JPH03223822A - Camera - Google Patents

Abstract

PURPOSE:To easily discriminate both of a rear light state and a low brightness state by dividing a field into plural areas, obtaining a difference between the brightness of a specified area and maximum brightness in the plural areas and comparing a specified value which changes according to the value of the brightness of the specified area with the value of an error. CONSTITUTION:The field is divided into plural areas S01-S15 and the brightness of every divided area is detected by silicon diodes SPD01-SPD15 corresponding to the S01-S15. The difference between 1st brightness information of the specified area out of the plural areas and 2nd brightness information showing the maximum value in the plural areas is detected and the information of the obtained difference is compared with the specified value which changes according to the value of the 1st brightness information so as to decide the emission of flash light. Thus, both of the rear light and the low brightness are discriminated by a simple system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera that measures light by dividing a field into a plurality of small areas.

[Conventional technology]

Conventionally, various photometering devices have been proposed that divide the field of view into multiple regions, output brightness signals for each region, and use these multiple brightness signals to provide appropriate exposure to the photographic screen. ing.

For example, Japanese Utility Model Publication No. 51-9271 proposes a photometric device that uses, as a photometric value, the arithmetic average value of the maximum value and minimum value among the outputs from a plurality of photoelectric elements.

Furthermore, in Japanese Patent Publication No. 63-7330, photometry is performed by dividing the field into a central area and a plurality of outer areas that are divided into two or more areas and arranged to surround the central area. The brightness of each area is normalized using a reference value set between the maximum and minimum brightness values of the area, the subject is classified based on this normalized output, and the photometric value is calculated using the classified output. We are proposing a photometric device that performs calculations.

In the conventional example above, little consideration was given to the placement of the main subject within the shooting screen, but this one assumes that it will be installed in a camera equipped with an automatic focus detection device, and takes great consideration to the placement of the main subject within the shooting screen. has also been proposed.

For example, in Japanese Patent Application Laid-open No. 61-279829, the center of the screen is set as the position where the main subject is placed, and the field of view is divided into a plurality of areas including at least a plurality of concentric areas centered at the center of the screen. proposed a photometric device that could accurately determine the brightness of the main subject by selectively using the brightness signals of concentric areas based on the image magnification information and assuming the size of the main subject. There is. The same bulletin also proposes changing the formula for calculating photometric values by calculating the brightness of the background in addition to the brightness of the main subject, and using these differences in brightness. In addition, if the main subject is small, it is also possible to provide an appropriate exposure for the shooting situation.

Also, in Japanese Patent Application Laid-Open No. 62-184319, the center of the screen is set as a position where the main subject is likely to be placed, and the field of view is
The difference between the brightness signals of these multiple areas and the brightness signals between adjacent areas is calculated by dividing the screen into three areas: the area at the center of the screen, the area outside it, and the area further outside it. Based on this, the publication proposes a photometer that determines the approximate size of the main subject and the shooting situation at the same time to provide the appropriate exposure.The publication also proposes a photometer that determines the approximate size of the main subject using the difference in luminance signals. Compared to estimating the size of the main subject using the photographic magnification, it is less dependent on the actual size of the main subject, making it possible to stably obtain the correct exposure. There is an advantage.

In the two conventional examples cited here, the center of the screen was assumed to be a position where the main subject would be easily placed because the focus detection area of cameras equipped with automatic focus detection devices was generally set at the center of the screen. It is. On the other hand, recent automatic focus detection devices have been proposed that have multiple focus detection areas, and in cameras equipped with such automatic focus detection devices, each of the multiple focus detection devices has a The main subject is also likely to be placed in a specific area other than the central area.

Various photometric devices have been proposed that divide the field into multiple regions and calculate photometric values using various calculations, but relatively few devices have been proposed that accurately determine whether or not to fire a flash. few. As a device for detecting only a backlight condition, for example, Japanese Patent Application Laid-Open No. 1-280737 proposes a device that detects a backlight condition based on a luminance difference between predetermined areas.

[Problem to be solved by the invention]

With conventional multi-segment photometry cameras, backlighting can be easily determined by comparing the brightness of the central area and the surrounding areas, but low brightness can be determined using other detection methods, such as using the average metering value as a reference value. A method of comparison is required.

[Means to solve the problem]

a light receiving means that divides a field into a plurality of regions and detects the brightness of each divided region; first brightness information of a specific region among the plurality of regions; brightness difference detection means for detecting a difference between the brightness information and second brightness information indicating the maximum value of ,
The camera is characterized by having a light emission determining means for determining flash light emission, so that both backlight discrimination and low brightness discrimination can be performed in a simple manner.

〔Example〕

1 to 15 are diagrams showing a first embodiment of the present invention, and represent a camera equipped with three focus detection points.

FIG. 1 is a diagram showing the divided shape of the light-receiving surface of the photometric light-receiving section of the first embodiment of the present invention, and shows the state projected onto the field. In the same figure, SQL, 502...S L5
represents a plurality of divided light receiving small areas, SL.

So and SR represent the focus detection field of view projected onto the field of view, similar to the photometric light receiving section. In this example, as shown in Figure 1, the field of view is divided into a total of 15 small areas: 3 small areas containing 3 focus detection points and 12 surrounding small areas. The field brightness is photometered for each small area.

FIG. 2 is a diagram showing the optical arrangement of the first embodiment of the present invention,
In the figure, l is a photographing lens, 2 is a quick return mirror, 3 is a focusing plate, 4 is a penta roof prism, 5 is an imaging lens for photometry, 6 is a light receiving part for photometry, 7 is an eyepiece lens,
8 is a pupil position, 9 is a submirror 10 is a field mask, 11
12 is a condensing lens, 12 is a total reflection mirror, 13 is a pupil division mask, 14 is an imaging lens for focus detection, 15 is a light receiving section for focus detection, and 16 is a film surface. In this embodiment, the subject image formed on the focusing plate 3 by the photographing lens l is imaged on the photometric light receiving section 6 by the photometric imaging lens 5, and the 15 small images shown in FIG. Photometry is performed by dividing the image into areas, and the focus of a part of the subject image formed in the vicinity of the field mask 10 placed near the planned imaging plane of the photographic lens l is detected by the focus detection imaging lens 14. Light receiving section 15
An image is formed above to perform focus detection in an area corresponding to the three focus detection fields shown in FIG. FLA indicates built-in flash device.

FIG. 3 is an exploded perspective view of the focus detection optical system shown in FIG. The subject image formed in the vicinity of these three apertures is divided into two images each by the focus detection imaging lens 14, and the images are formed on the focus detection light receiving section 15 to focus on the three points in the photographic screen. Detection is in progress.

FIG. 4 is a block diagram showing the circuit configuration of the first embodiment of the present invention. In the same figure, S P Do+ , S
P D 02..., SPD, 5 are the 15 light receiving small areas SOI, 502..., S shown in FIG. 1, respectively.
This is a silicon photodiode (SPD) corresponding to L5, and generates a photocurrent according to the brightness of each small area. AMPo+.

A M P 02 ・= , A M P 15 and D
Io+, DI02. -, DI 15 is an operational amplifier and a compression diode, respectively, and a silicon photodiode (SPD), an operational amplifier, and a compression diode are combined to constitute light receiving means corresponding to the 15 light receiving small areas shown in FIG. ing. Figure 4 17 shows photometry circuit A
ECKT, which A/D converts the output signals corresponding to the brightness of a plurality of light receiving small areas and outputs them as digital signals. 18 is a flash mode selection switch F
LSW, whether or not there is a forced-flash mode in which the flash (built-in flash unit) is forcibly turned on according to the operator's will, and whether the camera should automatically shoot with the flash depending on the situation of the subject. Automatic detection mode that automatically fires the flash or recommends the use of the flash, and forcibly turns off the flash at the operator's will.
It is possible to select one of the following forced non-emission modes. 15 is a focus detection light receiving section corresponding to FIG. 3, and CCDLI and CCDL2. CCDo, and CCDc2
, and CCDRI and CCDR□ are the focus detection field of view SL in FIG. 1, respectively.

