JPS5814824A - Photometric device for photographing by use of auxiliary light - Google Patents

Abstract

PURPOSE:To take a photograph under the quantitative control over the contrast by providing 2 or more photodetectors for executing photometry on the plural parts of a photographing picture, and controlling the contrast of the photometric parts to attain a prescribed value from the photodetecting quantities at the time of light emission and non-light emission of an auxiliary light source. CONSTITUTION:Photodetectors PD1, PD2 execute photometry of different parts on the respective photographing pictures. A light emitting part FL1 for spare light emission receives a closing signal of a switch (S) 6 of a camera side and emits a flash. When the S 6 is closed, the light emitting part FL1 starts light emission, also a timer TI1 is operated, output currents of the elements PD1, PD2 are integrated by capacitors C11, 12, and the integration is stopped after a constant interval of time. Voltage in case of said light emission and non-light emission is A/D-converted 8 through a multiplexer 7, and is applied to a demultiplexer 9. To a block 14, a block 26 and a block 73, Tvc of said reset time, Tvs of an exposure time and a contrast data DELTA cs are provided, respectively, and the quantity of light between photometric parts by a main light emitting part FL2 can be controlled to a prescribed ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an apparatus for photographing by emitting light from a flash light source (hereinafter referred to as "auxiliary light source") in constant light.

BACKGROUND OF THE INVENTION Generally, an auxiliary light source is used in ambient light in order to adjust the contrast between different parts of a photographic screen to a desired value. For example, when the main subject is dark compared to the background due to backlighting, etc., an auxiliary light source is used to increase the brightness of the main subject to achieve a desired contrast with the background.

However, no photometry device has yet been proposed that is suitable for adjusting the contrast between various parts of the photographic screen as desired by the photographer using an auxiliary light source. conventionally,
Photographers with a wealth of experience in photography used to adjust the lighting based on their experience to obtain the shots they desired; however, this was only a qualitative control of contrast; There was no specific control. Furthermore, it is extremely difficult for a typical photographer to even qualitatively control the contrast.

SUMMARY OF THE INVENTION An object of the present invention is to propose a novel photometric device suitable for photographing with an auxiliary light source to obtain the contrast between each part of a photographic screen as desired by the photographer.

The feature of this invention is that at least two light receiving elements are provided to measure the light of a plurality of parts of the shooting screen, and a signal corresponding to the amount of light received by each light receiving element when the auxiliary light source is emitting light and a signal corresponding to the amount of light received by each light receiving element when the auxiliary light source is not emitting light is provided. two types of signals corresponding to the amount of light received by each of the light receiving elements are obtained, and based on these two types of signals, the contrast necessary to bring the contrast between the photometric portions of at least two light receiving elements to a predetermined value is determined. first to control
The value of the factor is calculated.

Therefore, by using the photometric device according to the present invention, it becomes possible to perform photography with quantitative contrast control, which was previously impossible.

EXAMPLES Hereinafter, the present invention will be explained in detail along with examples shown in the drawings.

First, the basic idea of this invention is to control the contrast in the photographic screen using an auxiliary light source such as a flashlight emitting device. 2 each. 2, and the light emission Qvfmt of the auxiliary light source from the two parts during measurement is
The amount of light reflected by Qvfm2 is 2. 2. If the exposure time is T 2 VS, the contrast of the two parts is set to the desired Δ. To control to , (2B■1-TvS+2qvfm1+△fx)/(2B
V2-TVS+2 Q V f m 2+△fX):2
△cs90010. Δfx that satisfies (1-2) is determined, and the amount of light emitted by the auxiliary light during photographing is compared with the amount of light emitted during measurement, and the amount of light emitted is changed by zAfx. Then, the contrast between the two parts reproduced on the photoreceptor will be △c5
It is said that it is controlled by.

FIG. 1 is a block diagram showing one embodiment of the present invention.

Note that a signal line with diagonal lines indicates a multi-bit digital signal (or signal line).

(PD+) and (PD2) are light-receiving elements that measure different parts of the shooting screen, respectively; (D+) and (D2)
) is a logarithmic compression diode, (OA+ ), (OA
2) is an operational amplifier (BTn).

(Br12) is a logarithmic expansion transistor, (Br21)
, (Br22) are current mirror transistors.

Diode (Dll), (D21) and capacitor (C,
+1), diodes (D12), (D22), and a capacitor (C12) is a known logarithmic compression integration circuit.

(FL) is a flashlight emitting device for auxiliary light, (FLI)
is a light emitting part for preliminary light emission. This light emitting part for preliminary light emission (
FLY) receives a closing signal from the switch (S6) on the camera side via terminals U32) and (I31) and emits a flash. A switch (S6) on the camera side is closed in response to depression of a photometry button (not shown) or a release signal (not shown). (FL2) is a light emitting part for main light emission. This main light emitting section (FL2) is connected to the switch (S5) on the camera side.
) closing signal to the terminal (I12).

(j++) and emits a flash. This camera-side switch (S5) is a synchro switch that closes when the shutter (not shown) is fully open. Main light emitting part (FL2)
The light emission amount of △f
The number is increased by x. This △fx is the terminal (ja2),
(ja+), but △Ex≧0
Therefore, the amount of light emitted by the preliminary light emitting section (FLY) corresponds to the minimum amount of light emitted by the main light emitting section (FL2).

When the switch (S6) is closed, the preliminary light emitting section (FLY)
starts emitting light, the timer (Tl 1) operates, the switches (ASl) and (AS2) are connected to the terminals (FJ) and (F2), and the switch (AS3)
), (AS4) are released. Therefore, the capacitor (
At (, +t) and (C12), the currents from the transistors (Br31) and (Br32) corresponding to the output currents of the light receiving elements (PDl) and (PD2) during preliminary light emission are logarithmically compressed and integrated. The timer (TII) activates the switch (AS) after a certain period of time (2c seconds) after the preliminary Tv light starts.
+), (AS2) to terminals (AI), (A2),
Stops integration into capacitors (Ctl) and (CI2).

