62, and the switch S operates in conjunction with a photometry button (not shown).
The second push turns it on, the second press turns it off, and the terminal PUC remains "H" for a certain period of time when the power is turned on. As specifically shown in FIG. 11, when the timing controller 62 is powered on, the terminal PUC becomes "H" and the flip-flops FF ₁ and FF ₂ are reset via the OR circuits OR ₁ and OR ₂ , respectively. At the same time, a reset signal is applied to the microcomputer 60 from the OR circuit _OR2 .
At this point, the flip-flop FF ₂ is reset and the terminals P ₁₂ and P ₁₄ are at "L".
The outputs of the exclusive OR circuits EO ₁ and EO ₂ both become "L", and the P channel FET (FT ₁ ) and inverter IN ₂ make the N channel (FT ₂ ) conductive and the N channel FET (FT ₃ ) nonconductive. It is becoming. Here, when the metering button is pressed, the switch S
is turned on, flip-flop FF ₂ is set, and terminal P ₁₀ becomes "H", and the outputs of exclusive OR circuits EO ₁ and EO ₂ both become "H" and the P channel FET (FT ₁ ) and N channel FET
(FT ₂ ) is non-conductive, and N channel (FT ₃ ) is conductive. In addition, flip-flop (FF ₁ ), (FF ₂ )
is synchronized to the rising edge signal, so the flip-flop
FF ₁ remains reset by inverter IN ₁ . After a certain period of time after the above photometry button is pressed, the terminal _P12 becomes "H" and the output τ ₁ of the exclusive OR circuit EO ₁ becomes "L" and becomes the P channel.
FET (FT ₁ ) conducts, N-channel FET (FT ₃ )
becomes non-conductive. Subsequently, when the photometry button is pressed again, switch S is turned off, flip-flop _FF1 is set, and this rising signal is input to the reset terminal of flip-flop _FF2 via OR circuit _OR1 . As a result, flip-flop _FF2 is reset, and at the same time, microcomputer 60 is reset via terminal _P0 . Then, since the terminals P ₁₂ and P ₁₄ become "L", the terminal τ ₂ becomes "H", the terminal τ ₁ becomes "L", and the P channel becomes
The FET (FT ₁ ) and the N-channel FET (FT ₂ ) become conductive, and the N-channel FET (FT ₃ ) becomes non-conductive. Further, at the rising edge of the "H" signal from the set output Q of the flip-flop _FF1 , the one-shot multivibrator (hereinafter simply referred to as one-shot circuit) _OS1 outputs an "H" signal for a certain period of time. When the signal from the one-shot circuit OS ₁ falls, the one-shot circuit OS ₂ outputs an "H" signal for a certain period of time, and at the rising edge of this signal, the flip-flop FF ₁ is reset via the OR circuit OR ₁ . Ru. Therefore, all the circuits are reset to the same state as when the power was turned on and wait until the photometry button is pressed again. Again, in FIG. 10, the switch _S2 is linked to a slide member (not shown) and outputs a signal for switching the amount of light received by the flash during the calculation process.
When the slide member is slid once to the "UP" side, a signal corresponding to an increase in the amount of flash light equivalent to 1 EV is output from the switching stage number signal output circuit 63, and when the slide member is slid once to the "DOWN" side, a signal corresponding to an increase in the amount of flash light emitted is outputted from the switching stage number signal output circuit 63. A signal corresponding to a decrease in the amount of flash light equivalent to 1EV is output. More details are shown in Figure 12. When the power is turned on, the up-down counter
CO ₁ and CO ₂ are reset by a signal from terminal PUC. When the slide member is slid once to the "UP" side, the switch _S2 is connected to the U terminal, and one clock pulse is output from the one shot circuit _OS3 . At this time, the up-down counter
Both CO ₁ and CO ₂ outputs are “00”, OR circuit
The outputs of OR ₃ and OR ₄ are “L”, NAND circuit NAN ₁ ,
Since the output of NAN ₂ is "H", the clock pulse from the one-shot circuit OS ₃ is sent to the up-down counter CO ₁ via the AND circuit AN ₁ .
It is input to the UP terminal and the output becomes “01”. On the other hand, one input terminal of AND circuit AN ₂ is “L”
Therefore, this clock pulse is not input to the DOWN terminal of the up-down counter _CO2 , and the output of the up-down counter _CO2 remains at "00".
Conversely, when the slide member is slid to the "DOWN" side, the clock pulse is input only to the UP terminal of the up-down counter _CO2 , and its output becomes "01". Also, for example, when the output of the up-down counter CO ₁ is "10" and the output of the up-down counter CO ₂ is "00", when the slide member is slid to the "DOWN" side, one clock pulse is generated from the one-shot circuit OS ₄ . is output, and the AND circuit
Updown counter CO ₁ through AN ₄
It is input to the DOWN terminal and its output becomes “01”. On the other hand, since the output of the inverter _IN3 is "L", the gate of the AND circuit _AN3 is closed and no clock pulse is input to the UP terminal of the up-down counter _CO2 . Therefore, the output of the up-down counter _CO2 remains at "00". Furthermore, when the output of up-down counter CO ₁ or CO ₂ becomes “11”, NAND circuit NAN ₁ or NAN ₂
The output of becomes “L”, and from then on the clock pulse is
It is not 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 the "DOWN" side. The up-down counter CO ₁ outputs a number equal to the number of slides subtracted, and the output of the up-down counter CO ₂ remains "00". In the opposite case, the up-down counter
The output of CO ₁ is “00” and the output of CO ₂ is “DOWN”
The number is calculated by subtracting the number of times the player slid to the "UP" side from the number of times he slid to the side. The outputs from the up-down counters CO ₁ and CO ₂ are output from a multiplexer circuit 64 composed of AND circuits AN ₅ , AN ₆ , AN ₇ , AN ₈ and OR circuits OR ₅ and OR ₆ , so that the counter output is “00”. ” is output. This output P ₂₂ and the output of the OR circuit OR _4
P20 is input to the display circuit 65, and displays the number of EVs to increase or decrease the amount of light received by flashlight emission for calculation. Furthermore, a binary number obtained by multiplying the output of the multiplexer circuit 64 by 10 is output from the decoder 66, and this output P ₁₀ and an OR circuit are output.
