JPH03287241A - Ttl automatic dimming camera - Google Patents

Abstract

PURPOSE:To carry out the flash photographing of a main object with a proper exposure by determining a dimming level from a photometric signal obtained when preliminary flashing is carried out. CONSTITUTION:This camera is provided with a flashing means 101 capable of regular and preliminary flashings, a photometric means 102 dividing a field into plural regions, carrying out the photometry of each reflected light from plural regions by the preliminary and regular flashings of the flashing means 101, and outputting each photometric signal, a level determining means 103, a level correcting means 104, and a dimming means 105. The deciding means 103 determines the dimming level based on each photometric signal when the preliminary flashing is carried out. When the determined dimming level is out of a prescribed range set in advance, the level correcting means 104 corrects dimming so as to be set within the prescribed range. Further, the dimming means 105 stops the regular flashing when a prescribed dimming evaluation value accumulated and calculated based on each photometric signal reaches the determined or corrected level, in the regular flashing. Thus, the main object is always photographed with the proper exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a TTL automatic light control camera that divides a field into a plurality of photometric areas and performs light adjustment based on photometric signals from each area.

B. Prior Art For example, Japanese Patent Application Laid-Open No. 15626/1983 discloses the following automatic light control camera. This camera performs a preliminary flash prior to the main flash during flash photography, divides the light reflected from the subject into light meters, determines the position of the main subject from the metering signal for each area, and uses the determination results to determine the position of the main subject in each area. The amount of weighting is determined for the main light emission, and the main light emission is stopped when the total value of the output of each area weighted during the main light emission reaches a predetermined dimming level.

Problems to be solved by the C0 invention However, with such conventional automatic light control cameras,
Since the light control level for determining whether to stop the main light emission is set to a constant value, there is a risk that the main subject will be overexposed or underexposed.

A technical problem of the present invention is to always ensure that the main subject is properly exposed.

To explain with reference to FIG. 1, which is a diagram corresponding to the claims, the TTL automatic light adjustment camera according to the invention of claim 1 includes a main flash that emits light to take a flash photograph of a subject, and The flash unit 101 is capable of preflashing before the main flash, and the field is divided into a plurality of areas, and each reflected light from the plurality of areas due to the preliminary flash and main flash of the flash unit 101 is photometered. a photometric means 102 that outputs each photometric signal at the time of preflash; a level determining section 103 that determines a dimming level based on each photometric signal at the time of preliminary flash; In some cases, the level correction means 104 corrects the level to be within a predetermined range, and the predetermined dimming evaluation value, which is cumulatively calculated based on each photometric signal during the main flash, is adjusted so that it falls within a predetermined range. The light control device 105 is provided with a dimming means 105 that stops the main light emission when the light emission level reaches the level, thereby achieving the above technical problem.

Similarly, to explain with reference to FIG. 1, the TTL automatic light adjustment camera according to the invention of claim 2 includes a flash unit 101 that emits light to take a flash photograph of the field, and a flash unit 101 that divides the field into a plurality of areas. Then, a photometry means 102 that measures each reflected light from the plurality of areas due to the light emission of the flashing means 10-1 and outputs each photometry signal, and a light control level is determined based on each photometry signal at the initial stage of light emission. a level determining means 103 for determining the level, and a level correcting means 104 for correcting the determined dimming level so that it falls within the predetermined range when it is outside a predetermined range; and after the initial stage of light emission, A dimming means 10 that stops emitting light when a predetermined dimming evaluation value cumulatively calculated based on each photometric signal reaches the determined or corrected dimming level.
5.

80 Effect (1) The invention level determining means 103 of claim 1 determines the dimming level based on each photometric signal at the time of preliminary light emission, and the level correcting means 104:
If the determined dimming level is outside the predetermined range, it is corrected so that it falls within the predetermined range. During the main light emission, the light control means 105 stops the main light emission when a predetermined light control evaluation value cumulatively calculated based on each photometric signal reaches the above determined or corrected 4-light level.

(2) The invention level determining means 103 of claim 2 determines the dimming level based on each photometric signal at the initial stage of light emission, and the level correcting means 104 adjusts the determined dimming level to a predetermined level set in advance. If it is outside the range, it is corrected so that it falls within the predetermined range. After the initial stage of light emission, the light control means 105 stops light emission when a predetermined light control evaluation value cumulatively calculated based on each photometric signal reaches the determined or corrected light control level.