Therefore, at this time, the capacitor (C1t), (C
The integrated voltage of 12) is Qv + :1 og 2 (2BV l −TV C
QV ""1),,,,,00. (4-1)+2 Qv2= l o g 2 (2BV 2-”%’ C
+2Qvfn12 ), . . . , (4-2), and this voltage is held.

Next, from the multiplexer (7), a capacitor (CI
+), terminal (AI), capacitor (CI2), terminal (A
The analog signals from 2) are sequentially input to the A-D converter (8), and the A-D converted data is sequentially passed through the demultiplexer (9) to registers Q, α, (2), and a.
'3. A capacitor (Ca
The data Qv1 corresponding to the output of the capacitor (C12) is stored in the register aυ, and the data QV2 corresponding to the output of the capacitor (C12) is stored in the register aυ.
However, data Bv1 corresponding to the signal from the terminal (A1) is set in the register (to), and data B2 corresponding to the signal from the terminal (A2) is set in the register 03, respectively. When the data setting to registers GO~04 is completed, the switch (A) is activated by the output of the timer circuit (TI).
Sa), (AS4) are closed, and the capacitor (Cat)
, (CI2) are discharged and prepared for the next photometry.

First, calculations using blocks indicated by 00 to @ will be explained. In the subtraction circuits QI2 and Ql, the apex value Tvc of the integration time from block α→ and the register (121, Q
Input data BV1+BV2 from l, (Bv+
Tvc) and (BV2 TVC) are calculated. Subsequently, subtraction circuit Q71. In Q81, Qvl-(Bvl-Tvc)=△ss-・-(
5-1) QV2-(BV2-Tvc)=△12 ・-
-(5-2), calculate △11+△12, and ROMa*, m is the data from the subtraction circuit aη, (to) log2(2△11 1), l0g2(2△
121). Addition circuit eA)
, @, Qvfmt=(BvITvc)+log2(2△”-1
)・(6-1)Qvfm2=(Bv2”vc)+10g
2(2△”-1)・(6-2) is performed to calculate the amount of light reflected by flash light emission during preliminary light emission Qv fm+ , Qv
Calculate fm2. Addition circuit■υ.

The reason why the amount of reflected light Qvfm is derived from @ is 2Qv
= 2”v-Tvc Qvfm, , 1, 8.0.
This is because when Qv is eliminated from equations (4,)2 and (5), Qy fmBv -Tv c (2Δ-1)-2 is obtained, and equation (6) is obtained by taking log2 on both sides.

Next, using blocks (301) to (309), (1-
2) The calculation for calculating the data Δ1x corresponding to the light emission amount at the time of main light emission obtained according to the formula will be explained.

(73) is a block to which data Δcs corresponding to the contrast between two parts is output, and an adder circuit (30
1), (302), (Qvfm2+△cs)+
(BY2 +Δcs) is calculated. Next, the subtraction circuit (
303), (304), Qvfm+ (Qvfmz+△cs)=α −...
・-= m(Bv2+△cs) −BVl−β
・・・・・・・・・c3]) is calculated, and the ROM(
305), (306) is the subtraction circuit (303),
The data α and β from (304) are log2(1-2-
''), converted into data corresponding to log2 (2β-1). (E) outputs data corresponding to the synchronized exposure time Tvs for flash photography, and the subtraction circuit (A) converts it into data corresponding to (Bv l
−Tv s ) is calculated. And the addition circuit (307
), (308) perform the calculation of Qvfmt+40g2 (1-2) (Bvt-Tvs)(-10g2(2β-1), respectively, and the subtraction circuit (309) calculates △fx-(Bvt-
T'vs) Dou"g2(2'-1)'l12yfm1-1
og2 (1-2) . . . 0 is calculated to calculate the apex value of the ratio between the preliminary light emission amount and the main light emission amount. This data is transferred to the D4 converter (31
0) is converted into an analog signal by the terminal (C2),
(j21) to the main light emitting section.

The reason why the apex value Δfx of the ratio between the preliminary light emission amount and the main light emission amount is calculated by Equation 64 will be explained. Transforming equation (1-2), 2 Q V f rn 1+△Ex-2Qvfm2+△
cs size △fx=2B■2+6cs-Tvs Bvt
−Tvs, , , , , , 032 From the equation (to), using the equation cn, o]), (Qvf
By eliminating m2+△cs) and (Bv2▗△cs),
2△fx, 2Qvfm+, (12-α)-2Bvt-
Tvs · (2β-1), and by taking 10g2 on both sides and rearranging, △fx shown in equation (to) is obtained.

During actual shooting, the main light emitting unit (FL2) is activated by the value 2Af x corresponding to △fx input via the terminal (j21).
The amount of light emitted from the preliminary light emitting section (FL+) is increased compared to the amount of light emitted from the preliminary light emitting section (FL+).

In the adder circuit (311), Qvfm+dou△fx =Qvf l-・-(7'-1)
The apex value Qv f 1 of the amount of light reflected from the subject due to the main light emission to the part where the light receiving element (PDl) receives light when the main light emission unit (FLI) emits light is calculated.
is calculated. Data Q from this adder circuit (311)
vf1 and data from the subtraction circuit (5) (Bvl -T
vs) is input to the subtraction circuit (312) and Qvfl
(Bvl T")-ΔL1-.-(8-1) is calculated, and the calculated data ΔL1 is converted by the ROM (313) into data corresponding to log2(2Δ"+1). - is a block in which data corresponding to the apex value Sv of film sensitivity of the film used is output, and data Sv from this block θ9), ROM
(313) data Iog2 (L1+1 to 2), and data from the subtraction circuit (BY] -TV S
) are respectively input to the adder circuit (314) and Avt-
(Bvt-Tvs)-1-1og2(2△L++1)
+Sv, , -1-w are calculated. This A■1 is
When the exposure time is TvS and the amount of light emitted from the main light emitting section (FL2) is increased by 2Af x than the amount of light emitted from the preliminary light emitting section (FLl), the area where the light receiving element (PI) +) receives light is properly exposed. This is the apex value of the aperture value.