The output P ₂₀ of OR ₄ is the microcomputer 60
is input to the I/O port 67 of the . Note that the output of the OR circuit _OR4 is applied to the AND circuit _AN1 via an inverter _IN3 . Also,
Switch linked to reset button (not shown)
When S' ₂ is closed, an "H" signal is output for a certain period of time from the one-shot circuit OS ₅ , and this signal is applied to each reset terminal via the OR circuit OR ₇ , and is applied to the up-down counters CO ₁ and CO _{2 .} will be reset. Again, in FIG. 10, the switch _S3 is the aperture setting device 6 for switching between aperture priority and exposure time priority.
8 is the apex value AVs of the set aperture value.
A binary number multiplied by 10 is output. The exposure time setting device 69 outputs a binary number obtained by adding a constant _K5 to the set exposure time TVs and multiplying the sum by 10. The multiplexer 70 has the switch _S3 connected to the A terminal,
When the output P ₂₂ is "H", the data corresponding to 10 AVs from the aperture value setting device 68 is output to the terminal P ₁₂ , the switch S ₃ is connected to the T terminal, and the output P ₂₂ is "L". At that time, data corresponding to [10・(TVs+K ₅ )] from the exposure time setting device 69 is sent to terminal P _12.
Output to. The film sensitivity setting device 71 sets a value obtained by multiplying the apex value of the set film sensitivity by 10.
10・SV is output to terminal _P3 . The display device 72 is
The output _P14 from the above I/0 port 67 displays the appropriate aperture value or appropriate exposure time, and in the case of the aperture value, the integer part of the apex value is displayed by FNO.
The decimal part of the apex value is displayed in units of 0.1EV. For exposure time, the integer part of the apex value is displayed in hours and the decimal part is
Displayed as an abecs value in 0.1EV units. Furthermore, when overexposure occurs, "〓〓" is displayed, and when underexposure occurs, "〓〓" is displayed. The display device 73 displays the photometric output QVf by flash only or the appropriate aperture value AVf by flash only with the output P ₁₆ from the I/0 port 67,
In the case of the photometric output QVf, the apex value is displayed, and in the case of the appropriate aperture value AVf, the integer part is displayed by FNO and the decimal part is displayed by the apex value.
Furthermore, when the side light output from the flash is above a predetermined value, "〓〓" is displayed, and when it is below the predetermined value, "〓〓" is displayed.
The switch _S4 displays the display device 7 connected to the I/0 port 67 through the terminal _P24 .
This is for switching the display value of No. 3. When connected to the F terminal, the aperture value AVf is displayed, and when connected to the Q terminal, the photometry output QVf is displayed. The display device 74 displays the lighting contrast as an apex value using the output _P18 from the I/0 port 67, and the display device 75 displays the contrast between the flashed portion and the non-flashed portion or the flashed portion using the output _P20 . Displays the amount of flash contribution due to the apex value. Further, this display device 75 displays "〓〓" when the steady light hardly contributes to the exposure, and displays "〓〓" when the flash light hardly contributes to the exposure. The overexposure display device 76 includes, for example, two display elements, and when the A-D conversion value of the photometric output due to flash light overflows, one display element blinks at the output _P26 , and the A-D conversion value of the constant light When the converted value overflows, the other display element lights up at _P25 . The underexposure display device 77 includes, for example, two display elements, and when the A-D conversion value of the photometric output due to flash light is 0, one display element blinks at the output _P28 , and the When the D conversion value is 0, the other display element lights up with the output _P27 . The display device 78 displays the magnitude of the contribution of the flash light and the constant light to the exposure, and when the contribution of the constant light is greater, the display element lights up at the output _P30 . On the other hand, the CPU of the microcomputer 60 mentioned above
The section 80 includes an accumulator ACC composed of 8-bit registers and general-purpose working registers #0R to
Equipped with #5R, carry flag CY, and zero flag ZF. The CPU section 80 also includes a logic operation section, an address control section, an instruction control section, a timing controller, etc., but these are not directly related to the present invention, so their explanation will be omitted. In addition, general-purpose registers #0R to #5R are paired registers #0R, #1R; #2R, #3R; #4R,
It is also possible to connect #5R in series and use it as a 16-bit pair register #0PR to #4PR.
And the above I/0 port 67, CPU section 80,
Data is exchanged between a RAM 81 that temporarily stores data during the calculation process of the CPU section 80 and a ROM 82 that stores instructions and fixed data. Next, the operation of the embodiment shown in FIG. 10 will be explained with reference to the flowcharts shown in FIGS. 13 to 18. First, in FIG. 13, when the power is turned on, the terminal PUC becomes "H" for a certain period of time, and the microcomputer 60 is reset by a signal from the terminal PO of the timing controller 62 and starts operating. With this reset signal, both flags CY and ZF in the CPU section 80 are set to "0" and registers #0R~
#5R is all "00H", the contents of RAM 81 are all "00H", all outputs of I/0 port 67 are "0", and the operation starts from the instruction at the start address at step #0. In addition, the up/down counter shown in Figure 12 is activated by the signal from the terminal PUC.