There are three pairs of light receiving element arrays corresponding to Sc and SR. The pair of light-receiving element arrays uses the optical system shown in FIGS. 2 and 3 to detect two different types of field light on the exit pupil plane of the photographic lens, out of the field light that forms an image on a predetermined area of the photographic screen. It is configured so that only the light flux that has passed through one area is extracted and formed into an image, and the amount of defocus can be detected by comparing the output signals from these pair of light receiving element arrays. 19
is the focus detection circuit AFCKT, and the focus detection light receiving section 15
Based on the output signals from the three pairs of light-receiving element arrays provided in the
L.

The defocus amounts of the field corresponding to So and SR are detected, and information on the three defocus amounts is output as a digital signal. 20 is a focus detection point selection switch A
FSW, depending on the operator's will, the camera automatically selects the appropriate shooting screen according to the distribution of the amount of defocus in the field corresponding to the three focus detection fields of view SL, Sc, and SR in Figure 1. automatic selection mode that determines the focus position, and
It enables the operator to select one of the optional selection modes for selectively determining the focus detection field of any one of the three focus detection fields of view in the figure, and furthermore, in the optional selection mode, this focus detection point It is configured such that the focus detection point to be selected can be indicated by a selection switch. In FIG. 4, a photometric circuit AECKT17, a flash mode selection switch FLSW18, a focus detection circuit AFCKT19,
The input signal from the focus detection point selection switch AFSW20 is connected to the internal data bus line BUS of the microcomputer.
21 and is used for various controls.

In FIG. 4, reference numeral 22 denotes a central processing unit J that processes the various input signals mentioned above and instructs the operation of various control mechanisms using programs stored in various memories.
cPU, 23 is a read-only memory ROM that stores various programs, 24 is a random access memory RAM as a work area for calculations, 25 is a display control mechanism DPCNTL, 26 is a shutter time control mechanism 5TC
NTL, 27 is a flash control mechanism FLCNTL, 28
are general-purpose input/output ports P.sub.0, each connected to the internal data bus line BUS21 of the microcomputer.

The CPU uses the above-mentioned input signals to execute calculations according to the program stored in the ROM by accessing the RAM, and based on the calculation results, the DPCNTL 25
．． 5TCNTL26 and FLCNTL27 control the display and shutter flash, and output a signal for controlling the lens to PI028.

FIG. 4 29 shows a connector CNCT, which performs communication between the camera and the lens. 30 is a read-only memory LROM that stores information unique to the photographic lens; 31 is a focal position control mechanism AFCNTL for the photographic lens; and 32 is an aperture control mechanism APCNTL for the photographic lens.

LROM30 and AFCNTL included in the photographic lens
, 31, is connected to the camera's PIO 28 via the APCNTL 32 and CNCT 29, and is connected to the camera's CPU 22.
The reading or control mechanism is configured to be read out or to operate the control mechanism according to the instructions of the controller.

In this embodiment, as explained above, the photometry circuit AE
CKT17, flash mode selection switch FLSW1
8. Based on the input signals from the focus detection circuit AFCKT19 and the focus detection point selection switch AFSW20, the microcomputer is used to adjust the focus position of the camera's display device, shutter, flash, and photographic lens, and control the aperture. There is.

Next, the software configuration of the first embodiment of the present invention will be explained.

5 to 11 are flowcharts showing the software configuration of the first embodiment of the present invention, with FIG. 5 showing the main routine and FIGS. 6 to 11 showing each subroutine.

First, the main routine shown in FIG. 5 will be explained.

5 TEPOI: In the main routine camera, information corresponding to the brightness of the subject, information on the defocus amount of each of multiple focus detection points set in advance, flash mode selection information based on the photographer's will, and focus detection Control of focus position adjustment using point selection information and exposure control using shutter speed and aperture settings,
Handles flash control and display control. There are other items that the main routine should handle, such as quick return mirror drive control and film feeding mechanism control.
Here, only items related to the photometry device and flash photography control device of the camera of the present invention are taken out, and other items are omitted for the sake of simplicity.

5TEPO2: Take in signals of defocus amount of three focus detection points from AFCKT19. The amount of defocus is determined by a pair of line sensors, CCDL and CCDL2, and CCDC1 and CCDC2, corresponding to each focus detection point.
It is calculated by detecting the amount of deviation between the output signals of CCDR, CCDR, and CCDR□, and is captured as a digital signal.

5TEPO3: Takes in the focus detection point selection signal from AFSW20 and the defocus amount signal from AFCKT19, and when the photographer selects one focus detection point among the three focus detection points, the focus detection point is detected. If a signal corresponding to the fish is output and the photographer automatically selects the focus detection point by the camera, the focus detection point closest to the subject distance is detected from the three defocus m signals, and the focus detection point is selected from the three defocus m signals. This is a focus detection point selection subroutine that outputs a signal corresponding to the focus detection point signal SEL.

5TEPO4: The defocus amount to be adjusted is determined from the defocus amount signals of the three focus detection points and the above-mentioned focus detection point signal SEL, and the focus of the photographing lens is adjusted by the AFCNTL30.

5TEPO5: Take in signals corresponding to the brightness of 15 small areas and a digital signal from AECKT17.

5TEPQ6: Corrects the signal taken in from AECKT17 as appropriate based on information specific to the photographic lens taken in from LROM29, outputs a brightness signal of the object field corresponding to each small area, and further outputs a brightness signal of the object field corresponding to each small area. Based on the above-mentioned focus detection point signal SEL, a brightness signal A of the middle area including the focus detection point, a brightness signal B of the surrounding middle area, and a brightness signal C of the middle area surrounding the focus detection point are determined. This is a subroutine that calculates the maximum value MAX of the brightness signals of 15 small areas, and the four brightness signals A described above.

Output B, C, MAX.

5TEPO7: A flash that takes in the input signal from the FLSW 18, determines whether or not flash photography should be performed based on the photographer's will or the camera's judgment of the subject situation, and outputs a signal FLSH indicating whether or not flash photography is to be performed. This is a shooting setting subroutine. The method of determining the scene situation using the camera will be described later.

5TEPO8: This is a photometric value calculation subroutine that inputs the brightness signals A, B, and C and the output signal FLSH of the flash photography setting subroutine, and outputs the photometric value E during natural light photography and flash photography.

5TEPO9: Determines the shutter speed and aperture value from the photometric value E based on the program preset in the camera, and outputs it.In addition to program mode, shutter priority mode, aperture priority mode, etc. It may also be possible to switch the shooting mode, and in either case, the shutter speed and aperture value are determined here based on those programs.

5TEPIO: The DPCNTL 25 displays exposure information such as shutter speed and aperture value, as well as focus detection point selection information, photometry mode selection information, flash use recommendation information, etc., on the display device of the camera as necessary.

S'FEPII: Based on the shutter speed and aperture value determined as described above, the shutter speed is controlled by 5TCNTL 26, the aperture of the photographing lens is controlled by APCNTL, and the flash FLA is controlled by FLCNTL.

In steps 5TEPO2 to 5TEPII, the camera completes a series of shooting operations, and in order to prepare for the next shooting operation,
Return to TEPO2 state.

Next, each subroutine will be explained.

FIG. 6 is a flow chart showing the STE I) 03 focus detection point selection subroutine of FIG.

5TEP21, focus detection point selection subroutine 5TEP
22: Import focus detection point selection information from the AFSW 20. A FSW outputs the focus detection point selection signal AUTO when the photographer sets the focus detection point to be automatically selected by the camera, and outputs the focus detection point selection signal AUTO when the photographer sets one focus detection point selectively. Here, when the focus detection point SL located on the left side of the photographing screen is selected, the focus detection point selection signal FL is output, and when the focus detection point Sc located at the center of the photographing screen is selected, the focus detection point selection signal is output. When the focus detection point SR located on the right side of the photographic screen is selected by outputting FC, a focus detection point selection signal FR is output.

5TEP23: Determine whether the focus detection point selection signal is AUTO. 5TEP2 if AUTO
Proceed to 4, and if it is not AUTO, proceed to 5TEP25.