The reason why the apex value Avl of the aperture value can be found using the formula will be explained. The conditions for proper exposure during flash photography are (2Qvf1+2Bvl-TvS), 2Sv 2Av1
．． 112.180. c! It is 4. Therefore, by eliminating Qv f 1 from equations (to) and (8-1), we get 2Bv1-1v8・(1+2△L1)・25v-2Av
I, and taking Iog2 on both sides, formula (b) is obtained.

(315) is a well-known display device, and a subtraction circuit (309) is a well-known display device.
) based on the data △fx from the main light emitting section (FI, +
), the aperture value is displayed based on the data Av1 from the adder circuit (314), and the synchronized exposure time is displayed based on the data Tvs from the block (7). (316) is a well-known aperture control device, and an addition circuit (
The aperture is controlled based on the data Av from 314). Further, (317) is a well-known shutter control device, which controls the exposure time based on data Tvs from the block screen.

(Margin below) αυ By the way, the explanation based on Figure 1 was only for the case where the amount of light emission Δfx necessary for the contrast to be Δcs can be derived unconditionally.However, in reality, There are various limitations such as the control range of the camera's aperture, the control range of the exposure time, the upper and lower limits of the amount of light emitted by the flash device, and the condition of the subject, so it may not be possible to obtain data on the amount of light that can be controlled. Therefore, when applying to an actual camera, it is necessary to take some countermeasures even when the controllable light emission amount data ΔEx cannot be determined.

The contents of calculations when such measures are taken will be explained below based on the block circuit diagram shown in FIG. In addition,
Figure 3 (one flow complete with Figures 3A, 3B, and 3C) is a flowchart of the calculation process in a specific countermeasure mode (corresponding to mode 1 described later), and it can be understood by referring to it. would be easy. In addition, in FIGS. 2 and 3, as an example, 27c521(ΔC
5=O), that is, when trying to control two different parts so that they receive the same amount of light, the following is an explanation of calculation (16).

The symbols used below will be explained. ΔfM corresponds to the maximum amount of light emission, and therefore, when 04ΔfX4ΔfM, the amount of light emission can be controlled. AVO is the open aperture value, AVM
is the minimum aperture value, so AvOl, ? Av4,
<AvM, aperture control is possible.

The subtraction circuit (321) has the following formula: Q vfm+-Q vfm2 = a
(30), and the subtraction circuit (322) calculates Bv2-Bvl-β cill. The discrimination circuit (323) sets the terminal (a□) to “High” when the output data α of the subtraction circuit (321) is α>0.
h″jkoL, a′=o Noah!: Kiha terminal (a2)
Set it to ``High''. On the other hand, the discrimination circuit (324)
When the output data β of the subtraction circuit (322) is β>O, the terminal (a3) is set to “High”, and when β-0, the terminal (a4) is set to “High”. Discrimination circuit (325)
, (326) are respectively Qvfm+.

It is determined whether the data of Qvfm2 is larger than the constant value data γ from the block (320), and Qvfm4
゜Q vfm2(r (When D, terminal (a5), (a6
) to “High”. This is Q v fm + ,
If Q v fm2 is less than a certain value γ, it is considered that the flash light does not contribute to exposure, and therefore the signal is used to ignore the amount of reflected light due to the flash light emission.

The subtraction circuits (327) and (328) are data Bvl,
Based on the data Tvs of the tuning limit exposure time from Bv2 and block (26), ite(B vl −Tvs ),
Calculate the data of (Bv2-Tvs). Discrimination circuits (330) and (331) each have data (Bvl
-Tvs), (Bv2-Tvs) block (
(BVI - Tvs ), respectively.
, (Bv2-Tvs) (When δ, terminal (a7)
.

Set (a8) to “High”. This is (Bvl −Tv
s).

If (Bv2-Tvs) is smaller than the constant value δ, it is considered that the amount of light due to constant light does not contribute to exposure, so the amount of light due to constant light (Bvl-Tvs), (Bv2-
This is a signal that ignores Tvs).

(332) is a decoder which sets only one terminal among the output terminals (b□) to (b, .) to "High" in response to the signals from the input terminals (a□) to (a8). Table 1 shows the relationship between the input and output of the decoder (332).

Table 1 In Table 1, “1” is a “High” signal, 0
” indicates a “Low” signal, and “da” indicates that it can be either “High” or II Low.

Next, the contents of the calculations in each case of condition mode 1 to positive shown in Table 1 will be explained with reference to FIG.

First, in the case of mode ■, terminals (λ, ) and (a3) are Hi.
gh" and the terminal (bl) becomes High".

In this case, Q vfml −Q vfm2 = a) QBV2
-Bvl-β〉0. Therefore, in the arithmetic circuit (333), Δfx-
(TSv2-fvs)+7-22 (1-2')-Q
vfm2-'y2 (2a1) (351 operations are performed.Value) The reason why Δfx is found by the formula is (1
-2) When Δcs=Q, 2 Q v f rn + 10Δf X 2 Q V
f m2 + Δfx = 2B v 2 - r v s -2
B v I - r v s (36). Therefore, using equations +30) and 131), Qvfml, B
When vl is deleted, 21 fx, 2Qvfm2, (2a-1)=2
B■2. (1+2-β), 2 Tvs, and by taking ~2 on both sides, the formula (to) is obtained. Operation (19) Δfx found by the arithmetic circuit (333) is sent to the discriminator circuit (334)
), it is determined whether OzΔfx,<21M.

When ozΔfx&ΔfM, the terminal (C2) becomes High'', which becomes a signal indicating that flash light emission can be controlled.

