JPH10186443A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute optimum photometry where priority is given to a main subject by using a photometry sensor consisting of divided sensors whose division number is comparatively small by performing different photometric operation according to the positional states of a selected focus detection area and a photometric small area related to the focus detection area and deciding the exposure value. SOLUTION: The photometry sensor consists of eight divided sensors SO to S7. A focusing screen (corresponding to a photographic image plane) is divided into eight photometric small areas 50 to 57 corresponding to the sensors S0 to S7 so as to detect the luminance of every photometric small area. A CPU selects one range-finding area based on image deviation amount in seven range-finding areas 70 to T6. Then, an automatic focus detection circuit performs focus detecting operation in the selected range-finding area. The CPU decides the exposure value by performing the different photometric operation according to positional relation between the focused range-finding area (selected range-finding area) and the photometric small area related to the range-finding area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly to a camera having focus detecting means capable of independently detecting a focus in a plurality of regions of an object scene and dividing the object scene into a plurality of small regions for photometry.

[0002]

2. Description of the Related Art Conventionally, a photometric field is divided into a plurality of regions, and a luminance signal is output for each region, and a proper exposure is given to a photographing screen using the plurality of luminance signals. Various devices have been proposed.

[0003] For example, in Japanese Patent Application Laid-Open No. 03-223821, the present applicant divides an object field into a plurality of photometric small areas, detects the luminance of each area, and detects the luminance at a plurality of points in the same field. The plurality of photometric sub-regions are grouped concentrically around the focus detection region according to the selection of the focus detection region of the focus detection means capable of independently performing focus detection, and the average of these grouped regions is averaged. A camera that calculates the photometric value of the entire scene by changing the weight of the luminance has been proposed.

In Japanese Patent Application Laid-Open No. 5-53169,
The position of the subject in the scene to which the photographer is focused is input by detecting the gaze position of the photographer, etc., and a large number of pixels of the CCD image sensor for photometry are flexibly changed according to the subject position according to the division pattern. There has been proposed an exposure calculation device that groups a plurality of patterns and weights the average luminance of each group to obtain a photometric value.

[0005]

As described above, in order to obtain a large amount of luminance information from the object field, the photometric sensor tends to be divided into multiple parts in order to obtain an image of the object field with an optimum exposure amount. . For example, according to JP-A-5-53169, CCD
By using such an area sensor, it is possible to obtain an optimal divided photometric pattern for the subject.

However, since the area sensor is a charge accumulation type sensor, there is a problem of responsiveness at the time of low luminance.
Also, due to its high price, a photodiode type is generally widely used as a photometric sensor.

On the other hand, for this photodiode type sensor, increasing the number of divisions of the sensor section means that the light receiving area of each divided sensor becomes smaller,
As a result, the photometric capability of the photometric sensor at low luminance is reduced.

Accordingly, a divided sensor having a certain size and number is used, rather than using an area sensor composed of an aggregate of sensors having a very small size in one pixel as a photometric sensor capable of forming an arbitrary number of fine divided patterns. It can be said that the photometric sensor is generally easier to use from the viewpoint of the above-described low-luminance photometric capability and the processing capability of photometric calculation. On the other hand, a camera performs a focus detection operation in order to focus a photographic lens on a photographic subject. Sensors that perform this focus detection also tend to be multi-divided, such as 2
By using one area sensor and dividing the pixels of the area sensor to obtain a correlation, it is possible to detect the focus of many areas in the photographing screen by a known phase difference detection method.

The contents proposed so far for the relationship between the photometry area and the distance measurement area (focus detection area) are described in Japanese Patent Application Laid-Open No. 03-223821. Since the distance measurement area is considerably small, it is possible to arrange the distance measurement area almost at the center of gravity of the photometry small area including the area, and therefore, the distance measurement area corresponds to the distance measurement area where the focus detection (ranging) operation is to be performed. By performing a photometric operation such as a weighting operation on the assumption that the photometric region is the position of the main subject, an almost proper exposure could be obtained.