F. Example An embodiment of the present invention will be described with reference to FIGS. 2 to 12.

FIG. 2 is a diagram showing the configuration of a TTL automatic light adjustment camera.

The light flux (stationary light) that has passed through the photographic lens 2 is reflected by the mirror 3 in the mirror-down state shown by the broken line, and is reflected by the screen 4.
．． A portion of the light passes through the pentaprism 5 and is guided to the eyepiece lens 6, and the other portion passes through the condenser lens 7 and is guided to the exposure calculation photometric element 8. Further, when the release button 32 shown in FIG. The thus-obtained subject light is guided to the film FI, and the film FI is exposed.

In addition, during flash photography, the electronic flash device 11 emits main light directly to the shutter 10 to illuminate the subject, and the reflected light from the subject reaches the film surface via the photographic lens 2, and the light flux reflected on this film surface is The light is received by the light receiving element 13 for dimming via the condensing lens array 12 . Furthermore, the camera of this embodiment is capable of preflashing to check the reflectance distribution of the subject before the main light emission, and the reflected light from the subject due to this preflash is emitted before the shutter 10 is opened. The light is then reflected by the curtain surface and received by the light receiving element 13.

As shown in FIG. 3, the light-receiving element 13 includes a divided light-receiving element 13a corresponding to a circular photometry area in the center of the field, and a photometry area in the shape of an arc cut out of a rectangle at the periphery of the field. Corresponding divided light receiving elements 13b to 13e are arranged on the same plane. That is, in this embodiment, the field of view is divided into five photometry areas and divided photometry is performed. Further, the condensing lens array 12 is arranged on the left, middle,
Three lens parts 12a to 1 corresponding to the three blocks on the right
2c.

FIG. 4 shows the exposure area 20 on the film surface, the light receiving element 13,
3 is a diagram showing the optical positional relationship of the condenser lens array 12. FIG. The exposure area 20 of one frame on the film surface is divided into a circular part 20a at the center and four parts 20b to 20 around the periphery, similar to the field of view.
When divided into five regions e, the light receiving element 13 shown in FIG.
The left, middle, and right three blocks a to 13e are the left half, center, and middle blocks of the film exposure area 20 via the three lens portions 12a to 12c of the condenser lens array 12, respectively, as shown by broken lines. It is facing the right half. Furthermore, the five divided light receiving elements 13a to 13e of the light receiving element 13 are
Since the shape of each area is made to match the film exposure area 20, the brightness of each of the five areas 20a to 20e is measured separately.

FIG. 5 shows a block diagram of the control system, and the CPU 31, which controls the entire sequence of the camera, has a release button 32. The shutter 10 is connected, as well as the aperture 9 in the photographic lens 2 and the lens information output circuit 33.

Furthermore, the CPU 31 includes a photometry circuit 34 that performs a photometry operation based on the output from the exposure control photometry element 8, and a light control circuit 34 that performs a photometry operation based on the output from the light receiving element 13, that is, the divided light receiving elements 13a to 13e. Circuit 40 and I that reads the ISO sensitivity of the loaded film FI from the DX code
The SO sensitivity detection circuit 35 and the light emission control circuit 36 of the electronic flash device 11 are connected.

Here, similarly to the light receiving element 13, the exposure control photometric element 8 is divided into five divided photometric elements 8 corresponding to each photometric area of the subject.
It consists of a to 8e. The lens information output circuit 33 includes a lens ROM that stores lens-specific information (open aperture value, exit pupil distance, etc.), and a lens encoder that detects the photographing distance from the focusing position of the photographic lens 2.

FIG. 6 shows details of the dimming circuit 40, which includes amplifiers 41a to 41e that amplify the outputs of the divided light receiving elements 13a to 13e, and amplifiers 41a to 41e that amplify the outputs of the divided light receiving elements 13a to 13e, and It has gain setters 42a to 42e that respectively set amplification factors of 41e to 41e, and each of the gain setters 42a to 42e includes a D/A converter that converts a digital signal from the CPU 31 into an analog signal.