When Δfx (Q), the terminal (C3) becomes High'', which becomes a signal indicating that the light emission is too large even at the minimum light emission amount.

Δfx) 21M, the terminal (C0) becomes "High", indicating that the light emission amount is insufficient even at the maximum light emission amount.
When C, ) and (C3) are High'', it becomes a signal indicating that it is impossible to control the contrast ) 2 J c s to 1.

When the terminal (C3) is High, the arithmetic circuit (33
8), Avl = (Bvl-Tvs) +'y2(2ΔL1+1
)+SV...(To) (20) Calculate. Further, when the terminal (C2) is at °'H4gh'', the arithmetic circuit (338) performs the arithmetic operation based on Δfx calculated by the arithmetic circuit (333).

When the terminal (C□) is “High”, the arithmetic circuit (33
In 8), the following calculation is performed with Δfx=ΔfM.

The aperture value Avl calculated by this arithmetic circuit (338) is an aperture value at which the portion photometered by the light receiving element (PD□) is properly exposed. This calculated aperture value Avl is determined by the discrimination circuit (
339), it is determined whether AvO, Avl, or AVM. A%'O&Avl lAVM
In this case, the terminal (d2) becomes "High". At this time, if the terminal (C2) is also "High", the terminals (Av), (Tv), (
Δf), data Δfx from the arithmetic circuit (333)
, data A v l from the arithmetic circuit (338), and data Tv of the exposure time of the tuning limit from the block (a).
s is output. 2 Photographing is performed where J c s == t〇Terminal (C3) is “High” and terminal (d2) is “H”
i gh'', the selector (346) gives Δfx
=Q data and data A from the arithmetic circuit (338)
vl and data rvs from block (2) are output. In this case, in the arithmetic circuit (347), Δfx=Q
, Tvs.

Qvfm2. BV2, Svcy) Based on the data, ite Av2 = (Bv2-Tvs) + Ay2 (2
ΔL2+1)+SV...(9) (Δt2=Qvfm2-(Bv2-Tvs)) is calculated. This A v 2 is an aperture value at which the portion photometered by the light receiving element (PD2) is properly exposed. By the way, since exposure control is performed using Avl calculated by the arithmetic circuit (338), the two parts (the part where the light receiving element (PDl) measures light is the proper exposure) are Av2 - Avl = ΔC2
1elf). and,
-2.7 ΔC21 Otsu +2.3 is determined, and if this condition is not satisfied, the terminal (g2) is set to "High" and the warning device (
348) warns that the contrast between the two parts will be too high and the part measured by the photodetector (PD2) will exceed the latitude range of the color reversal film. In the case of a color reversal film, it is necessary to give such a warning because anything outside the range of -2.7 Ev and +2.3 Ev for the intermediate density portion will not be reproduced on the film.

Terminal (co) is “High” Te terminal (d2) is High
”, from the selector (346) Avl, Tv
Data of s and ΔfM are output and exposure control is performed based on this value, and A v 2 is calculated by the arithmetic circuit (347) in the same manner as described above, and -2, 7, <
If ΔC21&+2.3 is not reached, the warning device (34
8) gives a warning.

The terminal (C3) is High”, that is, the terminal (d
1) is “High”, that is, Avl) AVM
When the time comes, check if the steady light is too bright and you don't need a flash.
Alternatively, the distance to the subject is too short and the amount of light reflected by the flash light emission is too large. In this case, the logic circuit (
The output terminal (f2) of the terminal (f3) becomes High, the arithmetic circuit (345) operates, and the exposure calculation using only normal constant light is performed, Ava and Tva are calculated, and the output terminal (f3) of the terminal (f3) becomes High. becomes High”.This terminal ((2
6) The "High" signal from f3) is output to the terminal (go) via the selector (346) and sent to one input of the OR circuit (ORo).The other input of this OR circuit (ORo) is The signal from the main light emission start switch (S5) is input.Therefore, the terminal (g□) is “High”
, even if the switch (S5) is closed, the output of the OR circuit (ORo) remains “High” and the terminal (j
From □2), the main light emission is not performed even if the light emission start signal is applied.

In this case, the output Tva of the arithmetic circuit (345) is Tv
a (Tvs), the selector (346) may output the data of AVM, Tvs, Δfx=Q to emit the minimum amount of flash light.In this case, if the steady light is relatively dark and the subject is In such cases, there is an advantage of preventing camera shake even if the exposure is slightly overexposed.
Even when C) and (d□) become "High", (y) Ava and Tva are sent from the selector (346).

It is necessary to issue a warning based on the calculation result of the calculation circuit (347) based on Bv2.

(24) Terminal (C3) is “High” (Δfx(Q) and terminal (d
3) is High” (Av I (AvQ) (D
At this time, the arithmetic circuit (340) sets Avl=AvQ, Δfx=(Bvl−Tvs)+&y2(2Δd+,
)−Q v fm 1(39) Δd+ = (AvO−5v )−(Bvl −Tvs
) (Perform the calculation of 4Ql. (39)
The reason why Δfx is found by the formula is that the condition for proper exposure of the area measured by the photodetector (PD□) is 2Bv+-Tvs+2Qvfml+Δfx = 2AV
OSv (411), and by eliminating (AvO-5v) from equations (40) and (41), equation (to) is obtained.Δtx found by this arithmetic circuit (340) is determined by a discriminator circuit (341). It is determined whether 0<Δfx, <Δfy, and if 0<ΔExlΔfM, the terminal (e2) becomes “Hi”.
gh'', and from the selector (346), AvO, Δ
The fx and Tvs data are output, and the arithmetic circuit (347)
Then, when Av2 is calculated and a contrast warning is necessary, a warning is issued by the warning device (348).

When the terminals (C3) and (d3) are 'High', the arithmetic circuit (3
40) is performed when the aperture is calculated using Δfx = Q, and the subject is too dark, resulting in Avl (AvO), and Δfx is recalculated as Avl = AvQ. Δfx is ΔfX<0
(darkening the subject light), and the terminal (
C3) never becomes "High".