CO ₁ and CO ₂ are also reset. Wait for the terminal _P10 to become "1" in step #1. That is, the switch S is turned on and waits for the flash to be emitted. When the switch S is turned on, the process moves to step #2 and counts the time T ₁ sec. T ₁ sec
is longer than the time required for all types of flash emitters to fully fire. Further, when the switch S is turned on, the timing controller 62
N-channel FET (FT ₂ ) with the signal from terminal γ ₁ of
is non-conducting, the signal from terminal γ ₂ is P channel
FET (FT ₁ ) is non-conducting, N-channel FET (FT ₃ )
becomes conductive, and the voltage generated only by the flash that has passed through the high-pass filter HPF is input to the integrating circuit 61.
A voltage QVf is generated across the capacitor _C3 , which is logarithmically compressed amount of light received due to flash light only. When the step #2 is completed, the terminal _P16 is set to "H" in the step # ₃ , and the A-D conversion circuit 4 starts the A-D conversion operation. Start counting. At the end of this time count, the A/D conversion operation has ended. Then, in step #5, set terminal _P16 to “L”,
Overflow terminal _P18 of A-D converter 4 is “H”
It is determined in step #6 whether or not it is. If there is an overflow, the process moves to step #7, where the terminal _P26 is set to "H" and the display element in the overexposure display device 76 is blinked. Next, #8
At step ₁ , the segment display “〓
〓” is output and displayed on the display device 73.As a specific method for this, for example, data at a specific address in the ROM 82 is set in register #4PR, and this register #4PR is used to
Specify the address of ROM82, and store the data necessary for display stored at this address in the accumulator.
ACC, and output the contents of this accumulator ACC to terminal _P16 . next,
Set "FF _H " to register #OR and address _M1 of RAM 81 and move to step #14. If the A-D conversion result does not overflow in step #6, the output of A-D converter 4 is determined in step #10.
Load P ₁ into register #OR. Furthermore, in step #11, it is determined whether the contents of register #OR are “OO _H ”, and if register #OR≠ _OOH , the process immediately moves to step #14, and if #OR=OOH, step #12 is determined. In step #13, terminal _P28 is set to "H" and the display element in the underexposure display device 77 flashes, "〓〓" is displayed on the display device 73 in step #13, and the process moves to step #14. . With each of the above steps, the acquisition of the digital value 10·QVf, which is 10 times the photometric output from the flash, is completed. To obtain a value that is 10 times the photometric output QVf, the circuit constants of the A-D converter 4 may be appropriately set. Next, in step #14, set terminal _P12 to “H”
Then, terminal γ ₂ becomes “L” and P channel
FET (FT ₁ ) conducts, N-channel FET (FT ₃ )
becomes non-conductive. With steps #15 and #16, connect the terminals.
Data 10・SV from P ₃ and 10・SV from terminal P ₁₂
Load data corresponding to AVs or 10/[TVs+K ₅ ] into registers #2R and #3R, respectively. Then, in step #17, set terminal _P16 to “H”,
Start A-D conversion at step #18.
A time count of T ₂ sec is performed, and when the count is completed, terminal P ₁₆ is set to "L" in step #19, and overflow terminal P ₁₈ is determined. Furthermore, in FIG. 14, when the terminal P18 is at "H" in step #20, the terminal _P25 is set at "H" in step #21, and the display element in the overexposure display device 76 is turned on. In step #22, "〓〓" is displayed on the display device 72, and in step #23, an "L" signal is output to terminal _P27 . This is because the terminal _P27 may be at "H" until the return command, which will be described later, and in this case,
This is to prevent both the outputs of the terminals P ₂₅ and P ₂₇ from becoming "H" and the display elements of the over-exposure display device 76 and the under-exposure display device 77 from lighting up. Next, in steps #24 and #26, it is determined whether the contents of register #OR, that is, [10・QVf], is over "FF _H " or 0 "00H", and in step #25, it is determined whether over or If it is 0, return to step #15. If [10·QVf] is neither 0 nor over, set "FF _H " in register #1R and jump to step #56. In step #20 above, overflow terminal _P18
When is “L”, move to step #29,
The output _P1 of the A-D converter circuit 4 is taken into the register #1R. This data corresponds to [10・(BVa+K ₅ )], and in step #30, it is determined whether this data is 0 or not. If it is 0, the terminal is set in step #31.
Output the "L" signal to _P25 , set the terminal _P27 to "H" in step #32, and output the underexposure display device 77.
lights up the display element. Next, in steps #33 and #34, the contents of register #OR [10.
QVf] is over or 0, and if it is over or 0, in step #35, "〓〓" is displayed on the display device 72, and the process returns to step #15. Therefore, take action. Also, if [10・QVf] is neither over nor 0, jump to step #56. If the contents of register #1R are not 0 in step #30 above, proceed to step #37.
Outputs "L" signals to terminals P ₂₅ and P ₂₇ . Similar to steps #23 and #31, step #37 is used when the signals at terminals P ₂₅ and P ₂₇ have become "H" and the display element is lit during the previous operation process. It is provided to turn off the light. Next, in steps #38 and #39, it is determined whether the contents of the register #OR [10·QVf] are over or 0, and if it is neither, the process jumps to step #56. If [10・QVf] is over or 0, #40
Proceeding to step #1R, the contents of register #1R and the contents of register #2R are added, and the added contents are taken into register #1R. This is [10・(BVa
+ _K5 )+10.SV=10・(EVa+ _K5 )].
Next, in step #41, [10・(EVa+K ₅ )−
10・(TVs+K ₅ )=10・AVs].