However, if the number of distance measurement areas is set to be substantially the same as or smaller than the number of light measurement small areas, the distance measurement areas in which the focus detection operation of the main subject is to be performed are included. It becomes difficult to arrange the photometry small area almost at the position of the center of gravity, and it becomes impossible to determine one photometry small area corresponding to the main subject position as a reference for performing photometry calculation. In other words, this means that an accurate exposure cannot be determined for the photographing subject. Such optical inconsistency, which can also be called parallax between the distance measurement area and the light measurement small area, also arises from a difference in the sensor layout shape between the distance measurement sensor and the light measurement sensor itself, or a problem in the optical configuration.

The above phenomenon will be specifically described. Fig. 4 is a view of the viewfinder.At the same time, the viewfinder screen shows seven photometry areas 70 to 76 and seven photometry sub-areas 50 to 57 of the photometry sensor composed of eight divided sensors S0 to S7. Is shown. In this case, the distance measurement areas 70, 73, and 74 respectively correspond to the light measurement small area 50 to
There is no problem because it is set at 52 center of gravity. However, as shown in FIG.
When set on the boundary between the two photometric sub-regions 50 and 51 and on the boundary between 50 and 52, and even when not on the boundary as in the distance measurement regions 75 and 76, A problem arises when the setting is significantly biased toward the peripheral side.

According to the present invention, even if the main subject exists in any of the plurality of distance measurement areas, the distance measurement area for performing the focusing operation of the main object is arranged at the center of gravity of the small photometry area including the area. Even if not, the object of the present invention is to provide a camera that uses a photometric sensor composed of divided sensors having a relatively small number of divisions and that performs optimal photometry while emphasizing the main subject and appropriately considering the entire shooting screen.

[0013]

According to the present invention, there is provided a camera comprising: (1-1) a luminance detecting means for dividing a photographing screen into a plurality of photometric sub-regions and detecting a luminance for each photometric sub-region; In a camera having focus detection means for detecting the in-focus state of each of a plurality of focus detection areas set in the screen, there are a plurality of states in which the focus detection area is located relative to a photometric small area related thereto. One of the plurality of focus detection areas is selected by the selection means, and a different photometry operation is performed depending on the position state of the selected focus detection area and the photometry small area related thereto to determine an exposure value. (1-2) Luminance detecting means for dividing the inside of the photographing screen into a plurality of photometric sub-regions and detecting the luminance of each photometric sub-region, and the in-focus state of each of the plurality of focus detecting regions set in the photographing screen In a camera having a focus detection unit for detecting the one, the detection region selection unit selects one of the plurality of focus detection regions, and when the selected focus detection region exists on a boundary between adjacent photometric small regions, A weighted photometric operation is performed for each of the adjacent photometric sub-regions to obtain respective photometric operation values, and an exposure value is determined using the photometric operation values of each of the adjacent photometric sub-regions. (1-3) a luminance detecting unit that divides the inside of a photographing screen into a plurality of photometric sub-regions and detects luminance for each photometric sub-region, and a focus state of each of the plurality of focus detecting regions set in the photographing screen In the camera having the focus detection means for detecting the focus detection area, one of the plurality of focus detection areas is selected by the detection area selection means, and the selected focus detection area is located at a certain distance from the center of gravity of the photometric small area including the focus detection area. In the case of being located eccentrically in the direction, a weighted photometric calculation is performed on each of the photometric small area including the focus detection area and at least one photometric small area in the eccentric direction of the focus detection area, and the respective photometric calculation values are calculated. Then, the exposure value is determined by using the photometric operation values of these photometric small areas. It is characterized by

In particular, (1-3-1) determining the exposure value by further weighting the photometric calculation value in accordance with the position of the focus detection area in the small photometry area including the focus detection area, etc. It is characterized by.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of an embodiment of a camera according to the present invention. In the present embodiment, the photometric device of the present invention is applied to a single-lens reflex camera.