The terminal (el) is a )(i gh++ (ΔfX〉21
M), the terminal (d3) is “IIHigh” (Avl
(AvO) and Δfx is recalculated, so even if the flash light emitting device emits all the light, proper exposure will not be achieved. Therefore, in this case, the output (fl) of the logic circuit (343) is set to "High" and the arithmetic circuit (344)
) and operate Δ1+- Tvx==Bvl-(Qvfml+Δfl-412(2
1) (47J Δt I = (AvO−8v)−(Qvfml+Δ
fM) Perform the calculation of (43). The exposure time data Tvx is longer than the tuning limit data Tvx, thereby increasing the amount of contribution to the exposure by constant light to achieve proper exposure. (4
The reason why the exposure time that is the appropriate exposure can be obtained from the formula 2) is 2.
B v I Tv x+ 2 Q V frr+l+
Δf M == 2A V OS V L441 (
27) is the conditional expression for proper exposure, and (431 formula and (441
By eliminating the term (AVO-8v) from the equation, equation (42) is obtained. Then, from the selector (346), ΔfM
, AvO, and Tvx data are output. As with conventional cameras, if Tvx is longer than the camera shake limit exposure time, a camera shake warning will be issued, and if the exposure time is longer than the maximum controllable seconds, a warning will be issued and the exposure time will be It is desirable to do this at the maximum time limit. Also,
The arithmetic circuit (347) calculates Δfx, "fvx, Bv
2゜Qvfm2. Similarly, Av2 is calculated based on Sv and a warning is issued.

Discrimination circuit (334) (7) Terminal (C0) is high
”(Δfx>21M), the arithmetic circuit (338) calculates A v l as Δfx−ΔfM, and the discriminator circuit (338) calculates A v l.
39) terminal (d3) is “High” (Avl) AvO
), the terminal (f□) of the logic circuit (342)
becomes “I-1i gh”, and the arithmetic circuit (344)
Then, calculate Tvx using the formula 341, and perform the same operations as described above.

Terminal (cm) is “High”, terminal (dl)
When is 'High' (Av I ) AVM ),
An arithmetic circuit (340) calculates Δfx as Avl(28)=AvM, and a discriminator circuit (341) determines whether Δfx≦0. Terminal (
C2) becomes 81gh" (ΔfxhO), the selector (346) outputs Δfx, AVM, and Tvs calculated by the arithmetic circuit (340), and the arithmetic circuit (347) outputs the above-mentioned warning signal. Performs the calculation on the terminal (
C1) is α mountain ghII(Δfx)21M) and Δfx−Δ
Avl is calculated as fM and the terminal (d□) is High.
”(Avl)AVM), and Δ as AVI=AVM
Since fx has been recalculated, it will not become Δfx)21M, and the terminal (el) will not become "'High."

Also, when the terminal (C3) becomes "High" (Δfx(Q)), overexposure will occur even if the minimum aperture is set to AVM and the minimum light emission is performed.In this case, the logic circuit (343) The output (f□) becomes "High" and calculations for natural light photography are performed in the same way as described above.

Terminal (C2) is “High” (Q Δfx Δf
M), the terminal (d3) is “High” (Avl (A
vO), the arithmetic circuit (340) calculates ΔEx according to equation (39).

And the terminal (C2) is “High” (ΔExlΔfM
), the selector (346) returns AvO, Tvs
, ΔEx are output, and the arithmetic circuit (347) calculates AV2 for warning. Also, when Δfx) becomes 21M and the terminal (e□) becomes “'High”, the logic circuit (34
The output (fl) of 2) becomes "IIHigh", and the arithmetic circuit (344) calculates Tvx according to equation (42), and the selector (346) outputs AvQ, Tvx.
, 21M are output, and A v 2 is calculated. Note that Δfx(Q) and the terminal (C3) becomes "High"
“It will never become.

Terminal (C2) is “High” (0 Δfx & ΔfM)
Then, the terminal (dl) is “High” (Avl > AVM
), the arithmetic circuit (
In step 340), Δfx is calculated according to equation (39). Δ
When the terminal (C2) is High''' at fx\0, Δfx is output from the selector (346).

AvM and Tvs are output, and an arithmetic operation circuit (347) performs a contrast warning operation. Furthermore, when the terminal (C3) becomes "High" when Δfx(Q), the output (f2) of the logic circuit (343) becomes "High" and the calculation for natural light is performed. Arithmetic circuit (34
0) becomes Δfx)ΔfM, and the terminal (el) does not become "'High11°".

Figure 3 is a flowchart of the calculation contents in the case of mode ■ as described above, and as will be seen from this, when each calculated data exceeds the control range, other data is calculated using the data that exceeded the control range. Repair.

Next, the case of mode ■ will be explained. In this case, the terminal (a
) to (a8) are all “Low” and the terminal (b2)
becomes ``High''. In this case, Asahi Qvfml -Q
vfm2 = a (0BV2 - Bvl = β
<0. Therefore, in the arithmetic circuit (333), Δfx
-(Bv2-Tvs) +kg 2 (2-β-1
)-Qvfm2-4y2 (1-2a) (45
1 is performed to calculate ΔEx. This is (1-2)
In the case of 2 −1 in the formula, transforming this gives (2Bvl−
2Bv2), 2-Tvs=(2Qvfm2-2Qvfm
l)・2 J f x, and this formula and ((to), f
Using formula 311, Qvfml, BVI wo eraser, (61) 2Bv2-Tvs, (2-β-1)-2・(1-2
a) -2Qvfm2 Δfx, and by taking l0g2 on both sides and rearranging, Δfx shown in equation 49 is obtained.The following calculations are performed according to the flowchart of FIG. 3, as in the case of mode I.