Next, in step #42, it is determined whether the output of terminal _P22 is an "H" signal, and if it is an "H" signal, switch _S3 is connected to terminal A, and the aperture value is
AVs has been set, and the value found in step #41 corresponds to [10·(TVs+K ₅ )]. In step #43, it is determined whether this value is greater than the shortest exposure time [10·(TVmax+K ₅ )]. If it is, the process moves to step #47 and "〓〓" is displayed on the display device 72. Display it in
In step #48, data at address _M1 of RAM 81 is transferred to register #OR, and in step #49, the process returns to step #15. In the steps described so far, the data at address _M1 is either over or 0 due to step #9'. In step #43 above, the contents of register 1R are set to [10.
(TVmax+K ₅ )] In the following cases, next check whether the carry flag CY is set to 1, that is,
Determine whether the operation result of step #41 is negative, and if it is negative, take the contents of address _M1 of RAM 81 into register #OR, jump to step #35 at step #55, At step #35, "〓〓" is displayed on the display device 72, and at step #36, the process moves to step #15. Also,
When the carry flag CY is 0 in step #44, the data corresponding to the calculated TVa is displayed on the display device 72, and in step #46, the process moves to step #49 via step #48, and then the process proceeds to step #49. Return to step 15. Here, the display method in step #45 is to divide the contents of register #1R by 10,
Specify the ROM 82 address corresponding to the quotient data, that is, the integer part of the apex value, and transfer the time display data stored there to the accumulator.
Move to ACC. This transferred data is output to terminal _P14 , and the remainder of the division, that is, the data corresponding to the decimal part of the apex value, is used to specify the same address in ROM 82, and the segment display of the apex value stored there is performed. The necessary data is also output to _P14 and the decimal part is displayed. In step #42 above, when the output _P22 is “L”, the calculated value corresponds to [10・AVa],
In this case as well, at step #50, [10・AVmax]
In step #51, the carry flag CY is determined, and in step #52, the display device 72 displays "〓〓" or "〓〓" or FNO and the decimal part. At step #53,
After going through step #48, move on to step #49,
Return to step #15. Here, in step #52, as in step #45, the integer part data is converted to FNO display via ROM 82, and the decimal part is also displayed as an apex value via ROM 82. In Figure 15, step #56 includes:
The transition starts from steps #27, #34, and #39. At this point, the contents of register #0R are 10.
QVf is neither over nor 0. At step #56, the data from terminal _P10 , that is, the switching amount of flash light emission amount [10·Δf] is taken into register #4R. Next, in step #57, the contents 10 and QVf of register #0R are moved to address _M1 of RAM81, and in step #58, terminal _P20 is set to either "H" or "L".
Determine whether it is a signal. Here, the "H" signal means that the amount of light emitted corresponding to the data from terminal _P10 is reduced, and in step #59, [10・QVf−10・Δf=10・QVf′] Perform the calculation of
Load this result into register #0R. next,
At steps #60 and #61, carry flag
Determine whether CY or zero flag ZF is 1, that is, whether the operation result in step #59 is negative or 0. If it is negative or 0, in step #62, 〓”
is displayed on the display device 73, and in step #63,
Outputs “L” signal to terminal _P30 . This step #63 has the same meaning as each step #23, #31, and #37, and before step #63, the display element in the display device 78 that displays the magnitude of the steady light and flash light lights up. Therefore, it is necessary to turn off the display element at the time of step #63. Next, in step #64, determine whether the contents of register #1R [10・(BVa+K ₅ )] are 0 or not.
At step #67, if it is 0, "〓〓" is displayed on the display device 72, and at step #68, the process moves to step #48.
The data corresponding to 10・QVf stored at _address M1 of 1 is taken into register #OR, and in step #49, the process returns to step #15. If [10・(BVa+K ₅ )] is not 0 at step #64, then register #1R is set at step #65.
It is determined whether the content of is over or not, and if it is over, proceed to step #48 at step #68,
In this step #48, data corresponding to 10・QVf stored in RAM81 is transferred to register #0R.
and return to step #15. At step #65, if the contents of register #1R are not over, the process returns to step #40, and through steps #41 to #49, the aperture value or exposure time is determined by performing the above-mentioned calculation using the ambient light. , or “〓
〓”, “〓〓” are displayed on the display device 72 and the RAM 8
Move the data corresponding to 10・QVf stored at _address M1 of 1 to register #0R and return to step #15. On the other hand, if the signal at terminal _P20 is "L" at step #58, the process moves to step #69,
QVf + 10・Δf=10・QVf′], this data is loaded into register #0R, and in step #70, this data is calculated as [10・QVfmax], that is, the fixed data corresponding to the maximum value of QVf. Determine whether it is large. As a result of this determination, if it is large, an "L" signal is output to terminal P ₃₀ in step #71, and a signal of "L" is output to terminal P 30 in step #72.
After displaying "〓〓" in step #73, return to step #64 described above, and then display "〓〓" or "〓〓" on the display device 72 described above, or display the appropriate aperture using only constant light. Each step displays a value or proper exposure time. After this, RAM
Set the data corresponding to [10・QVf] stored in 81 to register #0R, and then set it to #36 or #49.
Return to step #15 at step #15. that's all,
For step operations #53 to #73, change [10・QVf] to Δf
[10・QVf′] becomes 0 by changing
This corresponds to the operation when the value becomes larger than [10・QVfmax]. In steps #61 and #40 above,
[10・QVf′] is greater than 0, [10・QVfmax]
If it is determined that the value is smaller than , move to step #74, and register #0R
Set the contents [10・QVf'] to address _M2 of RAM81. Next, in step #75, [10.