5TEP24: When the focus detection point selection signal is AUTO, the three focus detection points SL+SC+SR are selected using the defocus amount signal output from AFCKT19.
Among them, the focus detection point with the closest subject distance is identified, and a signal Nearest (F
L, FC, FR).

5TEP25: Determine the focus detection point signal SEL in accordance with the focus detection point determined by selection by the photographer or automatic selection by the camera. The focus detection point signal SEL is F
Outputs one of L, FC, and FR.

5TEP26: Return to the main routine.

FIG. 7 is a flowchart showing the 5TEPO6 area brightness calculation subroutine of FIG.

S, TEP31: Photometric value calculation subroutine.

5TEP32: Digital signals Dol, D corresponding to the brightness of 15 small areas output from AECKT17
02.

D03,..., D,5 is taken in.

5TEP33: Retrieve information specific to the attached photographic lens from LROM33. The information unique to the photographic lens includes information such as the aperture F number of the photographic lens, focal length, exit pupil position, and peripheral light falloff when the aperture is fully open.

5TEP34: Using information specific to the photographic lens, perform AEC
Correction data δ01. which corrects each of the 15 output signals from KT. δ02. ..., δ15 is determined, and a luminance signal for each small area is calculated. That is, the luminance signal vow
, VO2, . . . VI5 are determined from the following formula and output. Note that the correction data δ01. δ02° . . . , δ15 are selected and determined from a table stored in advance in the ROM 23 based on the above-mentioned information specific to the photographing lens. It is also possible to calculate by calculation.

5TEP35: Determine whether the focus detection point signal SEL is the signal FL representing the focus detection point on the left side of the photographic screen. If 5EL=FL, proceed to 5TEP37 SEL≠F
If it is L, proceed to 5TEP36.

5TEP36: Determine whether the focus detection point signal SEL is a signal FC representing the focus detection point at the center of the photographic screen. 5
If EL=FC, proceed to 5TEP38, SEL≠FC
If so, proceed to 5TEP39.

Classification is performed according to the focus detection point using 5TEP35 and 5TEP36, and when the focus detection point is on the left side, 5TEP35 and 5TEP36 are used.
Proceed to P37, and if the focus detection point is at the center, 5TEP38
In other cases, that is, when the focus detection point is on the right side, the process proceeds to 5TEP39.

5TEP37 to 5TEP39 classify the 15 classified small areas into three medium areas: the area near the focus detection point, the area around it, and the peripheral area around it, and calculate the average brightness of each medium area. It is calculated and output. At this time, 1
The five small areas are classified so that they are always included in one of the medium areas. The average brightness signal of each middle area is output as A, the average brightness signal of the area near the focus detection point as A, the average brightness signal of the surrounding area as B, and the average brightness signal of the surrounding area as C. .

5TEP37: Determine the classification of the middle area when the left focus detection point is selected, and calculate the average brightness signals A and B of each middle area.
, C is output based on the following equation.

A = V 07 B = (VO2+VO6+VO8+V, 2)/4C=
(V01+V03+V04+VO5+Vl)9+V
16+V,, +V, 3+V,, +V, 5)
/10 STEP 38: Determine the classification of the middle area when the central focus detection point is selected, and output the average luminance signals A, B, and C of each middle area based on the following equation.

A = V as B= (VO3+VO7+VO9+VH3)/4C==
(V01+V02+VO4+VO5+VO6+VI.

+V,, +V, 2+V, 4+V, 5) /1
0STEP39: Determine the classification of the middle area when the right focus detection point is selected, and calculate the average brightness signal A of each middle area,
B and C are output based on the following equations.

A=VO9 B= (Vo4+Vos+V, o+V, 4) /4
C= (V01+V02+V03+VO5+VO6+V
O70V,, +V l□+V, 3+V, 5)
/10STEP40: Luminance signal output from 15 small luminances (D maximum value Max (Vat, VO2, V
O3, -r V 15 ) is selectively determined and output as the maximum luminance signal MAX.

5TEP41: Return to the main routine.

As explained above, in the area brightness calculation subroutine, the area brightness signals A, B, C and the maximum brightness signal MAX are calculated and output.

FIG. 8 is a flowchart showing the flash photography setting subroutine of 5TEPO7 in FIG.

5TEP51: Flash photography setting subroutine.

5TEP52: Retrieve flash photography setting information from FLSW18. FLSW outputs a flash photography setting signal ON when the photographer sets to forcibly perform flash photography.
If the photographer sets the camera to automatically determine whether or not to perform flash photography, the flash photography setting signal AU
TO is output, and when the photographer forcibly sets not to perform flash photography, a flash photography setting signal OFF is output.

5TEP53: If the flash photography setting signal is ON, proceed to 5TEP55; otherwise, proceed to AUTOl
Or if it is OFF, proceed to 5TEP54.

5TEP54: If the flash photography setting signal is AUTO, proceed to 5TEP56; otherwise, proceed to 0
In the case of FF, proceed to 5TEP57.

5TEP53.5TEP54, the input signal from the FLSW is classified into three types: ON, AUTO, and OFF.

5TEP55: When the input signal from FLSW is ON, the flash setting signal FLSH is output as FLON.

5TEP56: This is a flash photography condition determination subroutine that determines whether or not flash photography should be performed depending on the luminance distribution of the subject when the input signal from the FLSW is AUTO. The flash photography condition determination subroutine receives the area brightness signal A and the maximum brightness signal MAX among the brightness signals output from the area brightness calculation subroutine of 5TEPO6 in FIG. When it is determined that it is necessary to perform the flash setting signal F
LSH is output as FLON, and when it is determined that flash photography should not be performed, the flash setting signal FLSH is output as FLO.
Output as FF.

5TEP57: When the input signal from FLSW is OFF, outputs the flash setting signal FLSH as FLOFF.

5TEP55 to 5TEP57 output the flash setting signal FLSH as FLON when flash photography should be performed, and output the flash setting signal FLSH as FLOFF when flash photography should not be performed.

5TEP58: Return to main routine.

FIG. 9 is a flowchart showing the 5TEP56 flash photography condition determination subroutine of FIG.

5TEP61: Flash photography condition determination subroutine.

5TEP62: Of the output signals of the area brightness calculation subroutine of 5TEPO6 in FIG. 5, the area brightness signal A and the maximum brightness signal MAX are input, and their brightness difference signal DE is
Calculate LTA using the following formula.

DELTA=MAX-A STEP 59: A predetermined brightness signal RL set to the low brightness side (here, it is determined whether the situation is outdoors or indoors) is sent to the brightness signal in the middle area including the focus detection point. The approximate brightness of the main subject is recognized by comparing it with the brightness of the main subject.

When A>RL, that is, when it is determined that the situation is outdoors, the process proceeds to 5TEP63, and when A≦RL, that is, when it is judged that the situation is indoors, the process proceeds to 5TEP66.

5TEP63: Brightness signal A in the middle area including the focus detection point is further converted to a predetermined brightness signal RH set on the high brightness side (here, when the main subject is outdoors and is placed in the sun or in the shade) The value should be sufficient to identify whether the

), the approximate brightness of the main subject placed outdoors can be recognized in more detail. When A>RH, that is, when it is determined that the situation is outdoors in the sun, the process proceeds to 5TEP65, and when A≦RH (therefore, when RL<A≦RH), that is, the situation is outdoors in the shade. 5TE when it is determined that
Proceed to P64.

5TEP64: Compare the luminance difference signal DELTA with a first predetermined value rL for determining whether or not there is a backlight condition. When DELTA<rL, it is determined that there is no backlight condition, and the process proceeds to 5TEP68. When DELTA≧rL, it is determined that there is a backlight condition, and the process proceeds to 5TEP67.

5TEP65: Compare the luminance difference signal DELTA with a second predetermined value rH for determining whether or not there is a backlight condition. When DELTA<rH, it is determined that there is no backlight condition, and the process proceeds to 5TEP70. When DELTA≧rH, it is determined that there is a backlight condition, and the process proceeds to 5TEP69.

Using 5TEP63 to 5TEP65, the following five classifications are used to determine whether the main object scene is in a low-luminance state or in a backlit state.