In mode ■, terminals (a,), (a3),
(a6) becomes “High”. In this case Qvfm4- Qvfm2 = a) 0Bv2-
Qvf
The calculation is performed while ignoring m2. Therefore, equation (1-2) is 2 Q V fm++Δf x B v 2-r v
s −2B v I −r v s=2, and by eliminating BVI using equation (31), Δfx
-(Bv2-Tvs) -1-% 2 (1-2-
β)-Q v fm 1 (46) is obtained. This calculation of equation (46) is performed, and ΔE
x° is calculated. The following is the same as for mode ■ (
62) Calculations are performed according to the flowchart in Figure 3.

Note that the Z warning calculation performed by the calculation circuit (347) is a calculation using normal natural light, and AV2 is calculated.

In the case of mode (2), the terminal (a5) becomes "'High'" and the terminal (b4) becomes "High." in this case,
Qvfml −Qvfm2 = a (0BV2 −
Bvl −β〈O Qvfml(γ, and the amount of light reflected to the photometry section of the photodetector (pD,) due to flash light emission is considered not to contribute to exposure, so Qv
The calculation is performed while ignoring fml. So (1-2)
The formula is (2B v l 2 B v2 ), 2-I'
V S == 2 Q V fm2+Δfx,
When Bvl is eliminated using equation (31), Δfx−(BV
2-Tvs )-1-%2 (2-β-1) -Qv
fans (471 is obtained. Arithmetic circuit (333)
calculates Δ1x by performing the calculation of formula 471.

In this case, Qvfml is ignored, so the arithmetic circuit (34
5) calculates Bl+5V--rVs=AVl. If AvOI Avl is 1kvy and Q, <Δfx, <41M, selector (346
) outputs Avl, Δfx, and Tvs. Also A
If v Q , <Av l & AvM and O> ΔEx, the selector (346) outputs Avl, Δfx=Q, “rvs
is output, and the arithmetic circuit (347) calculates Tvs, Δfx=Q
, Qvfm2, Bv2 (7) Calculate Av2 based on the data, then Av2-AVI-Δc 21 (3
81 is calculated, and if it is not -2,7,<ΔC2+O+2.3, the terminal (g2) is set to "High" and the warning device (3
48), a warning is issued that the contrast between the two photometric sections is too high. Also, if AVOI Avl l AVM is ΔEx)ΔfM, the selector (346) will output Av
l, ΔfM.

Tvs is output, and a calculation circuit (347) performs a warning calculation.

Avl (If AvO, the exposure time is T v s, which will result in underexposure. In this case, Av I = Av O
Then, calculate B v I + S v - AvQ = Tvx, and when 0 ∆fxf∆fM, AvO.

Tvx, Δfx, when O>Δfx, AvO, Tvx
.

When Δfx=Q, Δfx)ΔfM, then AvQ, T
vx.

ΔfM is output from each selector (346), and a calculation circuit (347) performs a warning calculation.

If AVI>AVM, the exposure time will be overexposure at T v s. Therefore, in this case, the calculation BvI-1-Sv-AVM:=Tvx is performed. In this case, since Tvx ) Tvs cannot be used, flash photography cannot be performed, so the terminal (f3) is set to "H".
Then, from the selector select A%IM,
Tvx data is output and the terminal (gl) is “High”.
h', the output (j02) of the OR circuit (OR6) remains "High" and no flash light is emitted.

In addition, in the arithmetic circuit (347), Bv2 +Sv -Tvx == Av2Av2- A
vu-ΔC21 is calculated, and if it is not -2,7zΔC2+&+2.3, the terminal (g2) is set to "High" and the warning device (3
48) to give a contrast warning.

In mode ■, terminals (a□), (a3),
(, a7) becomes “High”, and at this time, Qvfml −Qvfm2= a ) 0Bv2 −B
vl = β〉0 BvI-Tvs (δ. Therefore, it is considered that the amount of light Bvl-Tvs due to the steady light incident on the photometry section of the photodetector (PDl) does not contribute to exposure, so (Bvl - Tvs ) The term is ignored. Therefore, equation (1-2) becomes (2Qvfrn+
−2Qvfrn2 ), 2Δf x = 2B v
2-Tv s, and by eliminating and rearranging Qvfml according to the formula (to), Δfx = (Bv2-Tvs)-Qvfm2-A+22
(2”-1) (48).Arithmetic circuit (333)
(481 formula is performed, and the following calculations are performed in accordance with the flowchart of FIG. 3 as in the case of mode I.

In the case of mode ■, the terminal (a8) becomes "High" and Qv
fml −Qvfm2= a (OBV2−Xen1=β〈
0 Bv2-Tvs (δ).Therefore, the photometry of the photodetector (PD2) (light amount Bv2-Tvs due to steady light incident on the father part is considered not to contribute to exposure, so ignore (Bvs-Tvs)) Therefore, equation (1-2) is 2Bvl
−Tvs=(2Qvfm2−2Qvfml), 2Δfx
Then, if we eliminate and rearrange Qvfml using the formula (to), we get Δfx = (BvI-Tvs)-Qvfm2-1ag2
(1-2a) 19), and the arithmetic circuit (333) performs the calculation of equation (49) to calculate Δfx. The following calculations are the same as in mode ■.

In the case of mode ■, terminals (a□), (a3), (a6),
(a7) becomes "High". Therefore, Qvf
ml −Qvfm2 = a) QBv2 − B
vl −β〉O Qvfm2 (γ Bvl −Tvs (δ), and Qvfm2, (B v t −Tv
The term s ) is ignored in the calculation. In this case (1-2
) formula is 2 Q V frn ++Δfx=2Bv2-T
vs (36) Δfx=(BV2-Tvs)-Qvfml
The calculation (50) is performed by the calculation circuit (333), and the following calculation contents are the same as in the case of mode I.

In mode ■, terminals (a5) and (a8) are High.
” and Qvfml −Qvfm2 = a (0Bv2 −
Bvl −βkuO Qvfm hot γ BV2−Tvs (δ becomes. Therefore, Qvfml and (Bv2−Tvs
) terms are ignored in the calculation. Then, (1-2) formula %
The computation of the formula % (511) is performed in the arithmetic circuit (333), and the following computations are similar to those in mode (2).