In FIG. 1, reference numeral 1 denotes a photographing lens for convenience.
Although shown as a single lens, it is actually composed of more lenses. Reference numeral 2 denotes a main mirror, which is inclined to the photographing optical path or retreated depending on the viewfinder observation state and the photographing state. Reference numeral 3 denotes a sub-mirror, which reflects a light beam transmitted through the main mirror 2 downward of the camera body. 4 is shutter, 5
Reference numeral denotes a photosensitive member, which is composed of a silver halide film, a solid-state imaging device such as a CCD or MOS type, or an imaging tube such as a vidicon.

Reference numeral 6 denotes a focus detection unit (focus detection means), which includes a field lens 6a, reflection mirrors 6b and 6c, a secondary imaging lens 6d, an aperture 6e, and a plurality of CCs arranged near the image plane.
And a line sensor 6f made of D.

The focus detection unit 6 in the present embodiment uses a well-known phase difference method. As shown in the viewfinder view of FIG. 4, seven focus detection areas (focus detection areas) 70 to It is configured so that each of the 76 focused states can be detected.

Reference numeral 7 denotes a focusing plate arranged on a predetermined image forming plane of the photographing lens 1, and 8 denotes a pentaprism for changing a finder optical path. 9 is an image forming lens, 10 is a photometric sensor (luminance detecting means) for measuring the luminance of the subject image obtained on the focus plate 7.
The imaging lens 9 conjugately connects the focusing plate 7 and the photometry sensor 10 via the reflection optical path in the pentaprism 8.

FIG. 3 is a front view of the photometric sensor 10. or,
FIG. 4 is an explanatory diagram of the viewfinder field. Photometric sensor 10
Consists of eight divided sensors S0 to S7 as shown in FIG. 3, and focus plate 7 (which corresponds to the shooting screen) is divided into divided sensors S0 to S7 as shown in FIG. The luminance is divided into eight corresponding photometric sub-regions 50 to 57 and the luminance of each photometric sub-region is detected. (Note that the line indicating the photometry small area in FIG. 4 is a line drawn for convenience of explanation, and is not an actual finder.)
.

Note that, as shown in FIG.
3 and 74 are optically set so as to be located substantially at the centers of gravity of the photometric small areas 50, 51 and 52, respectively. Also, ranging area 71,
72 is set on the boundary between the adjacent photometric sub-regions 50 and 51 and 50 and 52, and the distance-measuring region 75 is located below the center of gravity of the photometric sub-region 53, closer to the photometric sub-region 50, and the distance is measured. Region 76
Are set eccentrically above the center of gravity of the photometric small area 54 and toward the photometric small area 50, respectively.

Reference numeral 11 denotes an eyepiece provided behind the exit surface of the pentaprism 8, and is used for observing the focus plate 7 with the eyes of the photographer.

A finder optical system is constituted by the main mirror 2, the focusing plate 7, the pentaprism 8, the eyepiece 11, and the like.

Reference numeral 21 denotes a high-brightness LED which can be visually recognized even in a bright subject, and reference numeral 22 denotes an LCD (hereinafter, referred to as SI-LCD) in which a position of a distance measuring area (ranging point) is patterned, and a distance measuring area is selected. Only the LCD pattern corresponding to the position is in a transmissive state, and the light emitted from the LED 21 behind the LCD passes through the transmissive pattern of the SI-LCD and forms an image on the focus plate 7 through the light projecting lens 23 and the light guide prism 24. And eyepiece 11
Through this, the photographer can visually recognize the selected ranging area. That is, as can be seen from the viewfinder view shown in FIG. 4, an area corresponding to any one of the distance measurement areas 70 to 76 is illuminated in the viewfinder view to display the selected focus detection area.

In FIG. 4, reference numeral 28 denotes a shutter speed display, 29 denotes an aperture value display segment, and 30 denotes a focusing mark indicating the focusing state of the photographing lens 1. Reference numeral 25 in FIG. 1 denotes an LCD in the viewfinder (hereinafter, referred to as F-LCD) for displaying photographing information outside the field of view of the viewfinder.