A≦RL; low brightness 5TEP66:
In the case of low brightness mentioned above. It is determined that flash photography should be performed, and the flash setting signal FLSH is output as FLON.

5TEP67: In the above-mentioned case of slightly high brightness or backlight, it is determined that flash photography should be performed and the flash setting signal FLSH is set to FLO.
Output as N.

5TEP68: In the above-mentioned case of slightly high brightness and front light, it is determined that flash photography should not be performed, and the flash setting signal F L is determined.
Output SH as F L OF F.

5TEP69: In the case of high brightness and backlight mentioned above, it is determined that flash photography should be performed, and the flash setting signal FLSH is set to FL.
Output as ON.

5TEP70: In the above-mentioned case of high brightness and order, it is determined that flash photography should not be performed, and the flash setting signal FLSH is set to F.
Output as LOFF.

As explained above, in 5TEP66 to 5TEP7o,
It is determined whether flash photography should be performed or not according to the situation of the scene classified by 5TEP63 to 5TEP65, and a flash setting signal FLSH is determined and output.

5TEP71: Return to flash photography setting subroutine.

FIG. 12 shows a method for determining the flash photography conditions described above. In FIG. 12, one coordinate axis is the luminance difference signal DELTA.

The other signal is used as an area brightness signal A to identify the brightness distribution state of the object field. As described above, in this embodiment, flash photography is performed in the shaded area in FIG. 12, and natural light photography is performed in the non-shaded area. A method of determining the photographing situation based on the figure will be explained below.

(a) A≦RL (STEP 66) This is a case where the brightness signal A in the middle area including the focus detection point is smaller than the predetermined value RL set on the low brightness side, and it is determined that the main subject is placed indoors. . In such a case,
The illumination light that illuminates the subject often has a different color temperature from outdoor natural light, such as fluorescent lights, and if natural light photography is done using this illumination light, the photograph will be reproduced with extremely unnatural colors. A problem arises. Therefore, in such a case, it is better to correct the color temperature by emitting flash light.

(b) RL<A≦RH, rL≦DELTA (ST
EP67) The brightness signal A in the middle area including the focus detection point is larger than the predetermined value RL set on the low-brightness side and smaller than the predetermined value RH set on the high-brightness side, and the brightness difference signal DE
This is the case when LTA is larger than the predetermined value r1-. In such a case, the main subject is placed outdoors in the shade, and there is a large difference in brightness from the background, so it can be determined that the scene is a typical backlit scene. When you take natural light photos with backlight like this,
If you try to give the entire screen an average exposure, the main subject will be considerably underexposed, and if you try to give the main subject a suitable exposure, the background will be considerably overexposed. Therefore, it is difficult to simultaneously give a somewhat suitable exposure to the main subject and the background. Therefore, in such a case, it is preferable to perform so-called daytime synchronized photography in which the main subject is illuminated with flash light and the background area that the flash illumination does not reach is photographed with natural light.

Here, the brightness difference signal DELTA is the difference between the maximum value MAX of the brightness signals of the 15 small areas and the brightness signal A of the small area including the focus detection point. The maximum brightness signal MAX extracts the brightness signal of a high-brightness subject such as the sky, clouds, or the sun placed within the shooting screen, and the area brightness signal A changes the area in conjunction with the selection of the focus detection point. Since the brightness of the main subject and its vicinity are extracted by , by using these differences, it is possible to relatively accurately determine whether the scene is a backlit scene.

(c) RL<Δ≦RH, DELTA<r L (ST
EP68) The brightness signal A in the middle area including the focus detection point is larger than the predetermined value RL set on the low brightness side and smaller than the predetermined value RH set on the high brightness side (, brightness difference signal DE
This is the case when LTA is smaller than the predetermined value rL. In such a case, the main subject is placed outdoors in the shade, there are almost no high-luminance subjects such as the sky or clouds in the photographic screen, and there is relatively little variation in the luminance signal. In such a case, it is best not to use a flash, since good exposure can be obtained by natural light photography.

(d) R1(<A, rH≦DELTA (STEP
69) The brightness signal A in the middle area including the focus detection point is thicker than the predetermined value RH set on the high brightness side (the brightness difference signal DEL
This is a case where TA is larger than the predetermined value rH, which is slightly smaller than the above-mentioned predetermined value rL. In such cases, the main subject is placed outdoors in the sun, and a subject with extremely high brightness such as sunlight or its reflected light is placed in the background, or a backlit scene with the sky or clouds in the background. Here, it is assumed that the main subject is somewhat small and the luminance signal A of the area including the focus detection point is already slightly influenced by the background and outputs a signal with a slightly higher luminance than the luminance of the main subject. Therefore, in such a case, flash light is emitted as in case (b),
It is best to use synchronized photography during the day.

Note that here, the predetermined values rH and rL for determining whether the scene is a backlit scene or not are such that rH<rl-. In general, when a scene is determined to be a backlit scene, a high-brightness sky or clouds are placed in the background, but the brightness is set at a predetermined brightness (Bv
8), and therefore the brightness difference DELTA will be large in backlit scenes when the main subject's brightness is lower than the predetermined value RH, and in backlit scenes when the main subject's brightness is higher than the predetermined value RH. In this case, a case may occur in which the luminance difference DELTA does not become very large.

Also, assuming a backlit scene with the same brightness difference between the main subject and the background, if the main subject becomes slightly smaller, the brightness signal of the area including the focus detection point will be
It is influenced not only by the brightness of the main subject but also by the brightness of the background, and as a result, the area brightness signal A tends to become high and the brightness difference signal DELTA tends to become small.

Considering the phenomenon explained above, the predetermined value for determining whether or not it is a backlit scene is the predetermined value r on the high brightness side.
H and a predetermined value r1- on the low luminance side are configured to have a relationship of rH<rL.

(e) RH<II, DELTA>r H (when the brightness signal A in the middle region including the 4C detection point is larger than the predetermined value RH set on the high brightness side, and the brightness difference signal DELTA is smaller than the predetermined value rH) In such a case, the main subject is placed outdoors in the sun, and the shooting screen is almost uniformly high brightness.In such a case, the same as in case (c) , it is best not to use a flash because good exposure can be obtained with natural light photography.

In this embodiment, as explained above, the situation of the scene is classified into five cases, and it is determined whether or not to emit flash light.

FIG. 1O is a flowchart showing the 5TEPO8 photometric value calculation subroutine of FIG.

5TEP81: Photometric value calculation subroutine.

5TEP82: Determine whether the flash setting signal FLSH is FLoN. 5 when FLSH=FLON
Proceed to TEP86, FLSH≠FLON, that is, FLSH
= FLOFF, proceed to 5TEP83.

5TEP83: Since the natural light photography mode has been selected, evaluate light metering is calculated. 5TEP37-5TEP39
Average brightness signal A in the middle area near the focus detection point obtained by
1. Using all of the average brightness signal B of the medium area around it, and the average brightness signal C of the medium area around it, weighting of approximately the entire screen is performed with a high emphasis on the vicinity of the focus detection point. Average luminance signal E. is calculated from the following formula.

E o = (A+B+C)/3 In the above formula, the three medium area brightness signals A, B, and C are simply added and averaged, but the area of the medium area near the focus detection point is S (A), The area of the middle region around it is S
(B), and further define the area of the middle region around it as S (
C), the area ratio of the three middle regions is 5(A):5(
Since E):5(C)=lH4:IQ, by performing this calculation, the average luminance is calculated by weighting with a higher degree of emphasis near the focus detection point. At this time, the importance of the three medium areas A, B, and C J (A), J (B)
, J (C) is proportional to the reciprocal of the area ratio, J (A)・J (B) : J (C) = 1: 0
．． 25: o, t. In the following explanation, E in the above equation will be used. The calculation for determining the value is called "focus detection point weighted average photometry."

5TEPI'84: Area brightness calculation subroutine 5TE
This is a correction value selection subroutine that uses the average brightness signal of the middle region obtained in PO6 and the difference between these average brightness signals to infer the shooting situation and selectively determines the exposure correction value α. Details will be described later.

5TEP85: The above-mentioned focus detection point weighted average photometry E.