QVf′+10・SV=10・AVf],
This data is loaded into the register #0R, and in step #76, it is determined whether the terminal _P24 is an "H" signal or a "L" signal, that is, whether the switch _S4 is connected to the F terminal or whether it is connected to the Q terminal. Determine if it is connected. When connected to the F terminal, the decimal part of the FN0 and apex value corresponding to AVf is displayed on the display device 73 in step #78, and when connected to the Q terminal, in step #77, QVf′ to 0.1EV
Display as an apex value in units. Next, in step #79, it is determined whether the contents of register #1R are 0, and if it is 0, in step #81,
Display the FN0 corresponding to AVf and the decimal part as an apex value on the display device 72, and connect the terminal in step #82.
Output an "L" signal to _P30 , and proceed to step #48 at step #83. And RAM81
Load the data corresponding to [10・QVf] stored in register #0R, and in step #49,
Return to step #15. Also, register #1R
If the contents of register #1R are not 0, determine whether the contents of register #1R are over in step #80,
If it is over, step operations from #82 onwards are performed in the same way as described above. At step #80, if the contents of register #1R are not over, move to step #84 and transfer the contents of register #1R [10・(BVa+K ₅ )] to RAM 8.
Moved to 1-M ₃ . Next, in step #85, [10・(BVa+K ₅ )+10・SV=10・(BVa+
K ₅ )], step #86, [10・(EVa+K ₅ )−
10・(TVs+K ₅ )=10・AVa] or [10・
(EVa+K ₅ )-10·AVs=10·(TVa+K ₅ )], and in step #87, it is determined whether the terminal _P22 is an "H" signal or an "L" signal. terminal
When the P ₂₂ signal is “H”, aperture priority is given, so #89
When the signal at terminal _P22 is "L", priority is given to the exposure time, so the process moves to step #131. In step #89 above, it is determined whether the contents of register #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 the when,
At step #90, an "L" signal is output to terminal _P30 , and at step #91, the process moves to step #47. In step #47, “〓” is displayed on the display device 72.
〓” is displayed, and in step #48, RAM81
The data corresponding to [10・QVf] stored at address _M1 of is loaded into register #0R, and at step #49, the process returns to step #15. 〔Ten·
If (TVa+K ₅ )] is smaller than [10・(TVmax+K ₅ )], continue with step #92,
It is determined whether [10・(TVa+K ₅ )] has become negative, and if it is negative, that is, when the carry flag CY is 1, the terminal P ₃₀ is set to “L” in step #93.
according to the signal. Then, at step #94, #54
The program moves to step #55, moves to step #35, and displays "〓〓" on the display device 72. Display it, go to step #36, and go back 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・(TVa+K 5 )] using only the flash.
AVf] and the set aperture value [10・AVs], and if the data corresponding to [10・AVf] is greater than the data corresponding to [10・AVs], overexposure occurs. Therefore, at step #96, move to step #90 and set "L" to terminal _P30 .
After outputting the signal, proceed to step #47 at step #91, display "〓〓" on the display device 72,
At step #48, it is stored in address _M1 of RAM81. Set [10・QVf] to register #0R and return to step #15 at step #49. In step #95 above, if the data corresponding to [10・AVf] is smaller than the data corresponding to [10・AVs], in step #97, the data corresponding to [10・AVs] is
−10・AVf=10・Δ3] and import this data into register #3R. Continuing,
At step #98, set the constant _K6 to register #2R, and at step #99, set the data stored at the address in ROM82 specified by the contents of 16-bit register #2PR to register #0R. do.
The data set in this register #0R is data corresponding to [-10·log2 (1-2 ^- 〓 ³ )] stored in advance in the ROM 82 according to Table 1 above. That is, K ₆ + of ROM82
At address 10· _Δ3 , data corresponding to [−10·log2 (1−2 ⁻ 〓 ³ )] is stored. At step #100, the contents of this register #0R and the contents of register #1R [10・(TVa+K ₅ )] are added,
[10・(TVa+K ₅ )−10・log2(1−2 ^- 〓 ³ )=10・
(TVx+K ₅ )] is performed, and this data is taken into register #0R. Continued, #101
In step 1, the data corresponding to [10・(TVx+K ₅ )] is changed to the data corresponding to the shortest exposure time.
(TVmax + K ₅ )], and if it is, go to step #102 and perform the steps from #90 onwards.
Return to step #15. If the data corresponding to [10・(TVx+K ₅ )] is less than the data corresponding to [10・(TVmax+K ₅ )], in step #103,
The exposure time TVx and the decimal part of the apex value are displayed on the display device 72. Continuing, in step #104, [10・(BVa+K ₅ )] stored at address _M3 of RAM81 is stored in register #1R, and in step #105, 10 stored at address _M2 of RAM81 is stored. - Load QVf′ into register #2R.
Then, in step #106, set the data corresponding to [10・SV] from terminal P ₃ in register #3R, perform the calculation [10・QVf′+10・SV=10・AVf], and In step #107, data corresponding to this calculation is set in register #4R, and then based on the calculated appropriate exposure time,
In step #108, set the appropriate aperture value for steady light only at this exposure time [10・AVa=10・(BVa+
K ₅ )+10・SV−10・(TVx+K ₅ )] and import it into register #5R. In steps #109 and #110, the calculation result in step #108 is 0.