In addition, in response to a command from the CPU 31, there are integrating circuits 43a to 43e that integrate the outputs of the amplifiers 41a to 41e during the preliminary light emission over time, and each amplifier 41 during the main light emission.
An addition circuit 44 that adds the outputs of a to 41e, and a CPU 3
An integrating circuit 45 integrates the addition result of the adding circuit 44 over time in response to a command from the CPTJ 31, and converts the dimming level as an analog signal (described in detail later) calculated and output by the CPTJ 31 into a digital signal. A conversion circuit 46 that performs
A comparator 47 is provided which compares the converted dimming level with the output of the integrating circuit 45 and outputs a light emission stop signal when the output of the integrating circuit 45 reaches the dimming level.

Next, the CPU is
The control procedure for the flash photography operation using 31 will be explained.

FIG. 7 is the main flowchart, in which step S1
When the release button 32 (FIG. 5) is pressed halfway and then fully pressed in , the processing from step 82 onwards is started. First, in step S2, the ISO sensitivity detection circuit 35 detects the Is○sensitivity S of the loaded film.
v is read, and then, in steps 83 to S5, the maximum aperture value F0. The exit pupil distance P0 and the photographing distance X are respectively read and the process proceeds to step S6. The photographing distance X is a value obtained by detecting the position of the lens driven by a half-press operation of the release button 32 using an encoder.

In step S6, photometry using steady light is performed. That is, the outputs of the above-mentioned 5-divided photometric elements 88 to 8e (FIG. 5) are input into the photometric circuit 34, and the photometric circuit 34 logarithmically compresses the luminance values EVn (n=1 to 5) corresponding to each photometric area.
Load. Here, in this embodiment, the value of n from 1 to 5 means the five photometric elements 88 to 8e or the divided light receiving element 13a.
-13e, respectively. Next, in step S7, each read luminance value EVn and IS
The constant light exposure BV is calculated from the O sensitivity Sv.

This calculation method is used, for example, in Japanese Patent Application Laid-Open No. 1285/1999 by the present applicant.
A method such as that disclosed in Japanese Patent No. 925 is used.

Thereafter, the process proceeds to step S8, where the calculated constant light exposure B
The shutter speed TV and aperture value AV are determined from V, and in step S9 the mirror 3 is raised from the state shown by the broken line in FIG. 2 to the state shown by the solid line. Next, in step S10, the aperture 9 is stopped down to the aperture value determined in step s8, and in step Sll, a light emission signal is output to the light emission control circuit 36, and the electronic flash device 11 is pre-flashed with a predetermined small amount of guide number NO. let

This pre-emission light flux is reflected by the subject and sent to the photographing lens 2.
is transmitted and formed as a primary image on the curtain surface of the shutter 10. This primary image is divided into five parts, each of which is sent to the five divided light receiving elements 13 via the condensing lens array 12 shown in FIG.
The light is received by a-13e, respectively. Each divided light receiving element 13
A to 13e sequentially input signals corresponding to respective amounts of received light to amplifiers 41a to 41e of the dimming circuit 40 (FIG. 6).

The amplifiers 41a to 41e amplify the input signals by the amplification factors set by the gain setters 42a to 42e (all amplification factors are 1 during this preliminary light emission), and manually input the signals to the integrating circuits 43a to 43e. do. The CPU 31 performs step S1
In step 2, an operating signal is output to the integrating circuits 438 to 43e, and in response to the operating signal, the integrating circuits 43a to 43e integrate the amplified signals with respect to time and input the integrated signals to the CPU 31. This input signal is hereinafter referred to as divided photometry signal BP.
Called n (n=1 to 5).

12- After that, steps 813 to S are executed in the CPU 31.
Each process of 17 is performed in order, and the details of these processes are shown in the flowcharts of FIGS. 8 to 12.

FIG. 8 shows details of the lens correction and element area correction processing (step 513 in FIG. 7) for the divided photometric signal BPn, and first, in step 5131, n=0. Next, in step 5132, n is incremented by l, and in step 5133, a lens correction coefficient L (n) is calculated based on the following equation.

L (1) = 1 L (2) = 1-(1,2xlO-3) ・POL
(3)=1−(1,2X10−3)・p.

L (4)=1+ (1,7X10-”) ・POt
, (5)=1+ (1,7xlO-3) ・p.

Here, PO indicates the exit pupil distance of the photographing lens 2. Next, in step 5134, the element area correction coefficient S (n) stored in the memory in advance, that is, S (1)=1. S
(2)=0.8. S(3)=O.