Then, automatic exposure correction is performed by adding the exposure correction value α output from the correction value selection subroutine, and the photometric value E is determined by the following equation.

E=E o+α The photometric value E obtained by 5TEP83 to 5TEP85 is the photometric value obtained by evaluation photometry in this embodiment.

5TEP86: Since the flash photography mode has been selected in 5TEP82, photometric value calculation for flash photography is performed.

During flash photography, the main subject can be illuminated with a flash and adjusted to a suitable exposure level, so it is desirable to control the background so as to give a suitable exposure.

Therefore, in this embodiment, the area brightness calculation subroutine 5TE
By using the area brightness signals B and C output from PO6, a photometric value is determined by the following equation in order to give suitable exposure to the background area other than the main subject area.

E=(B+C)/2 In this embodiment, during flash photography, the photometric value is determined using the luminance signal of the surrounding area other than the area near the focus detection point selected as shown in the above equation.

It is assumed that the exposure is controlled using the above formula even in flash photography at low brightness, but in general, in the case of low brightness, AE calculations that do not make the shutter time too long are used to prevent camera shake, etc. is often performed using 5TEPO9 in FIG. 5, in which case the exposure is determined by another calculation and the above equation is not used.

5TEP87: Return to main routine.

As explained above, the photometric value calculation subroutine enables photometric value calculation that provides appropriate exposure for the main subject, the entire screen, or the background area, in conjunction with the selection of the focus detection point, both during natural light photography and flash photography. There is.

FIG. 11 is a flowchart representing the 5TEP84 correction value selection subroutine of FIG. 1O.

5TEPIOI: Correction value selection subroutine.

5TEI'102: Using the average brightness signal A of the middle area near the focus detection point, the average brightness signal B of the surrounding middle area, and the average brightness signal C of the surrounding middle area, Difference between luminance signals A and B and B and C, ΔBA
and ΔCB are calculated from the following equation.

Δl3A=13-A ΔCB=-B STEP 103: Convert the average luminance signal C of the surrounding medium area to a signal K corresponding to a predetermined luminance (here, a signal K that identifies whether the situation is outdoors or indoors) The approximate brightness of the scene is recognized by comparing the brightness of the subject. The reason why the average luminance signal C of the surrounding medium area is used here is that it is hardly affected by the reflectance of the main subject and is most suitable for estimating the situation in which the main subject is placed. When C≧, that is, when it is determined that the situation is outdoors, 5TE
The process advances to P104, and when C<K, that is, when it is determined that the situation is indoors, the process advances to 5TEP121.

5TEP104: When the average brightness of the surrounding medium area is higher than a predetermined value and it is determined that the scene is an outdoor scene, first,
The brightness difference ΔEA is compared with a predetermined value PH1 having a positive sign. If ΔBA<PH, proceed to 5TEP105 and ΔB
If A≧PH1, proceed to 5TEP106.

5TEP105: If ΔBA<PH, further set ΔBA to a predetermined value P with a negative sign. Compare with 2.

ΔBA<P. In case of 2, proceed to 5TEPIIO and ΔBA
If ≧PH2, that is, PH□≦ΔBA<PH, the process advances to 5TEP108.

Brightness difference ΔBA due to 5TEP104.5TEP105
are classified into the following three types.

PH1≦ΔBA; ΔBA is a positive value with a large absolute value; PH2≦ΔBA<PH,; ΔBA is a small absolute value.

ΔBA<PH2; ΔBA is a negative value with a large absolute value.

5TEP106: If P H1≦ΔBA, further compare ΔCB with a predetermined value QHI having a positive sign. ΔC
If B〈Q 111, proceed to 5TEP107 and ΔCB
If ≧QHI, proceed to 5TEpH2.

5TEP107: If ΔCB<Q Hl, further compare 8CB with a predetermined value Q)+2 having a negative sign.

If ΔCB<QH2, proceed to 5TEpH4, 8CB≧
If Ql(2, that is, QH2≦ΔCB<QHI, proceed to 5TEP113.

5TEr'106.5TEP107, C to luminance difference
B is classified into the following three types.

Q, 41≦ΔCB; ΔCB is a positive value with a large absolute value QH□≦ΔCB<QHI; ΔCB has a small absolute value.

ΔCB<QH2; ΔCB is a negative value with a large absolute value.

5TEP10B + PH If H2≦ΔBA<PM, ΔCB is further compared with a predetermined value QH+ having a positive sign. If ΔCB<QHI, proceed to 5TEP115,
If CB≧Q, 41, proceed to 5TEP109.

5TEP109: If ΔCB<QHI, further increase Δ
CB is compared with a predetermined value QH□ having a negative sign.

If ΔCB<QH2, proceed to 5TEP117 and check ΔCB
If ≧QH2, that is, if Q)+2≦80B<QHI, the process proceeds to 5TEP116.

Brightness difference ΔCB due to 5TEPI08.5TEP109
are classified into the same three ways as in 5TEP106.5TEP107.

5TEPIIO: If ΔBA<P, 42, further ΔC
B is compared with a predetermined value Q)I+ having a positive sign. 80B
If <QHI, proceed to 5TEP11B, ΔCB≧Q,
If it is 1, proceed to 5TEPIII.

5TEPIII: If ΔCB<QHI, further Δ
CB is compared with a predetermined value QH2 having a negative sign.

If ΔCB × QH□, proceed to 5TEP120 and ΔCB
In the case of ≧QH2, that is, in the case of QH2≦ΔCB<QH, the process advances to 5TEP119.

Brightness difference ΔCB due to 5TEPIIO1STEPIII
are classified into the same three ways as in 5TEP106.5TEP107.

When 5TEP103 determines that it is an outdoor scene, 5TEP104 to 5TEPI
II, the situation of the photographic scene is classified into nine types and the exposure correction value α is selected.

5TEP112 to 5TEP120: 5TEP104
Exposure correction values α suitable for the scene conditions classified by ~5TEPIII are respectively output. In this example, there are only three values of α: αM+, αH2, and 0 (however, α
H1 × αH2 < 0), and among these three values,
Select one of them. A method for determining the exposure correction value α will be described later.

5TEr'121 When the average brightness of the surrounding middle area is lower than a predetermined value and it is determined that the scene is an indoor scene, first, the brightness difference ΔBA is compared with a predetermined value PLI having a positive sign. If ΔBA<PL, proceed to 5TEP122,
If BA≧PLI, proceed to 5TEP123.

5TEP122: If ΔBA<PL, further increase Δ
BA is compared with a predetermined value PL2 having a negative sign.

If ΔBA<PL2, proceed to 5TEP127 and set ΔBA
In the case of ≧PL2, that is, in the case of PL2≦ΔBA<PL, the process proceeds to 5TEP125.

With 5TEP121.5TEP122, the brightness difference ΔBA
are classified into the following three types.

PLI ≦ΔBA: ΔBA is a positive value with a large absolute value.

PL2≦ΔBA<PL,; ΔBA has a small absolute value.

ΔBA<PL2; ΔBA is a negative value with a large absolute value.

5TEP123: If P L, ≦ΔBA, further ΔC
B is compared with a predetermined value QL+ having a positive sign. In the case of 8 CB × QLl, proceed to 5TEP124, ΔCB≧QLI
If so, proceed to 5TEP129.

5TEP124: If ΔCB<QLI, further increase Δ
CB is compared with a predetermined value QL2 having a negative sign.

If ΔCB<QL2, proceed to 5TEP131 and check ΔCB
If ≧QL2, that is, if QL2≦ΔCB<QLI, proceed to 5TEPI30.

Brightness difference ΔCB due to 5TEP123.5TEP124
are classified into the following three types.

QLI ≦ΔCB, ΔCB is a positive value with a large absolute value.

QL2≦ΔCB<QLI; ΔCO has a small absolute value.

ΔCB<Q L2; ΔCB is a negative value with a large absolute value.

5TEP125: If P L2≦ΔBA<PL,
Furthermore, ΔCB is compared with a predetermined value QL+ having a positive sign. If ΔCB<QLI, proceed to 5TEP126 and check ΔC
If B≧QL+, proceed to 5TEP132.