It is determined whether or not the value is below, and when it becomes 0 or less, that is, when the carry flag CY or zero flag ZF is 1, in step #111,
Outputs an “L” signal to terminal _P30 . and,
At step #112, QVf' is displayed as an apex value as a lighting contrast on the display device 74, and at step #113, the process moves to step #54 where the QVf' is displayed at address _M1 of the RAM 81 [10. QVf] is taken into register #0R, the step operations from #35 onwards are carried out, and the process returns to step #15. If it is determined in steps #109 and #110 that the operation result is not less than 0, the process moves to step #114, where the contents of register #4R and register #5R,
That is, the magnitude of the data corresponding to 10·AVa and 10·AVf is compared. Here, [10・
AVf10・AVa], in step #115, output an “L” signal to terminal _P30 , and in step #116, perform the calculation of [10・AVf−10AVa=10・1Δ51] and store the register. #1 Import into R. In step #114, if [10・AVf＜10・AVa],
In step #117, set terminal _P30 to "H" to display that steady light has a greater contribution to exposure than flash light, and in step #118, set [10.
AVa−10・AVf=10・1Δ51] and set this data in register #1R. next,
At step #119, data corresponding to the writing contrast, which is the content of register #1R, is displayed on the display device 74 as an apex value. Next, at step #120, go to [10・
Determine the size of the data corresponding to [AVf] and [10・AVa], and if it is [AVfAVs], use step #121 to determine [10・(AVa+3.9−AVf)=
10・(3.9−1Δ51)], and when [AVa＞AVf], use step #122 to calculate [10・(AVf+3.9−AVa)=
10・(3.9+1Δ51)] and import them into each register #3R. As is clear from the explanation in Table 2, when Δ51 is smaller than -3.9,
[log2(1+2〓 ⁵ )] becomes 0 if 0.1 is the minimum unit, so [3.9×10=27H] is added. vice versa,
When [AVf>AVa], [10・AVa+3.9−AVf]
=10・(3.9+1Δ51)] and set this data to register #3R. Then, in step #123, if the operation result is not negative, that is, if the carry flag CY is 0, then in step #128, set the constant _K7 to register #2R,
In step #129, the address of the ROM82 is specified with register #2PR, and the data stored there [10·log2(1+ ^2〓5 )]=Δ6 is taken into register #0R. Next, in step #130, this data is displayed as an apex value on the display device 75, and
At step #127, move to step #54,
Stored at address _M1 of RAM81 [10.
QVf] is taken into register #0R, step operations from #55 onwards are carried out, and the process returns to step #15. Also, when the calculation result of step #121 is negative, that is, the carry flag
When CY is 1, in step #124, [10.
AVs] and [10・AVf], and when [AVs>AVf], #126
At step , "〓〓" is displayed on the display device 75. Next, when [AVs<AVf], in step #125, “〓〓” is displayed on the display device 75,
At step #127, move to step #54,
Stored at address _M1 of RAM81 [10.
QVf] is taken into register #0R, step operations from #55 onwards are carried out, and the process returns to step #15. The above steps from #120 onwards correspond to steps for displaying the contrast between the portions irradiated with the flash light and the portions 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 ROM82 is calculated by subtracting the larger one from the smaller one of AVa and AVf, and adding 3.9 to this value so that Δ5 is always negative. is specified and stored there [log2(1+ ^2〓5 )]
It is designed to display data corresponding to. When the above Δ5 is smaller than −3.9, that is,
When [Δ5+3.9] is less than 0, [log2(1+2〓 ⁵ )]
becomes smaller than 0.1, and at this time, [AVf>
AVa], “〓〓” is displayed to indicate that the ambient light does not contribute to exposure, and in the case of [AVa > AVf], flash light does not contribute to exposure, so the contrast is “0”. 〓〓” is displayed. When terminal _P22 is “L” in step #87,
At step #88, jump to step #131. In this case, the exposure time TVs is set. In step #131, it is determined whether the contents of register #2R are larger than the data 10・AVmax corresponding to the minimum aperture value AVmax, and if so, in step #132, the process moves to step #90 and the terminal is Output “L” signal to P ₃₀ ,
At step #91, move on to step #47. #47
In the step, “〓〓” is displayed on the display device 72, and
At step #48, the data corresponding to [10.QVf] stored at address _M1 of RAM 81 is loaded into register #0R, and at step #49, the process returns to step #15. If the calculation result in step #86 above is less than 0, display QVf' as an apex value on the display device 74, set [10・QVf] in register 0R, and then return to step #15. . The calculation result of step #86 is [0<10・
When AVa<10・AVmax], in step #136, determine the magnitude of AVf and AVa, and set [AVf
AVa], use step #137 to connect terminal P _30.
Output the “L” signal to and step #138.
Calculate [10・AVf−10・AVa=10・1Δ51], and in step #139, when AVa>AVf, set terminal _P30 to “H” to show that the effect of the constant light is large, and Writing in 140 steps
Calculate contrast Δ5. And #141
Lighting Contrast Δ5
is displayed on the display device 74 as an apex value. This completes the lighting contrast display. In step #142, determine the magnitude of AVf and AVa again, and if [AVf > AVa], in step #143, [10・(AVa+3.9)−10・AVf=10・
(3.9−｜Δ5｜)], #144 when [AVf<AVa]
At the step of [10・(AVf+3.9)−10・AVa=
10・(3.9+｜∆5｜)]. When the result of this calculation is less than 0, that is, when the carry flag CY is 1, in step #146, similar to steps #124 and below, the magnitude of AVa and AVf is determined, and [AVf>AVa] is determined. when,
At step #147, change “〓〓” to [AVa>AVf]
In this case, "〓〓" is displayed on the display device 75 in step #148. Then, after similar steps, return to step #15. Also, if the calculation result in step #144 is greater than 0,
Similar to the steps following #128, in step #146, set the constant _K7 to register #4R, and in step #147, specify the address of ROM82 in register #4PR, and write the information stored there. Data 10・log2
Load (1+2〓 ⁵ ) into register #2R. next,
In step #130, this data is displayed as an apex value on the display device 75. Next, in step #150, the magnitude of AVa and AVf is determined, and in step #151 or #152, the larger value is displayed. is added to the above [10・log2(1+ ^2〓5 )]. Therefore, [10・AVa+10・log2(1+2〓 ⁵ )=10・
AVx] or [10・AVf+10log2(1+2〓 ⁵ )=
10・AVx] is found. Next, in step #153, it is determined whether this calculation result is larger than [10·AVmax], and if it is larger than [10·AVmax], “〓〓” is displayed on the display device 72 in step #47. Display and step #48, RAM81
Set the data corresponding to [10・QVf] stored at address _M1 in register #0R, and return to step #15. Also, if it is less than [10・AVmax], in step #155, the decimal part of the FN0 and apex value corresponding to [AVx] is displayed on the display device.