B, S (4)=j, 3. S(5)=1.3 is read, and in step 5135, the divided photometric signal BPn is corrected based on BPn4-BPn-L(n)/S(n). These processes are performed until it is determined that n=5 in step 8136, and thereby correction based on the lens and element areas is performed on all the divided photometric signals BPn of the five photometric areas.

That is, the exit pupil distance po of the photographic lens 2 and the light receiving element 1
The light receiving conditions of the above-mentioned light receiving elements 13a to 13e differ depending on the area and position of 3a to L3e. Therefore, in the process shown in FIG. 8, the above correction process is performed in order to evaluate the photometric signals of all the light receiving elements under the same conditions.

Next, the CPU 31 selects Hi in step 514 (FIG. 7).
Lo cut processing (effective photometry area determination processing) is performed. In FIG. 9 showing the details, first step 51401,
51402, set M=O, n=0, then step 51
403 to S1410, the above five divided photometry signals BPn
The following processing is performed on (the value corrected in step S13) in order.

That is, in step 51404, the divided photometric signal BPn
Determine whether or not satisfies. Here, GNO is a guide number at the time of preliminary flashing, AV is the aperture value (apex value) calculated in step S8, X is the photographing distance, and K1 is a constant. If step 81.404 is affirmed, the process proceeds to step 81405, where the divided photometric signal BPn is set to zero; then, in step 5L406, this photometric signal BP
The weighting of n is performed by setting the quantity Dn to zero and proceeding to step 81411.

Here, the processing in steps 51404 to 51406 will be described in detail.

For example, if there is an object with high reflectance such as a mirror or a gold folding screen in the subject, or if there is an object in front of the main subject, the divided photometry signal BPn of that area will be
is extremely large, and if you perform a light adjustment operation taking this photometric signal into consideration, there is a possibility that the main subject will be underexposed. Therefore, in the processing of steps 51404 to S14.06 described above, if the photometric signal for such a high reflectance subject is larger than the exclusion value, it is determined that the amount of light is excessive, and the photometric signal BPn is set to zero, and the photometric signal BPn is set to 1. For weighting, the quantity D n is also set to zero. Since this reference value is based on the aperture value AV and the photographing distance X at the time of preliminary light emission, it has the following effects.

In other words, even if the guide number for preliminary flash is constant, the value of the photometric signal will vary depending on the aperture value AV and shooting distance value. For this reason, if the reference value for determining whether the amount of light is excessive is a constant value, there is a risk that a subject that should be excluded may not be excluded if the shooting distance is far and narrowed down, and conversely, the shooting distance When the aperture is close to wide open, there is a risk that photometric signals that should not be excluded may be excluded.

Therefore, in this embodiment, the reference value is determined by the above-mentioned formula, and according to this, the closer the shooting distance or the more open the aperture value is, the higher the reference value becomes, so the above-mentioned inconvenience is completely resolved. be done.

On the other hand, if step 81404 is negative, the process proceeds to step 81407, and it is determined whether the photometric signal BPn is smaller than the reference value 2 or not. If step 51407 is affirmed, the process proceeds to step 51405, and if negative, the process proceeds to step 81408. Contrary to the above, for example, if there is a large space behind the main subject and the amount of reflected light is small and the photometry signal BPn is too low, this process is performed to prevent the main subject from being overexposed.
This is a process to exclude n. In this case, since the photometric signal BPn is originally small, there is no need to change the reference value according to the aperture value AV or the photographing distance n, and a constant may be used.

Above step 5140.4. The photometric signal BPn that was not excluded in any of S14.07 is
14. Leave the value as is at 08, then step 51
In step 409, the amount of weighting corresponding to the photometric signal BPn is set to one. In step 51410, variable M is incremented by 1. Here, among the five photometric areas in the object field, the area where the photometric signal BPn is not excluded corresponds to the effective photometric area. Further, the variable M represents the photometric signal BPn that is not excluded, that is, the number of effective photometric areas.

When the process shown in FIG. 9 is completed, step 515 (step 7
The process proceeds to Fig. 3), and the process of determining the reflectance distribution Rn of each photometric area of the object scene is performed.