The light transmitted through the F-LCD 25 is a triangular prism.
By 27, the photographer is guided out of the finder field of view as shown by 25 in FIG. 4, and the photographer can know various photographing information.

Returning to FIG. 1, reference numeral 31 denotes an aperture provided in the taking lens 1, reference numeral 32 denotes an aperture driving device including an aperture driving circuit 111 described later, reference numeral 33 denotes a lens driving motor, and reference numeral 34 denotes a lens driving unit including a driving gear and the like. It is a member. Reference numeral 35 denotes a photocoupler which detects the rotation of the pulse plate 36 interlocked with the lens driving member 34 and transmits the rotation to the lens focus adjustment circuit 110.
The lens drive motor is driven by a predetermined amount based on this information and information on the amount of lens drive from the camera side, and the photographing lens 1 is moved to the in-focus position. Reference numeral 37 denotes a mount contact which serves as an interface between a known camera and a lens.

FIG. 2 is a block diagram of an electric circuit incorporated in the present embodiment, and the same components as those in FIG. 1 are denoted by the same reference numerals.

A central processing unit (hereinafter abbreviated as CPU) 100 of a microcomputer built in the camera body includes a line-of-sight detection circuit 101, a photometry circuit 102, an automatic focus detection circuit 103, a signal input circuit 104, an LCD drive circuit 105, and an LED. Drive circuit 106
, An IRED drive circuit 107, a shutter control circuit 108, and a motor control circuit 109. Further, signals are transmitted to the focus adjustment circuit 110 and the aperture control circuit 111 arranged in the taking lens via the mount contact 37 shown in FIG.

The EEPROM 100a attached to the CPU 100 has a storage function for storing various adjustment data.

The photometric circuit 102 amplifies the luminance signals of the eight photometric small areas sent from the photometric sensor 10,
Logarithmic compression, A / D conversion, and CPU1
Send to 00.

The line sensor 6f is connected to the 7 in the finder screen.
7 sets of line sensor CCD- corresponding to each ranging area 70-76
0, a known CCD line sensor composed of CCD-1 to CCD-6. The automatic focus detection circuit 103 A / D converts the voltage obtained from the line sensor 6f and sends the voltage to the CPU 100.

SW-1 (12) is the first stroke of the release button
SW-2 (13) is a release switch that turns on with the second stroke of the release button, and SW-DIAL1 and SW-DIAL2 (15) are not shown. A dial switch provided in the electronic dial is input to an up / down counter of the signal input circuit 104 and counts the amount of rotation click of the electronic dial.

The signals of these switches are applied to the signal input circuit 104
And transmitted to the CPU 100 via the data bus.

Reference numeral 14 denotes a distance measurement area selection switch (SW-AF). When the switch is turned on, a distance measurement area can be manually input.
If it is turned off, the ranging area is automatically selected. The ranging area selection switch 14 and the like constitute one element of the detection area selection means.

Reference numeral 105 denotes a well-known LCD drive circuit for driving the liquid crystal display element LCD to display an aperture value, a shutter time, a set shooting mode, and the like according to a signal from the CPU 100. This is displayed on the F-LCD 25 in the viewfinder, and at the same time, the SI-LCD 22 for superimpose is controlled to display the distance measurement detection point mark. LED drive circuit 106
Is LED for lighting (F-LED) 26 and LED 21 for superimpose
(SI-LED) is turned on and off.

The shutter control circuit 108 controls the magnet MG-1 for running the front curtain and the magnet MG-2 for running the rear curtain when energized, and opens the shutter to expose the photosensitive member to a predetermined amount of light. The motor control circuit 109 controls a motor M1 for winding and rewinding the film and a motor M2 for charging the main mirror 2 and the shutter 4. The shutter control circuit 108 and the motor control circuit 109 operate a series of camera release sequences.