2, and in step #48, _M1 of RAM81
Load the data corresponding to [10・QVf] stored at address into register #0R and return to step #15. In the above explanation, we return to step #15 because when the constant light BVa changes or the set values (TVs, AVs, SV, Δf) change, the displayed values also need to change. Therefore, after the display is completed, it is necessary to take in the various data mentioned above and perform calculations again. When the measurement person presses the photometry button again, the switch S is turned off, and the reset signal from the terminal _P0 of the timing controller 62 detailed in FIG. 11 is output, and the microcomputer 60
is reset, and except for the display circuit 65 of Δf,
All displays disappear. And P channel
The FET (FT ₁ ) and the N-channel FET (FT ₂ ) become conductive, and the N-channel FET (FT ₃ ) becomes non-conductive, returning to the state at power-on. Figure 19 shows the lighting contrast Δ5
is set, the appropriate exposure time TVx, the appropriate aperture value AVx, the apex value QVt of the overall light intensity during flash photography, the contrast between the areas illuminated by the flash and the areas not illuminated by the flash, or the brightness of the subject due to the illumination of the flash. This is another embodiment of the arithmetic circuit 10 that calculates the amount (number of stages) Δ6. In this embodiment, from the setting device 90,
A signal indicating the positive or negative of the set lighting contrast Δ5 is sent from the terminal 90a, and the absolute value |Δ5| of the lighting contrast is sent from the terminal 90a.
It is output from b. Then, in the addition/subtraction circuit 91, according to the signal from the terminal 90a,
BVa+｜Δ5｜ when Δ50, when Δ5<0
Perform the calculation of BVa−Δ5. Furthermore, the subtraction circuit 9
2, the following calculation is performed: BVa+Δ5−QVf′=TVx (13−1). This corresponds to a modification of the above equation (13), and therefore, the appropriate exposure time TVx
is obtained. On the other hand, when an address is designated by data corresponding to the writing contrast Δ5 from the setting device 90, data log2 (2 ^- 〓 ⁵ +1) fixedly stored at that address is read from the ROM 93.
This read data and the data QVf' from the subtraction circuit 15 are input to the addition circuit 94, and the following calculation is performed: QVf'+log2(2 ^{- 5} +1)=QVt (18). Here, the reason why the apex value QVt of the total light amount is determined by the above equation (18) is that based on the above equation (14) to the above equation (13), BVa−TVx is eliminated and the logarithm of both sides is calculated. This is because by taking , the above equation (18) is obtained. In the subtraction circuit 95, the calculation BVa-TVx is performed, and further in the subtraction circuit 96, the calculation QVt-(BVa-TVx)=Δ6 (15) is performed. Furthermore, in the adder circuit 97, the calculation QVt+SV=AVx (19) is performed to calculate the appropriate aperture value AVx,
These calculated data are displayed on the display device 27. As described above, according to this embodiment, the light emission amount QVt of the flash light emitted in advance, the constant light BVa,
If the film sensitivity SV is different and the measurer sets the desired lighting contrast Δ5,
Appropriate exposure time TVx, aperture value AVx, apex value QVt of overall light intensity, contrast between areas illuminated by flash and areas not illuminated, or amount (number of steps) Δ6 of brightening of the subject due to illumination of flash are automatically determined. can get. Figure 20 shows the appropriate exposure time TVx and aperture value when the contrast between the areas illuminated by the flash and the areas not illuminated by the flash, or the amount of brightness (number of steps) Δ6 of the subject due to the illumination of the flash, is set.
This is an embodiment of a calculation circuit 10 that calculates AVx, lighting contrast Δ5, and total light amount QVt. When an address in the ROM 99 is specified with data Δ6 from the setting device 98, a signal indicating the positive or negative of the data is sent from the terminal 99a, and |log2(2〓 ⁶ −
1) Data of | is read. This read data is used for writing for the reasons shown below.