In FIG. 10 showing details of step S15, first, in steps 8151 and 8152, Q=O, n=O, and then in steps 8153 to 5155, each photometric signal B
Find the total sum Q of Pn (Q=Q+BPn). Here, since the above-mentioned photometric signals for excessive and insufficient light quantity are set to zero in the process of step S14, substantially only the photometric signals of the effective photometric area are added. Then step 5156
In steps 5157-8159, the reflectance distribution Rn of each photometric signal BPn is determined based on Rn = B P n /Q, where the total reflectance of the photometric signal BPn is l. At this time, the reflectance distribution of the photometric signals excluded in step 814 naturally becomes zero.

Thereafter, the process proceeds to step 816 (FIG. 7), a dimming level calculation process. Here, the light control level indicates the level of the photometry signal at which the main light emission of the electronic flash device 11 should be stopped during flash photography.

To explain step 816 in detail with reference to FIG. 11, first, in step 81601, the dimming level LV is set to zero,
Next, in step 81602, n=0 and step 81
Proceed to 603. In steps 51603 to 51606,
A process is performed to determine the dimming level LV according to the number M of effective photometry areas and each reflectance distribution.

That is, in step 81604, it is determined whether the reflectance distribution Rn of each photometric signal is equal to or greater than 17M (this corresponds to the average value of the reflectance distribution Rn in the effective photometric class 9- area), and if it is affirmative, That is, if the reflectance distribution Rn of the photometric area is equal to or greater than the average value, the process advances to step 51605 and the dimming level LV is incremented by 0°02. Further, if step 81604 is negative, that is, if the reflectance distribution Rn of the photometric area is less than the average value, step 8
Proceed to 1606 and set the dimming level to ro, 02XRn/MA
Step forward by X(R)J (where MAX (R) is the maximum value of R1-R5).

The above processing is for the case where the dimming level LV becomes 0.02x5=0°1 when all five reflectance distributions Rn are equal, and by this processing, the dimming level LV
is determined according to the number M of effective photometric areas and each reflectance distribution Rn (both are determined from the photometric signal of each photometric area). Specifically, each reflectance distribution R
The more n there are smaller than the average value, that is, the more there are regions where the reflectance distribution Rn is higher than other regions by a certain degree, and the larger the difference between those reflectance distributions, the smaller the dimming level LV is. Become. Further, this dimming level LV becomes smaller as the number M of effective photometry areas decreases.

Here, since each photometric signal BPn is corrected in step S13 above based on the area of each of the divided light receiving elements 13a to 13e, the number M of effective photometric areas depends on the area of the entire effective photometric area. From this, the fact that the dimming level LV is determined according to the size of the effective photometric area can be said to be determined according to the area of the effective photometric area.

Next, the process advances to step 81608, and it is determined whether or not the obtained dimming level LV is equal to or greater than a preset predetermined value (0.03 in this case). Dimming level LV with 51609
is set to 0.03 and the process proceeds to step 81610. this is,
When the light control level LV is less than a predetermined value, it is corrected so that it becomes a predetermined value or more, and this is a measure to prevent the light control level LV from being too low and causing underexposure. Note that the predetermined upper dividend value is not limited to 0.03.

In step 51610, the dimming level LV is converted to correspond to the ISO sensitivity (read in step S2) SV by LV=LV.2-"v-5'.

Thereafter, the process proceeds to step 517 (FIG. 7), in which a process is performed to calculate the weighting amount for correcting the photometric signal during the main flash, which will be performed later. In FIG. 12 showing the details of step 817, n=o is first set in step 5171, and then in steps 8172 to 5174, the weighting corresponding to each photometric signal is set to the amount Dn (obtained in step S14, 1 or O) to L (n) /S (
n) and the new weighting is the quantity. Here, L (
n) is the lens correction coefficient obtained in step S13, and S (n) is the area correction coefficient. That is, in this embodiment, the light level LV is adjusted according to the reflectance distribution Rn.
Since it is variable, there is no need to calculate the weighting amount according to the reflectance distribution, and therefore, here, the weighting amount is calculated only by the lens correction coefficient L (n) and the area correction coefficient S (n). . Further, the amount of weighting corresponding to the photometric signal excluded in step S14 is naturally zero.