5TEP126: If ΔCB<QLI, further Δ
CB is compared with a predetermined value QL2 having a negative sign.

If ΔCB<QL2, proceed to 5TEP134 and check ΔCB
In the case of ≧QL2, that is, in the case of QL2≦ΔCB<QLI, the process proceeds to 5TEP133.

Brightness difference ΔCB due to 5TEP125.5TEP126
are classified into the same three ways as in 5TEP132.5TEP124.

5TEP127: If ΔBA<PL2, further ΔCB
is compared with a predetermined value QLI having a positive sign. ΔCB<Q
If LI, proceed to 5TEP128; if ΔCB≧QLI, proceed to 5TEP135.

5TEP128: If ΔCB<QLI, in addition, Δ
CB is compared with a predetermined value QL2 having a negative sign.

If ΔCB<QL2, proceed to 5TEP137 and check ΔCB
In the case of ≧QL2, that is, in the case of QL2≦ΔCB<QLI, the process proceeds to 5TEP136.

5TEP127.5TEP128, brightness difference ΔCB
are classified into the same three ways as in 5TEP123 and 5TEP124.

When 5TEP103 determines that the scene is an indoor scene, as explained above, 5TEP121 to 5TEP1
28, the situation of the photographic scene is classified into nine types and the exposure correction value α is selected.

5TEP129-5TEP137: 5TEP121
- Output each exposure correction value α suitable for the scene situation classified by the TEP 128. In this example, there are only three values of α: αLINαL2 and 0 (however, α
L1<O<α5□), and among these three values,
Select one of them. A method for determining the exposure correction value α will be described later.

5TEP138: Return to photometric value calculation subroutine.

In the correction value selection subroutine, as explained above, the situation of the object scene is estimated and an appropriate correction value α is output.

Next, a method for determining the exposure correction value α will be explained.

5TEP112 to 5TEP120 and 5T in Figure 11
ΔBA represents the 18 states classified into EP129 to 5TEP137.

When expressed in the coordinate plane with ΔCI3 as the axis of both seats, the 13th
The result will be as shown in Figures (a) and (b). In addition, 5TEP112 to 5TEP120 and 5TEP129 in FIG.
The state of ~5TEP137 is the brightness signal A of each medium area,
If B and C are shown in bar graphs, they will be as shown in Fig. 14 (a) and (b). FIG. 14 shows the focus detection point weighted average photometric value E in each situation. , the exposure correction value α, and the evaluation photometric value E are also schematically shown. Figures 13 and 14
The situation of the field under each condition and the method for determining the exposure correction value α will be explained below with reference to the drawings.

(a) When K≦C: Outdoor scene (a-i) PH
1<ΔBA1QHI×ΔCB (STEP 112) As shown in FIG. 13(a), ΔBA is a positive predetermined value P.
This is a case where ΔCB is larger than H1 and larger than a positive predetermined value QH+, and the brightness distribution is as shown in (i) of FIG. 14(a). In this case, the background part is high brightness and the main subject part is relatively low brightness.
-It can be assumed that this is a backlit scene while fishing on a boat. Moreover, since the brightness signal A1, brightness signal B1, and brightness signal C change in stages, the main subject placed near the focus detection point is located in the area where the brightness signal A is output and the area where the brightness signal B is output. It is thought that it exists across departments. In the case of such a brightness distribution, the focus detection point weighted average photometric value Eo will be output as shown in the figure. In order to give the exposure, it is best to use the correction value αH1 with a negative sign and a relatively large absolute value, and output the evaluation photometric value E as shown in (i) of FIG. 14(a). good.

(a-ii) PH, <ΔBA, Q H2<ΔCB
≦QHI (STEP 113) As shown in FIG. 13(a), ΔBA is a positive predetermined value P.
A predetermined value Q that is larger than H1 and ΔCB is negative and larger than +2 and positive. If it is smaller than 1, then Figure 14 (
This is a case of a luminance distribution as shown in (ii) of a). In such a case as well, it can be estimated that the scene is a backlit scene, as in case (1). Looking at the variations in the brightness signals, only the brightness signal A has a relatively low brightness, and it is thought that the main subject is placed only in the area where the brightness signal A is output. In addition, the size of the main subject in such a case may be approximately the same size as the area that outputs the brightness signal A, or it may be slightly smaller than this area, and in the former case, the brightness difference ΔBA is In the latter case, the brightness signal A itself is already influenced by the background brightness, and the brightness difference ΔBA tends to become relatively small. In either case, if the brightness difference ΔBA is larger than the positive predetermined value PH1 and it is detected that the main subject with relatively low brightness is placed near the focus detection point, focus detection as shown in the figure is performed. Point-weighted average photometric value E. In contrast, while fully considering the brightness of the main subject and also taking into account the brightness of the background, the correction value αH1 for case (i) and between roads etc.
It is preferable to output the evaluation photometric value E using .

(a-iii) PH1<ΔBA, ΔCB≦QH2(
STEP 114) As shown in FIG. 13(a), ΔBA is a positive predetermined value P.
This is a case where 8CB is larger than H1 and smaller than a negative predetermined value QH2, and the brightness distribution is as shown in (iii) of FIG. 14(a). Such a brightness distribution appears when a locally high-brightness object exists in the area where the brightness signal B is output. In such a case, if you correct the effect of this local high-brightness subject, it will be possible to give a suitable exposure to the entire screen.
As shown in (iii) of FIG. 14(a), using the correction value α8□ with a negative sign and a relatively small absolute value,
It is preferable to output the evaluation photometric value E.

(a-iv) P H2<ΔBA≦P Hl , Q
H+ <ΔCB (STEP 115) As shown in FIG. 13(a), ΔBA is a negative predetermined value P.
1.2 and smaller than a positive predetermined value PH1, Δ
This is a case where CB is larger than a positive predetermined value QH+, and the brightness distribution is as shown in (iv) of FIG. 1.1(a). In such a case as well, it can be estimated that the scene is a backlit scene, as in case (i). Paying attention to the variations in the brightness signals, we see that brightness signals A and B are lower in brightness than brightness signal C, and the main subject is divided into an area that outputs brightness signal A and an area that outputs brightness signal B. It is thought that they are located over a fairly wide area. In the case of such a brightness distribution, it is preferable to output a photometric value that places more emphasis on the area determined to be the main subject, but the focus detection point weighted average photometric value E. As shown in the figure, since it is somewhat influenced by the brightness of the high-brightness background area, it is preferable to output the evaluation photometric value E using the case (iii) and the correction value α8□ for road gaps, etc.

(a-v) PH2<ΔBA≦P) I+, QH□kuΔCB
≦QH+ (STEP 116) As shown in FIG. 13(a), ΔBA is a negative predetermined value P.
Greater than H2 and smaller than the positive predetermined value PH1, Δ
CB is thicker than the negative predetermined value QH□ (and the positive predetermined value Q
This is a case where the luminance difference is smaller than HI and the luminance difference is small as shown in (V) of FIG. 14(a).

Such a brightness distribution occurs in the case of a backlit scene similar to case (ii) in which the size of the main subject becomes even smaller and it becomes difficult to detect the brightness of the main subject, and in case of (iv). ), but the size of the main subject is even larger, such as a landscape scene where the main subject takes up almost the entire screen. Even in the case of a backlit scene where the main subject is small, it is better to treat it as a backlit landscape scene under these circumstances, so set the correction value to 0 to give the entire screen an appropriate exposure.
Focus detection point weighted average photometric value E. Evaluate the photometric value E as it is
It is better to output it as

(a-vi) PH2<ΔBA≦PH1, 8CB≦Q
H2 (STEpH7) As shown in FIG. 13(a), ΔBA is a negative predetermined value P.
) is larger than 12 and smaller than the positive predetermined value PH1, and 8CB is smaller than the negative predetermined value QH2.
This is a case of a luminance distribution as shown in (vi) of a). Such a brightness distribution appears when a main subject with fairly high brightness is placed in both the area where brightness signal A is output and the area where brightness signal B is output, and in many cases, With respect to the luminance signal C indicating general brightness outdoors, the main subject with considerably high luminance is a subject with high reflectance (whitish). Therefore, in such a case, it is best to output the evaluation photometric value E using the case (iii) and the correction value α8□ for road gaps, etc., as shown in the figure, so that the main subject part is depicted as whitish to some extent. good.