FIG. 5 is a flowchart of the operation of this embodiment. Thus, the operation of the entire camera according to the present embodiment will be described. Step # 100: When the camera is set to a predetermined shooting mode from a non-operation state (this embodiment will be described based on a case where the shutter priority AE is set), the power of the camera is turned on. Step # 101: The camera waits until the release button is pressed and the switch SW1 (12) is turned on, and if the release button is pressed and the switch SW1 is turned on, the camera proceeds to step # 102. Step # 102: When the signal input circuit 104 detects that the switch SW1 has been turned on, the CPU 100 performs mutual communication with the lens mounted on the camera, and the CPU 100 performs necessary operations for photometry and AF. Lens information, e.g. opening the taking lens
Information such as FNO. And best focus position is transferred to the camera memory. Here, seven sets of line sensors CCD-0 and CCD-
1, to CCD-6 start the accumulation operation of the field light and measure the image shift amount (defocus amount) at the present time. Step # 103: In order to perform the next distance measurement, check whether the distance measurement area selection switch 14 is in the automatic mode or the manual mode, that is, manually select whether the distance measurement area is automatically selected. Check if the selection is automatic, proceed to step # 104 for automatic selection, or to step # 10 for manual selection.
Proceed to 5. Step # 104: One ranging area is selected by a ranging area automatic selection subroutine based on the image shift amounts in the seven ranging areas. Several methods can be considered as an algorithm of the automatic selection of the ranging area, but a near-point priority algorithm in which weighting is applied to the central ranging area, which is known for a multi-point AF camera, is effective. Step # 105: By turning on the ranging area selection switch 14, the ranging area selection enters the manual mode, and the photographer can operate the switch dial 15 to arbitrarily select one of the 7 ranging areas. You can choose. Step # 106: As described above, the camera automatically selects the focus detection area or allows the photographer to manually input the focus detection area.
Two ranging areas are determined. Step # 107: In the determined ranging area, the automatic focus detection circuit 103 performs a focus detection calculation to determine whether or not the ranging area can be measured. To flash the focus mark 30 on the LCD 25 in the viewfinder to warn the photographer that the distance measurement is NG. If distance measurement is possible, the process proceeds to step # 108. Step # 108: If the focus adjustment state of the focusing area selected by the predetermined algorithm is not in focus, the CPU 100 sends a signal to the lens focus adjustment circuit 110 to drive the photographing lens 1 by a predetermined amount to perform the focusing operation. Do. Step # 109: After the focusing operation, it is determined whether or not the photographing lens 1 is in focus. Shooting lens at the specified AF point
If 1 is in focus, the CPU 100 sends a signal to the LCD drive circuit 105 to turn on the focus mark 30 on the LCD 25 in the finder, and also sends a signal to the LED drive circuit 106 to measure the focus. For superimpose corresponding to the distance area
The LED 21 is turned on, and the focusing area is displayed by illuminating the distance measurement area. Then, the process proceeds to step # 110. Step # 110: At the same time, the CPU 100 transmits a signal to the photometric circuit 102 to perform photometry. At this time, the exposure value is determined by performing different photometric calculations depending on the positional relationship between the focused ranging area (the selected ranging area) and the related photometric small area.
This photometric calculation is the most important operation of the present invention, and the details will be described later.

In the case of this embodiment, "5, 6", which is the aperture value 29, is displayed using the segment and the decimal point as the photometric calculation result. Step # 111: Next, it is determined whether the photographer has accepted the focus state and the photometric value at the distance measuring point position by turning ON / OFF of SW1.
Is determined. Step # 112: Release button is depressed and switch SW2 is set to O
Judgment as to whether the switch is set to N
If the switch is in the FF state, the state of the switch SW1 is checked again. If the switch SW2 is turned on, the process proceeds to step # 113. Step # 113: The CPU 100 transmits signals to the shutter control circuit 108, the motor control circuit 109, and the aperture drive circuit 111, respectively. First, energize M2 to raise main mirror 2 and stop
After narrowing down 31, MG1 is energized and the front curtain of shutter 4 is opened. The aperture value of the aperture 31 and the shutter speed of the shutter 4 are determined from the exposure value detected by the photometric circuit 102 and the sensitivity of the film 5. After a predetermined shutter time (1/125 second) has elapsed, power is supplied to MG2 and the rear curtain of shutter 4 is closed. When the exposure of the film 5 is completed, power is supplied to M2 again, mirror down and shutter charge are performed, and power is supplied to M1 to feed the film, thereby completing a series of shutter release sequence operations.