Thereafter, the process proceeds to step 518 (FIG. 7), where the shutter 1 is
0 is opened, and when it is fully opened, the light emission control circuit 36
The electronic flash device 11 is caused to emit main light via the step S1.
In step 9, the light reflected from the film surface is measured in sections. That is, the illumination light from the main emission is reflected by the subject, transmitted through the photographic lens 2, and reflected by the film surface, and then received by the five light receiving elements 13a to 13e, and the output signals of the light receiving elements 13a to 13e are sent to the light control circuit. 40 amplifiers 41a to 41e (FIG. 6). Further, in step S20, the CPU 31 determines that each weighting obtained in step S17 is applied to the gain setter 42 of the dimming circuit 40 according to the amount Dn.
The amplification factors of the amplifiers 41a to 41e are set by a to 42e. That is, weighting is performed.

The amplifiers 41a to 41e amplify the output signals of the respective light receiving elements 13a to 13e at a set amplification factor and input the amplified signals to the adder circuit 44, which adds the input amplified signals. In step 821, an integral signal is output to the integrating circuit 45, and thereby the integrating circuit 45 integrates the addition result of the adding circuit 44 over time.

On the other hand, the dimming level LV calculated in step 816 is output to the conversion circuit 46, which converts it into an analog signal. The outputs of this conversion circuit 46 and the integration circuit 45 (which correspond to a predetermined dimming evaluation value) are input to a comparator 47, and when the output of the integration circuit 45 reaches the dimming level LV, the comparator 47 A light emission stop signal is input to the CPU 31. When this light emission stop signal is input, that is, when step S22 is affirmed, the CPU 31 controls the light emission control circuit 3 of the electronic flash device 11 in step 823.
6 to stop the main light emission, and then terminate the process.

According to the above procedure, an effective 24-photometry area is extracted in step S14 from the photometry signal from the preliminary flash, the aperture value, and the shooting distance, the reflectance distribution of the effective photometry area is determined in step 815, and the reflectance distribution of the effective photometry area is determined in step 816. The dimming level is determined according to the reflectance distribution and the number (area) of effective photometry areas. During the main light emission, the main light emission is stopped when the total value of the photometric signals reaches the above dimming level. Since the dimming level changes in accordance with the number (area) of effective photometric areas in this way, the following effects are achieved.

That is, when the number of effective photometry areas is small.

The total value of the photometric signals (output of the integrating circuit 45) during the main flash is relatively small compared to the case where there are many lights. For this reason, if the light control level is set to a constant value regardless of the number (area) of effective metering areas, the main subject is likely to be overexposed if there are few effective metering areas, and conversely, if there are many effective metering areas. It is easy to be underexposed. Therefore, as mentioned above, the smaller the number of effective metering areas, the lower the light control level, and the larger the number, the higher the light control level, thereby increasing the possibility that the main subject will be properly exposed in any case. It gets expensive.

In addition, in this embodiment, the light control level also changes depending on the reflectance distribution of each photometry area. For example, if the reflectance distribution of the photometry area that includes the main subject is higher than others (such (In such cases, the main subject is likely to be overexposed)
In this case, the light control level is lowered in accordance with the difference between them, which further increases the possibility that the main subject will be properly exposed. Further, when the determined light control level is less than or equal to a predetermined value, it is corrected to be equal to or greater than the predetermined value, so that underexposure due to the light control level being too low can be prevented.

In the configuration of the above embodiment, the electronic flash device 11 functions as the flash unit 101, the light receiving element 13a = 13e and the dimming circuit 40 function as the photometry unit 102, the CPU 31 functions as the level determining unit 103 and the level correcting unit 104, and the CPU 31 functions as the level determining unit 103 and the level correcting unit 104.
31 and the dimming circuit 40 constitute the dimming means 105, respectively.

Note that in the above example, when the determined dimming level is below a predetermined value, it is corrected to be equal to or greater than the predetermined value, but when the dimming level is equal to or greater than the predetermined value, it is corrected to be equal to or less than the predetermined value. is shown in FIG.

Figure 13 shows steps 51605 and 5160 in Figure 11.
6 is changed to steps 52001 and 52002, and steps 52003 and 52004 are added between steps 51607 and 51608. That is, if step 51604 is affirmed, step 52C)01 sets the dimming level LV to 0.025 (first
In Figure 1, the step is 0°02), and if the answer is negative, the dimming level is increased to 0.025XRn/M in step 52002.
Step forward by AX (R). According to this, the maximum value of the determined dimming level LV is 0.125.

Then, in step 52003, it is determined whether the dimming level LV is 0.1 or less, and if affirmative, the process proceeds to step 81608 described above, and if negative, step 52004
Correct the dimming level LV to 0.1.