In mode ■, terminals (a2) and (a4) are “High”.
”, and Qvfml = Qvfm2 Bvl = BV2. In this case, ΔEx takes any value from O to Δfy and becomes 2Qvfm1 + ΔfX + 2BVl −Tvs = 2Qvf
m2+Δfx+2Bv2-Tvs, and the two parts are necessarily controlled to have the same brightness. In this case, the terminal (b9) of the decoder (332) is “High”.
h” and the calculation described below is performed.The calculation circuit (338) calculates ΔEx−ΔEc(Δfc=ΔfM/2)
and Qvfml, Bvl, Tvs, Sv
Based on Av+=(Bvl-Tvs)+10g2(2ΔLl+1
)+SV (341Δt+-4Qvfm+10Δfc)
-(Bvtodvs) is calculated. That is, the aperture value Avl that provides appropriate exposure when the amount of light emitted by the flashlight emitting device is set between the minimum light emission and the full light emission is calculated. Then, in the discrimination circuit (339), Avo,<Avl fAv
M (D) It is determined whether the condition is satisfied, and when the condition is satisfied and the terminal (d2) is 'High', the selector (346) outputs the data of Δfc, Avl, and Tvs.

When Avl<AVO, the terminal (d3) becomes “High”
” At this time, the amount of light emitted is insufficient and the exposure is insufficient, so A.
As vl =-AvQ, the arithmetic circuit (340) calculates Δfx = (Bl-rvs)+'F2(2Δd+).

-Q v fm I (39) Δdl=(Av(+-5v)-(Bvl-Tvs)
+40) to calculate ΔEx. Then, the discrimination circuit (341) discriminates whether ΔExlΔfM or not, and if Δfx<ΔfM, the terminal (e
2) becomes "High" and the selector (346) outputs AvO.

Data of ΔEx and Tvs are output. Δfx) Δfy
Therefore, when the terminal (el) is "'High'", even the maximum amount of light emission will be insufficient. Therefore, the logic circuit (
342) output terminal (fl) becomes “High”,
In the arithmetic circuit (344), Avl=AvO, Δfx−Δf
M Toshite Qvfml, Bvl, Sv (y)
Based on data Tvx=Bv+-(Qvfml+Δf
u ) −4y2 (2Δ”−1) +42)ΔL l
= (AvO-8v)-(Qvfml+ΔfM
) (43) is performed to calculate Tvx, and the selector (346) outputs Avo, ΔfM, Tvx.
Output the data. (69) Oh, Δfx calculated by the arithmetic circuit (340) is a recalculated value because the amount of light emission or Δfc is insufficient, so it is ΔE.
x (never becomes Q.

Avl calculated by the arithmetic circuit (338) is Avl) A
When it becomes VM, the amount of light emitted is too large at Δfc, and the terminal (d□) of the discrimination circuit (339) becomes High.
”, and the arithmetic circuit (340) calculates A v l2 AV
Δdl−Δfx=(Bvl−Tvs)+%2(21)−Qvfm as M
l (391 Δdl=(AVM-5V)-(Bvl-Tvs)) to recalculate ΔEx. Then, ΔEx≦0
If so, the terminal (e2) of the discrimination circuit (341) is "
AVM from the selector (346),
Data of Δfx and Tvs are output. Also Δfx
(If the terminal (e3) is "High" in Q, the output terminal (f2) of the logic circuit (343) becomes "High", normal natural light photography calculations are performed, and Ava.
The Tva data is calculated, and the terminal (f3) is set to “H”.
This causes the selector (346) (
40) The data of Ava and Tva are inputted to the terminal (gl
) becomes "High'", the flashlight emitting device remains non-emitting and photography is performed. Further, in this case, since the amount of light emission is too large at ΔfC, Δfx is recalculated, so ΔEx)ΔfM will not be achieved.

In the case of Mo1'X, XI, X[l, XI (7), respectively. Therefore, as seen from equation (1-2), 2 B v IT v S +2 Q V tri +
+Δfx=2Bv2−Tvs+2Qvfm2+Δfx In the case of mode X−■, ΔEx that satisfies the above equation cannot be calculated. Therefore, in these cases, the terminal (blo) of the decoder (332) becomes ``High'', and the mode
Perform the same calculation as in the case of mode □ to calculate Avl or Δfx or Tvx or Ava, Tva, which will give the proper exposure for the part photometered by the photodetector (PD□), in the same way as in the case of mode ■, and also apply this data to to control exposure. In this case, it is necessary to calculate Av2 in the arithmetic circuit (347) based on the data from the selector (346) and issue a contrast warning.