(a-vii) ΔBA≦PH2, QHl ΔC
B (STEPllB) As shown in FIG. 13(a), ΔBA is a negative predetermined value P.
This is a case where ΔCB is smaller than H2 and larger than a positive predetermined value QHI, and the brightness distribution is as shown in (vii) of FIG. 14(a). This kind of brightness distribution appears when the main subject itself has a considerable contrast ratio, or when a landscape scene has a special composition, but these are not very common scenes and occur very rarely. few.

In this case, it is better to give the correct exposure to the entire screen, and set the correction value to 0 as in the case of (V).
, focus detection point weighted average photometric value E. It is better to output the evaluation photometric value E as it is.

(a-viii) ΔBA≦PH2, QH2<Δ
CB≦Q)II (STEpH9) As shown in FIG. 13(a), when ΔBA is a negative predetermined value P
smaller than H2 and thicker than the predetermined value QH□ where ΔCB is negative (
, and smaller than the positive predetermined value QHI, as shown in FIG.
This is a case of a brightness distribution as shown in (viii) of a). In such a case, as in the case (vi), it can be estimated that the main subject is a highly reflective (whitish) subject. Further, in such a case, it can be determined that the size of the main subject portion is smaller than in the case (vi). In the case of such a subject, it is necessary to depict the main subject part as whitish to some extent, but as shown in the figure, the focus detection point weighted average photometric value E. If used as is, it is possible to give the desired exposure, so it is better to output the evaluation photometric value E using the correction value 0.

(a-ix) ΔBA≦P)12, ΔCB≦QH
2 (STEP 120) As shown in FIG. 13(a), ΔBA is a negative predetermined value P.
This is a case where ΔCB is smaller than a negative predetermined value Q, 42, and the brightness distribution is as shown in (ix) of FIG. 14(a). In this case, it is presumed that the subject is the same as in case (vl), and the size of the main subject can be judged to be intermediate between cases (vi) and (viii). In addition, in such a case, the area near the focus detection point is even more bright than in cases (vi) and (viii), and there may be a subject with a higher reflectance, or there may be some kind of light source. It can be determined that if the In such a case, the focus detection point weighted average photometric value E is used as shown in the figure. Even if you use , the main subject will be rendered whitish to some extent, but considering the balance with the peripheral areas of the screen, in order to render the main subject even whitish, (iii) and the correction value for the distance between It is preferable to output the evaluation photometric value E using αH2.

(b) When C<K: Indoor scene (b-i)
PLI<ΔBASQL1<ΔCB (STEP 129) As shown in FIG. 13(b), ΔBA is a positive predetermined value PL.
This is a case where ΔCB is larger than a positive predetermined value QLI, and the luminance distribution is as shown in (i) of FIG. 14(b). In such a case, the background part is not very bright and the main subject part has a much lower luminance than the background part, so the main subject is placed in a position that is not illuminated by the indoor lighting. Scenes etc. are assumed. Furthermore, a scene in which a somewhat low reflectance (darkish) object is placed near the focus detection point is also assumed. Further, the size of the main subject is considered to exist over part of the area where the brightness signal A is output and the area where the brightness signal (b) is output, similar to (a-i).

Under such conditions, in order to depict the situation of the subject observed by the photographer in accordance with the photographer's sensibilities, the main subject should be rendered slightly darker to the extent that the details are not lost. It is desirable to provide such exposure.

Therefore, as shown in (i) of FIG. 14(b), the focus detection point weighted average photometric value E. On the other hand, it is preferable to obtain the evaluation photometric value E using a correction value αLl having a negative sign and a relatively small absolute value.

(b-4i) PLl<ΔBA, Q L2 <ΔC
B≦QLI (STEP 130) As shown in FIG. 13(b), ΔBA is a positive predetermined value P.
If ΔCB is larger than the negative predetermined value QL2 and smaller than the positive predetermined value QLI, then
This is a case of a brightness distribution as shown in (43) of b).

In such a case, as in case (i), it can be estimated that the main subject is a dark scene. Furthermore, it can be determined that the size of the main subject is slightly smaller than in case (i), similar to case (a-ii). Even in cases like this (
As in the case of i), it is desirable to render the main subject part slightly blackish, so as shown in the figure, (i)
), and the evaluation photometric value E using the correction value αL1 for road gaps, etc.
It is better to output

(b-iii) PL<ΔBA, ΔCB≦QL2(S
TEP131) As shown in FIG. 13(b), ΔBA is a positive predetermined value P.
This is a case where ΔCB is larger than LI and smaller than a negative predetermined value QL2, and the luminance distribution is as shown in (iii) of FIG. 14(b). Such a brightness distribution appears when there is a locally high-brightness object such as an illumination light source in the area where the brightness signal B is output. In such a case, the focus detection point weighted average photometric value E. In order to give a suitable exposure for such a scene where the main subject part is depicted as somewhat dark due to the influence of this high brightness area, the correction value is set to 0 and the focus detection point weighted average is set as shown in the figure. Evaluation photometry 17 using the photometry value E0 as it is! E
It is better to output it as

(b iv) PL2<ΔBA≦PLl, QLI<
ΔCB (STEP 132) As shown in FIG. 13(b), ΔBA is a negative predetermined value P.
larger than L2 and smaller than a positive predetermined value PLI,
This is the case where ΔCB is larger than the positive predetermined value QLI, and the brightness distribution is as shown in (iv) of FIG. 14(b). In such a case, as in case (i), it can be estimated that the main subject is a dark scene. Further, as in (a-iv), the size of the main subject is larger than in case (i), and it can be determined that the main subject is arranged over a wide area of the photographic screen. Even in such cases,
As in the case of (i), it is desirable to depict the main subject part slightly blackish, but as shown in the figure, the focus detection point weighted average photometric value E is used. is a value that gives a fairly suitable exposure even as it is, so the correction value is set to 0 and the focus detection point weighted average photometric value E is calculated. It is better to output it as is as an evaluation photometric value.

(b-v) PL2<ΔBA≦PLI, QL2<ΔC
B≦QL2 (STEP 133) As shown in FIG. 13(C), ΔBA is a negative predetermined value P.
Greater than L2 and smaller than the positive predetermined value PLI, Δ
CB is larger than the negative predetermined value QL2 and is a positive predetermined value Q
This is a case where the luminance difference is smaller than LI and the luminance difference is small as shown in (V) of FIG. 14(b).

Such a brightness distribution appears in situations similar to (a-v), but especially in indoor scenes, bright and dark areas coexist within each area, and brightness signals A, B, and C are output as middle areas. As a result, there are many scenes where the brightness difference becomes small. In such a case, as in (a-v), the correction value is set to 0 to give proper exposure to the entire screen, and the focus detection point weighted average photometric value E is set. It is better to output the evaluation photometric value E as it is.

(b vi) PL2<ΔBA≦PLl, ΔCB≦
QL2 (STEP 134) As shown in FIG. 13(b), ΔBA is a negative predetermined value P.
Greater than L2 and smaller than the positive predetermined value PLI, Δ
In the case where CB is smaller than the negative predetermined value QL2, FIG.
This is a case of a brightness distribution as shown in (vi) of b).

Such a brightness distribution appears because the main subject exists in both the area where the brightness signal A is output and the area where the brightness signal B is output, the main subject is illuminated by the illumination light, and the other background areas are This is the case when the brightness is relatively high. In such a case, in order to give a suitable exposure that emphasizes the main subject part while also taking into account the luminance signal of the background part, the correction value α1 with a positive sign is set as shown in the figure. It is preferable to output the evaluation photometric value E using □.