According to the above procedure, the dimming level LV is 0.03 to 0.0.
It will be limited within the range of 1. Therefore, in addition to the same effect as described above, it is also possible to prevent overexposure due to the dimming level 7 being too high.

Note that in the above description, the dimming level Lv is changed, but the same effect can be obtained by changing the gain of the integrating circuit or the amplifier as appropriate instead. Therefore, the determination of the dimming level in this specification also includes changing the gain of such an integrating circuit or amplifier.

In addition, in the following, the dimming level LV is determined based on the reflectance distribution Rn of each photometric area and the number (area) of effective photometric areas, but the dimming level is determined only by the reflectance distribution or the number of areas. You can do it like this.

Furthermore, although the explanation has been made using a camera that performs preliminary light emission, the present invention can also be applied to a camera that does not perform preliminary light emission.

In this case, the dimming level is determined based on each photometric signal obtained at the initial stage of light emission (main light emission), and as described above, if this dimming level is outside the predetermined range, it is set within the predetermined range. The light emission is stopped when the dimming evaluation value calculated based on the photometric signals obtained after the initial stage of light emission reaches the light control level determined or corrected above. do it.

Furthermore, although the above description has been made with respect to a camera using a silver halide film, the present invention can be similarly applied to an electronic still camera that takes pictures using, for example, a floppy disk.

Effects of the G6 Invention According to the invention of claim 1, in a camera that performs preflash, the light control level is determined from the photometric signal obtained during the preflash, which eliminates the conventional light control level that was a constant value. Compared to this, there is a higher possibility that the main subject will be photographed with flash light at the correct exposure. In addition, if the determined dimming level is outside the predetermined range, it is corrected so that it falls within the predetermined range, so it is possible to further increase the possibility that the main subject will be properly exposed.

According to the second aspect of the invention, in a camera that does not perform preliminary flash, the light control level is determined from the photometry signal obtained at the initial stage of light emission, and when the determined light control level is outside a predetermined range, Since the correction is made so that it falls within the predetermined range, the same effect as described above can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a complaint correspondence diagram. 2 to 12 show an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of an automatic light control camera according to the present invention, and FIG. 3 is a perspective view showing a condensing lens array and a divided light receiving element. Figure 4 is a diagram showing the positional relationship between the divided light receiving elements and the film exposure area, Figure 5 is a block diagram of the control system, Figure 6 is a configuration diagram of the dimming circuit, and Figure 7 is the main flowchart. +-1 8th
12 is a flowchart showing a subroutine, and FIG. 13 is a flowchart showing a modification of FIG. 11. 8: Photometering element 9: Aperture 10: Shutter 11: Electronic flash device 12: Condensing lens array 13: Light receiving elements 13a to 13e: Divided light receiving element 31: CPU 32 Nielise button 36:
Light emission control circuit 101: Flashing means 103 Two-level determining means 104 Two-level correcting means 105: Light control means 40: Light control circuit 102: Photometry means

Claims (1)

[Claims] 1) main flash that emits light to take a flash photograph of the subject;
a flash means capable of preflashing light before the main flash; and dividing the object field into a plurality of areas, and photometering each reflected light from the plurality of areas due to the preliminary flash of the flash means and the main flash. and a level determining means that determines a dimming level based on each photometric signal at the time of the preliminary flash; and when the determined dimming level is outside a predetermined range set in advance. , a level correction means corrects the level so that it falls within a predetermined range, and a predetermined dimming evaluation value that is cumulatively calculated based on each of the photometric signals at the time of main emission, is adjusted to be within a predetermined range. A TTL automatic light control camera comprising: a light control means for stopping the main light emission when a light level is reached. 2) A flash unit that emits light to take a flash photograph of a subject, and dividing the subject into a plurality of areas and measuring each reflected light from the plurality of areas due to the light emission of the flash unit. a photometric means for outputting a signal; a level determining means for determining a dimming level based on each photometric signal at the initial stage of the light emission; and when the determined dimming level is outside a predetermined range set in advance. a level correction means for correcting the level to be within a predetermined range; and a predetermined dimming evaluation value that is cumulatively calculated based on each of the photometric signals after the initial stage of light emission is adjusted to be within a predetermined range. A TTL automatic light control camera comprising: a light control means for stopping the light emission when a light level is reached.