Thereafter, returning to step # 101, the switch SW
Wait until 1 turns ON.

FIG. 6 is a flowchart of the photometric calculation (step # 110). Thus, the photometric calculation in the present embodiment will be described in detail. Step # 200: When the CPU 100 executes the photometric calculation, first, the CPU 100 sends the photometric circuit from the photometric circuit of the photometric sensor 10.
The outputs (raw object luminance signals) of the eight divided sensors S0 to S7 are fetched, and AD conversion of each output is performed. Step # 201: Next, using the lens information of the photographing lens 1 obtained by the lens communication in step # 102, such as the open FNO. Is performed to convert to a correct luminance signal of the photographing subject. (Hereinafter, these luminance signals after the output correction from the divided sensor S0~S7 sensor and e ₀ ~e _7.) Stiff ° # 202: this time, the distance measuring area automatic selection or manual input at the step # 106 As a result, one of the ranging areas 70 to 76 where the main subject exists is determined. Therefore, three types of photometric calculations I, II, I
Since one of the photometric operations in II is performed, the distance measurement area is determined first, and the process is divided into three steps. Step # 20
3: If any of the distance measurement areas 70, 73, or 74, that is, the distance measurement area at the center of gravity of the
U100 performs photometric calculation I using the subject luminance signal e ₀ to e _7. Step # 204: If any one of the distance measurement areas 71 and 72, that is, a distance measurement area on the boundary between two adjacent light measurement small areas is selected, the CPU 100 executes the photometry calculation II. Step # 205: If any one of the distance measurement areas 75 and 76, that is, a distance measurement area that is eccentric from the center of gravity of the small photometry area is selected, the CPU 100 executes the photometry calculation III. Step # 206: An optimal exposure value can be determined by performing different photometric calculations in accordance with the distance measurement area selected as described above.

Hereinafter, the three types of photometric calculation will be described. First, the photometric calculation I will be described by taking a case where the distance measurement area 73 is selected as an example.

The area ratio of each divided sensor of the photometric sensor shown in FIG. 3 is as follows.

(S0, S1, S2) :( S3, S4) :( S5, S6): S7 = 3: 2: 6: 16 Therefore, if the subject is to be fully averaged, the divided sensors S0 to S7 The calculation may be performed by the following equation using the luminance signals e _{0 to} e ₇ .

Eav = {3 (e ₀ + e ₁ + e ₂ ) +2 (e ₃ + e ₄ ) +6 (e ₅ + e ₆ ) + 16e ₇ } / 41 (unit: BV) However, the present invention Then, focus area weighted photometry for performing weighted photometry calculation according to the selected ranging area is performed.

The photometric operation I when any one of the distance measurement areas 70, 73, 74 is selected will be described assuming that the distance measurement area 73 has been selected. First, A ₇₃ = e ₁ is defined from the luminance signal e ₁ from the division sensor S1 corresponding to the photometry small area 51 including the distance measurement area 73.

Next, as for the luminance signals of the sensor units other than the divided sensor S1, the average value _B73 obtained in consideration of the area ratio as described above is defined as follows.

B ₇₃ = {3 (e ₀ + e ₂ ) +2 (e ₃ + e ₄ ) +6 (e ₅ + e ₆ ) + 16e ₇ } / 38 Further, the main subject exists in the distance measurement area 73. Based on this assumption, the obtained values of A ₇₃ and B ₇₃ are subjected to a weighted photometric calculation of the following equation with a weight on A ₇₃ , and an exposure value is calculated as a photometric calculated value.
_Ask for E73.