Corresponds to contrast Δ5. In other words, if we eliminate QVt from 2QV′f+2BVa−TVx=2QVt…(14) and Δ6=QVt−(BVa−TVx)…(15) and take the logarithm of both sides of equation (14), we get QV′f −(BVa−TVx) = log2(2〓 ⁶ −1) …(20) is obtained. Therefore, from the above equation (13), log2( ^2〓6-1 )=Δ5...(20-1) holds true. Then, as in the embodiment shown in FIG. 19, the addition/subtraction circuit 91 and the subtraction circuit 92 perform the calculation TVx=BVa+Δ5−QV'f (13-1). Additionally, an addition circuit 100 and an addition/subtraction circuit 101
Then, the following calculation is performed: QV′f+Δ6−Δ5 =QV′f+QVt−(BVa−TVx) −{QV′f−(BVa−TVx)}=QVt...(21)
QVt is calculated, and further, the addition circuit 97 performs the following calculation: QVt+SV=AVx (19). In this case as well, each calculated data is sent to the display device 27 as in the embodiment of FIG. As described above, according to this embodiment, the light emission amount QVf of the flash light emitted in advance, the constant light BVa,
If the film sensitivity SV is varied, and the measurer sets the contrast between the flashed and non-flashed areas, or the amount (number of steps) by which the subject becomes brighter when the flash is irradiated, Δ6 can be set. , appropriate exposure time TVx, aperture value
AVx, total light intensity apex value QVt, and lighting contrast Δ5 can be automatically obtained. As described above, according to the present invention, when the aperture value is set, an appropriate exposure time can be obtained that takes into account the constant light during flash photography, and furthermore, the set aperture value and film sensitivity can be changed. To easily and accurately obtain a new appropriate exposure time without having to fire the flash again and re-measure the light even when the flash light emission amount is switched, or when the brightness of the constant light changes. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the principle of the invention, Fig. 2 is a block circuit diagram showing an embodiment for obtaining the light quantity QV'f of flash only, and Figs. 2 is a block circuit diagram showing another embodiment of the circuit for determining the amount of light of flash only; FIG. 6 is a block circuit diagram showing the configuration of an embodiment of the present invention;
FIG. 7 is a block circuit diagram showing another embodiment of the present invention, FIGS. 8 and 9 are circuit diagrams showing other embodiments of the configuration of the photometric section according to the present invention, and FIG. 11 is a detailed circuit diagram of the timing controller in FIG. 10; FIG. 12 is a circuit diagram of the signal output circuit in FIG. 10; FIGS. 1
Figures 5, 16, 17, and 18 are
A flowchart showing the operation of the embodiment shown in the figure,
FIGS. 19 and 20 are block circuit diagrams showing other embodiments of the photometric device according to the present invention. 1... Strobe device, 2... Timing controller, 3... Photometry circuit, 4... A-D converter,
6, 7...Register, 10...Arithmetic circuit, 60...
...Microcomputer, Ps...flash, Pa...
Ambient light, TVx...appropriate exposure time.

Claims (1)

[Scope of Claims] 1. Photometering means for performing photometry on a subject irradiated with light including a flash emitted in advance and obtaining a photometric value corresponding to the amount of flash light received in relation to the amount of flash light emitted, and the influence of the flash light. a means for outputting a signal corresponding to information on the intensity of only the stationary light based on photometry of only the stationary light that is not affected; a calculation means for calculating information on the amount of received light based only on the steady light within the set exposure time; and setting a predetermined conversion value corresponding to a change in the amount of received flash light for the photometric value obtained by the photometry means. and display means for displaying information corresponding to the ratio of the total amount of light received within the set exposure time to the amount of light received based only on the steady light based on the calculation result of the calculation means, the photometric value, and the converted value. A photometric device for flash photography, characterized in that: 2. A photometric means for performing photometry on a subject irradiated with light including flash light emitted in advance and obtaining data corresponding to the amount of flash light received; means for outputting a signal corresponding to the information on the intensity of only the light; and a means for outputting a signal corresponding to the information on the intensity of only the light, and a means for calculating the amount of light received based only on the steady light within the set exposure time according to the signal corresponding to the information on the intensity of the steady light only and the set exposure time. a calculation means for calculating information, and when the difference between the information on the amount of received light based only on steady light and the data corresponding to the amount of received flash light within the set exposure time is greater than a predetermined value and the data corresponding to the amount of received flash light is large; 1. A photometric device for flash photography, comprising: display means for displaying information. 3. A first circuit that performs photometry on a subject irradiated with light including flash light emitted in advance and obtains a first signal corresponding to the amount of flash light received, and a first circuit based on photometry of only steady light that is not affected by flash light. The second one corresponds to the information on the intensity of only the steady light of the lever.
a second circuit for obtaining a signal, an aperture value setting device for setting an aperture value, a film sensitivity setting device for setting film sensitivity, the first circuit, the second circuit, the aperture value setting device, and the film sensitivity setting device. 1. A photometry device for flash photography, comprising: an arithmetic circuit that calculates an appropriate exposure time during flash photography based on each signal from the device. 4. For flash photography according to claim 3, wherein each signal from the first circuit, the second circuit, the aperture value setting device, and the film sensitivity setting device corresponds to an apex value. Photometric device. 5. For flash photography according to claim 3 or 4, wherein the first circuit comprises a high-pass filter connected to the photometric means and an integrating circuit connected to the high-pass filter. Photometric device. 6. Flash photography according to claim 3 or 4, wherein the first circuit includes an integrating circuit that integrates the output signal from the photometric means for a predetermined time during flash emission. photometric device. 7. Claims 4 and 5, characterized in that the second circuit includes a third circuit that obtains a signal corresponding to the intensity of only the stationary light from the photometric means.
6. The photometry device for flash photography according to item 6. 8. Claims 3, 4, and 8, wherein the second circuit includes an integrating circuit that integrates the intensity signal of only the stationary light from the photometric means for a predetermined time. The photometry device for flash photography according to item 5, item 6, or item 7. 9. Claims 3, 4, or 5, characterized in that the second circuit includes an integrating circuit that integrates the signal from the photometric means for a predetermined period of time during flash emission. Photometer for flash photography. 10 A patent claim comprising a conversion amount setting device and a changing circuit that changes the signal corresponding to the appropriate exposure time from the arithmetic circuit by an amount corresponding to the signal from the conversion amount setting device. Range of 3rd term, 4th term, 5th term, 6th term, 7th term,
The photometry device for flash photography according to item 8 or 9. 11. Claims 4 and 5 further include a timing control circuit that inputs a new signal to the arithmetic circuit and causes the arithmetic circuit to operate again every time the arithmetic circuit finishes its calculation. A photometric device for flash photography according to item 5, item 6, item 7, item 8, item 9, or item 10.