In the circuit of Figure 2, 2Bv1-TvS+2Qvfml+Δfx-2BV2-
rVs +2Qvfm2+Jfx Calculate Δfx that satisfies (1-2), and when Δfx (Q or Δfx)ΔfM, it is judged that it is impossible to control the contrast to 2Δcs-1 (Δcs20), and Δfx = Q or ΔEx
-Δ1M, Bvl, Qvfml, Tvs
, Sv, the photometry section of the photodetector (PD, ) calculates the aperture value Avl for achieving proper exposure. However, the contents of the calculation can also be modified as described below. Δfx (Q or Δfx) When ΔEy, Δfx
=Q or Δfx-ΔfM, 2Bv+ -Tvx +2QvfrrB = 2Bv2
-Tvx+2Qvfm22Bv1-TvX+2Qvfm
1+ΔfM=2Bv2−Tvx+2Qvfm2+ΔfM
If TvX is within the range that allows flash photography, the exposure time is controlled based on the calculated Tvx, and if Tvx is outside the range, the limit value is set to Tvx and Avl may be calculated. In this way, the contrast will be 27cs-1 (ΔC5
=O) has the advantage of widening the controllable range. In addition, T
The 8 operations to find vx are: Qvf+n+ -Qvfm2 =
a (0(30)BV2- Bvl = β< O(
3] + Δfx d ΔfM As an example, Qvf
Delete and organize ml and Bvl, and get Tvx = B
v2-IJIv2 (2-β-1) -Qv fm2
'y2(1-2a)-ΔLM(521), and Tvx can be calculated by performing the calculation of this formula (521).In addition, as described in the explanation using FIG. 2, α
, the calculation formula for calculating rvx depending on the conditions of β is different (46
) It's coming. This is shown in a block diagram in FIG. 4, in which the output Δfx of the arithmetic circuit (333) is determined, and Δf
x) Δfv and the terminal (C1) is “High”, or Δfx (Q and the terminal (C3) is “’High”
When this happens, the arithmetic circuit (351) outputs the data of Δ1x=0 or Δfx−ΔfM, Bvl, Qvfml
, Based on the data of Bv2゜Qvfm2, the terminal (
Calculations are performed in the same manner as described above depending on the states of bl) to (b8). Then, this calculated Tvx data is sent to the arithmetic circuits (338), (340) and the data selector (
346).

In addition, according to the above embodiment, each block in the block diagram is shown as a circuit device having an independent function. However, those skilled in the art will find it relatively easy from this example to replace these organically coupled circuit devices with a microprocessor or microcomputer. That is, a predetermined program for executing a series of processes in the above embodiment is stored in the microcomputer's built-in storage means or external storage means (44).
) The arithmetic means, control means for arithmetic operations, input/output means, etc. are organically integrated with the program, and predetermined control is achieved by operating them.

Further, in this embodiment, two cases of light-receiving elements are shown and explained. However, in other embodiments, one of these two methods may perform average photometry for the entire screen, and the other may perform partial photometry at the center.

In yet another aspect, five light receiving elements may be provided, one in the center and the other four in the four corners of the photographic screen, so that the two parts can be manually selected. Alternatively, it is also possible to automatically select a portion where the absolute value of the difference between the central portion and the other four portions is the largest in the measured value when the auxiliary light is emitted, and the central portion. Furthermore, in this embodiment, two portions may be provided in which the absolute value of the difference between the five measured values is maximum.

Effects As detailed above, the photometry device according to the present invention can quantitatively derive the value of the factor that controls the contrast between each part of the shooting screen using the auxiliary light source, so it can quantitatively determine the contrast, which was previously impossible. This enables controlled shooting.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of an embodiment that can accommodate various conditions,
FIG. 3 is a flowchart. FIG. 4 is a block diagram of main parts as a modification of FIG. 2. PDPD, , Light receiving element, FL Auxiliary light source, Dl. I + 2 D2. OAl, 0A21AS1. AS21B'r11.
BT121B T 2 t・B ”[” 22・Dll
・012・D21・D22・C11・C,, AS3. A
S4...Functional devices constituting the photometric circuit, 7 to 22
, 26, 27, 73, 49, 301 to 314... Functional devices forming the processing circuit. Patent applicant Minolta Camera Co., Ltd. Agent
Person Patent attorney Tamotsu Maede and 2 others (47) 148- to Figure 4 340, 346

Claims (1)

[Scope of Claims] (1) At least two light-receiving elements for photometering multiple parts of a photographic screen, an auxiliary light source, and a first type corresponding to the amount of light received by each of the light-receiving elements when the auxiliary light source emits light. a photometric circuit that outputs a second type of signal corresponding to the amount of light received by each of the light receiving elements when the auxiliary light source is not emitting light; Based on the type of signal, during actual shooting, the light amount ratio that contributes to exposure to the photoreceptor portion corresponding to at least two portions of the plurality of portions of the photographing screen is set to a predetermined value. A photometry device for photographing using auxiliary light, comprising a processing circuit that derives a value of a first factor to be controlled. (2) A second factor output device that outputs a value of a second factor that controls the light amount ratio, and the processing circuit also uses the value of the second factor to determine the value of the first factor. A photometry device for photographing using an auxiliary light according to claim (1). (3) A light intensity ratio signal output device that outputs a signal corresponding to the light intensity ratio of the predetermined value is provided, and the processing circuit also uses the signal from the light intensity ratio signal output device to determine the value of the first factor. A photometry device for photographing using an auxiliary light according to claim (1) or (2), which is configured to derive the following. (4) The value of the first factor is the ratio of the amount of light emitted from the auxiliary light source during measurement to the amount of light emitted from the auxiliary light source determined in advance during photography. 3) A photometry device for photographing using the auxiliary light according to any of the items above. (5) Photometry for photography using an auxiliary light according to any one of claims (2) to (4), wherein the value of the second factor is an exposure time during photography. Device. (6) The processing circuit determines, based on the first type of signal and the second type of signal, that photography with a light amount ratio of the predetermined value is impossible during actual photography. A photometric device for photographing using an auxiliary light according to claim (1), further comprising a discriminating circuit that can perform the following. (7) The processing circuit determines, based on the first type of signal and the second type of signal, that photography with a light amount ratio of the predetermined value is impossible during actual photography. Claim (2) EM also includes a discriminating circuit that can
(8) A photometering device for photographing using an auxiliary light according to any one of paragraphs (5) to 5), further comprising a device for outputting a film sensitivity signal, and the discrimination circuit detects the amount of light at the predetermined value. When determining that it is impossible to take a picture with a high ratio, the processing circuit processes first and second types of signals corresponding to one of the plurality of parts of the picture plane, the film sensitivity signal and the film sensitivity signal. Claim (7) further comprising a circuit for calculating an aperture value so that one of the plurality of portions is properly exposed based on the value of the second factor.
) A photometering device for photographing using the auxiliary light described in item 2. (9) The processing circuit is a circuit connected so that the predetermined value of the first factor can be used in calculating the aperture value. Photometering device used for photography.