(b-vii) ΔBA≦PL2, Q Ll
<ΔCB (STEP 135) As shown in FIG. 13(b), ΔBA is a negative predetermined value P.
This is a case where ΔCB is smaller than L2 and larger than a positive predetermined value QLI, and the brightness distribution is as shown in (vii) of FIG. 14(b). Similar to (a-vii), such a brightness distribution appears under special circumstances,
In this case, as in (a-vii), it is preferable to give appropriate exposure to the entire screen, so the correction value is set to 0 and the focus detection point weighted average photometric value E is set. It is better to output the evaluation photometric value E as it is.

(b-viii) ΔBA≦PL2, QL2×ΔCB
≦QLI (STEP 136) As shown in FIG. 13(b), ΔBA is a negative predetermined value P.
This is a case where ΔCB is larger than the negative predetermined value QL2 and smaller than the positive predetermined value QLI, and the luminance distribution is as shown in (viii) of FIG. 14(b). In such a case, as in case (vi),
It can be estimated that the scene is such that only the main subject part has relatively high brightness due to illumination light or the like. Further, the size of the main subject portion can be determined to be smaller than in case (vi) from the distribution state of the luminance signal. In such a case, in order to give an exposure that takes into account the luminance signal of the background to some extent while emphasizing the luminance signal of the main subject, the focus detection point weighted average photometric value E is used as shown in the figure. In contrast, it is preferable to output the evaluation photometric value E using the case (vi) and the correction value αL2 for the road gap, etc.

(b-ix) ΔBA≦PL2, ΔCB≦QL2
(STEPI37) As shown in FIG. 13(b), ΔBA is a negative predetermined value P.
This is a case where ΔCB is smaller than a negative predetermined value QL2, and the luminance distribution is as shown in (ix) of FIG. 14(b). In this case, it is presumed that the subject is the same as in case (vi), and the size of the main subject can be judged to be intermediate between cases (vi) and (viii). . Also, in this case, compared to cases (vi) and (viii),
The area near the focus detection point has even higher brightness, and the main subject illuminated by the illumination light has a slightly high reflectance (slightly whitish), or the main subject is illuminated behind or near the main subject. A scene in which a light source is placed is assumed. In such a case, in order to render the area near the focus detection point a little whitish and give an exposure that takes into account the balance of the entire screen while emphasizing the main subject, use (Vi) as shown in the figure. It is preferable to output the evaluation photometric value E using the correction value αL2 for the distance and road distance.

As explained above, in this example, the situation of the subject is
The configuration is such that the exposure correction value α is classified into eight types and the optimum exposure correction value α is selectively determined under each condition. Note that the magnitude relationship of the above-mentioned exposure correction values can be summarized as follows.

αM+<αH2<O αL, <0<αL2 Also, regarding the magnitude relationship between αH1 or αH2 and α, the predetermined value PHII pH□+QHI+QH2
+PLl + PL2+ QLl + It differs depending on the setting of QL2, but when compared when the brightness differences ΔBA and ΔCB are values such as between roads, generally αH2<α1. It is desirable to do so.

In the method for determining the exposure correction value α explained above, to simplify the explanation, the scene was classified in nine ways based on the brightness difference ΔBA and ΔCH.
Especially in situations where the selection result of the exposure compensation value α changes greatly depending on the brightness difference, such as the classification of the states in b) and (ii) and the state in (V), more detailed classification is necessary. It is desirable to do so. Furthermore, even when classifying the object scene based on the luminance signal C, it is desirable to perform more detailed classification. Classifying the scene more closely in this way makes it possible to reduce exposure unevenness when there is a slight change in the photographic composition and to obtain stable exposure.

A photometric device configured to output an appropriate photometric value by analogizing the situation of the object using the luminance signal differences ΔBA and ΔCB and the luminance signal C at the periphery of the photographic screen is disclosed by the same applicant. It is disclosed in Japanese Unexamined Patent Publication No. 184319/1983.

In addition, the focus detection point weighted average photometry in this embodiment is an operation for calculating an average value using the importance of the luminance signal of the divided small area as a coefficient according to the position of the selected focus detection point. , when the left focus detection point is selected, when the center focus detection point is selected, and when the right focus detection point is selected, the coefficients of the importance of each area are shown in FIGS. 15(a) and (b), respectively. ).

It looks like (c). It goes without saying that the combination of importance coefficients is not limited to this.

Furthermore, in the above embodiment, the flash photography conditions were classified into three stages based on the value of the brightness signal A in the area near the focus detection point.
It goes without saying that a more detailed classification would be even more effective. In addition, in the description of the above embodiment, the luminance difference DEL
Although TA is compared with a predetermined value only when the brightness is high, it can also be considered that it is compared with a predetermined value 0 even when the brightness is low, and the flash light emission conditions are determined based on the brightness A of the predetermined area. When comparing the brightness difference DELTA, set the predetermined value to 0°r.
It can also be characterized as determining the flash light emission condition by changing it into three stages: L+rH.

[Other Examples]

FIGS. 16(a) and 16(b) are diagrams showing divided shapes of a photometric light receiving section according to another embodiment of the present invention. In the first embodiment of the present invention, the photometric light receiving section is divided into 15 small areas of the same shape, but it may be divided into small areas of different shapes and areas as shown in FIG. 16. However, in such a case, when classifying the luminance signal of a small area into a medium area, care must be taken so that the area of each medium area does not change significantly due to the selection of the focus detection point.

In Figures 16(a) and (b), the field of view is 11
However, the advantage of having a small number of divisions is that it simplifies the photometry circuit and reduces the cost of the light receiving element for photometry. In addition, when the light-receiving section for photometry is divided as shown in Figure 16, the small light-receiving areas placed around the periphery of the photographic screen are further connected in series to effectively divide the light-receiving section for photometry. It is also possible to reduce the number of divisions.A technique for reducing the number of divisions of the photometric light receiving section in this way is disclosed in Japanese Patent Application Laid-Open No. 125527/1983 filed by the same applicant.

〔Effect of the invention〕

The present invention divides a field into a plurality of areas and detects the brightness of each of these areas.The difference between the brightness of a specific area within this area and the maximum brightness is determined, and the difference between the brightness of a specific area within the area is determined. By comparing the error value with a predetermined value that varies depending on the brightness value of the area, it is determined whether flash light emission is necessary or not, making it possible to easily distinguish between backlight conditions and low brightness conditions, and to make the determination accurate. We can provide cameras that can

[Brief explanation of drawings]

FIG. 1 is a diagram showing the divided shape of the photometric light receiving section of the first embodiment of the present invention, FIG. 2 is a sectional view of the optical system of the camera of the first embodiment of the present invention, and FIG. 3 is a diagram of the present invention. A perspective view of a multi-point focus detection optical system according to the first embodiment, FIG. 4 is a diagram showing the circuit configuration of a camera according to the first embodiment of the present invention, and FIGS. 5 to 11 are diagrams showing the first embodiment of the present invention. 12 to 15 are explanatory diagrams for explaining the flowchart of the first embodiment of the present invention. FIG. 16 shows the divided shape of the photometric light receiving section of another embodiment of the present invention. figure. 6...Photometry light receiving section 15...Focus detection light receiving section 22...Central processing unit CPU 5//tz, 5'/J4Sza(Vii) (STEP//IF) c iv> C5rEPtis) (1) (STEPttz) CV surface C3TEpHf ) (V) C3el16) (ii) (5TEP"3) tir) C3rEPtzo) <vin (5-7EP//7) Cjii) (5IEPI'4) (Vii) t5T'EPI3 phantom C'+v) C5TPtiz) ci+ (STEP/η) (Viii) (sVl:Ptgb)CV) (Sr
EFIE) (ii) (r pressure P/ri) ('Ix) (STEP/m) (V+) C3TEP/N) (iii) C5TEP/31> L 5C S bar L C R

Claims (2)

[Claims] (1) a light receiving means that divides a field into a plurality of regions and detects the brightness of each divided region; first brightness information of a specific region among the plurality of regions;
brightness difference detection means for detecting a difference from second brightness information indicating a maximum value among the plurality of areas; and information on the difference determined by the detection means is changed depending on the value of the first brightness information. A camera comprising: a light emission determining means for determining flash light emission by comparing it with a predetermined value. (2) The camera according to claim 1, wherein the specific area is an area including a focus detection area.