E ₇₃ = (2A ₇₃ + B ₇₃ ) / 3 + α where α is an exposure compensation value for backlight compensation, and BA is obtained from the above A and B values as shown in FIG. The correction amount α is determined according to this value (backlight intensity).

Also, when the distance measurement area 70 is selected, a weighted photometric operation (photometric operation I) by the following equation is executed in the same manner as above, and the exposure value E ₇₀ is determined.

A ₇₀ = e ₀ B ₇₀ = {3 (e ₁ + e ₂ ) +2 (e ₃ + e ₄ ) +6 (e ₅ + e ₆ ) + 16e ₇ } / 38 E ₇₀ = (2A ₇₀ + B ₇₀ ) / 3 + α... Next, regarding one of the distance measurement areas 71 and 72, that is, the light measurement calculation II when the distance measurement area on the boundary between the two light measurement small areas is selected, the distance measurement area The case where 71 is selected will be described as an example. Since the distance measurement area 71 exists on the viewfinder optical system and on the boundary between the light measurement small areas 50 and 51, the light measurement small area
If one of the photometric calculations (weighting area 70 or 73 is selected) weighted to 50 or 51 is selected and used as the exposure calculation value, the photometric error for the main subject may increase. (Especially when the main subject is small). Therefore, in this case, the photometric small areas 50 and 51
The photometric calculation (weighted photometric calculation) with weighting is performed separately for each, and the respective photometric calculation values E ₇₀ and E ₇₃
Then, an average value of these two photometric operation values is obtained, and this is used as the exposure value E ₇₁ when the distance measurement area 71 is selected.

That is, using the above equation, the exposure value E ₇₁ is obtained by E ₇₁ = (E ₇₀ + E ₇₃ ) / 2 = {2 (A ₇₀ + A ₇₃ ) + (B ₇₀ + B ₇₃ )} / 6. decide.

Next, in one of the distance measurement areas 75 and 76, that is, in the photometry calculation III when a distance measurement area located at a position eccentric from the center of gravity of the small photometry area is selected, the distance measurement area III is used.
The description will be made by taking the case where 75 is selected as an example.

The distance measurement area 75 is apparently
It exists at a position shifted by a half distance from the position of the center of gravity of the photometric small area 53 to the boundary in the direction of the photometric small area 50.

In this case, the photometric calculation is performed in the photometric small areas 53 and 50.
Since the weighted photometric calculation is performed separately for each of them, the respective photometric calculated values are obtained, and the two photometric calculated values obtained here are weighted and used as the exposure values when the ranging area 75 is selected. is there.

More specifically, first, a photometric operation value E _S3 obtained by performing weighted photometric operation on the photometric small area 53 is obtained from the following equation in the same manner as the photometric operation I.

A _S3 = e ₃ B _S3 = {3 (e ₀ + e ₁ + e ₂ ) + 2e ₄ +6 (e ₅ + e ₆ ) + 16e ₇ } / 39 E _S3 = (2A _S3 + B _S3 ) / 3 + α ... also, the photometric small region 50 by performing weighted photometric calculation by the formula determining the photometric calculation value E _70.

Next, the above two photometric operation values E _S3 and E _{S3
Using 70} , weighting calculation is performed on the position of the distance measurement area 75. That is, assuming that (photometric operation value of 50 light-weighted small area): (photometric operation value of 53 light-weighted small area) = 1: 2, distance measurement area
The exposure value E ₇₅ when is selected is determined by the following equation.

E ₇₅ = (E ₇₀ + 2E _S3 ) / 3 In the present embodiment, a photometric sensor that divides the photographic screen into eight small photometric areas and detects the luminance of each small photometric area, Has a focus detection unit that detects the in-focus state of each of the seven ranging areas set within, and the state in which the ranging area is located relative to the photometry sub-area related thereto is located at the center of gravity of the photometry sub-area, In addition, there are three cases: on the boundary between the two photometry sub-regions, and eccentric in a certain direction from the center of gravity of the photometry sub-regions. One is selected, and the photometric operation I, is determined by the positional relationship between the selected ranging area and the related photometric sub-area.
Distance measurement that focuses on the main subject even if the main subject is present in any of the multiple distance measurement areas by determining the exposure value by performing one of the photometric calculations II and III Even if the area is not located at the center of gravity of the photometric small area including the area, the number of divisions is 8 and the number of divisions is relatively small. It is a camera that can perform optimal photometry in consideration of the above.

In the above-described embodiment, the predetermined photometric operation I, II or III is predetermined for the seven distance measurement areas. However, after one of the distance measurement areas is selected, the distance measurement is performed. The weight of the weighted photometric calculation may be determined by a certain algorithm according to the area.

[0061]

As described above, according to the present invention, there are provided a luminance detecting means for dividing the photographing screen into a plurality of photometric small areas and detecting the luminance of each of the photometric small areas, and a plurality of focus detecting areas set in the photographing screen, respectively. In a camera having focus detection means for detecting the in-focus state, there are a plurality of states in which the focus detection area is located with respect to the photometric small area related thereto, and the detection area selection means selects one of the plurality of focus detection areas. The main subject is present in any of the plurality of distance measurement areas by selecting one of the focus detection areas and performing a different photometry operation depending on the position state of the selected focus detection area and the related photometry small area to determine the exposure value. Even if the distance measurement area for performing the focusing operation of the main subject is not disposed at the position of the center of gravity of the light measurement small area including the area, the number of divisions is relatively small. , Chief coat To achieve the camera for optimal photometric entire further imaging screen focus was appropriately considered the body.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of an embodiment of a camera according to the present invention.

FIG. 2 is a block diagram of an electric circuit included in the embodiment.

FIG. 3 is a front view of the photometric sensor according to the embodiment;

FIG. 4 is an explanatory diagram of a finder visual field according to the embodiment;

FIG. 5 is a flowchart of an operation according to the embodiment;

FIG. 6 is a flowchart of photometry calculation according to the embodiment.

FIG. 7 is an explanatory diagram of an exposure correction value.

[Explanation of symbols]

 1: Photographic lens 2: Main mirror 3: Submirror 4: Shutter 5: Photosensitive member 6: Focus detection unit 6f: Image sensor 7: Focusing plate 8: Pentaprism 9: Imaging lens 10: Photometric sensor 11: Eyepiece lens 50 ~ 57: Photometry small area 70 to 76: Distance measurement area 100: CPU 102: Photometry circuit 103: Focus detection circuit S0 to S6: Split sensors constituting the photometry sensor

Claims (4)

[Claims] 1. A luminance detecting means for dividing the inside of a photographing screen into a plurality of photometric sub-regions and detecting the luminance of each photometric sub-region, and a focus state of each of the plurality of focus detecting regions set in the photographing screen. In a camera having focus detection means for detecting the position, there are a plurality of states in which the focus detection area is located with respect to the photometric small area related thereto, and one of the plurality of focus detection areas is selected by the detection area selection means. A camera which performs different photometric calculations depending on the position state of the selected focus detection area and the related photometric small area to determine an exposure value. 2. A luminance detecting means for dividing the photographing screen into a plurality of photometric sub-regions and detecting the luminance of each photometric sub-region, and a focusing state of each of the plurality of focus detecting regions set in the photographing screen. In a camera having a focus detection means for detecting the focus detection area, one of the plurality of focus detection areas is selected by a detection area selection means, and when the selected focus detection area exists on a boundary between adjacent photometric small areas, A camera characterized in that a weighted photometric operation is performed for each of adjacent photometric sub-regions to obtain respective photometric operation values, and an exposure value is determined using the photometric operation values of each of the adjacent photometric sub-regions. 3. A luminance detecting means for dividing the photographing screen into a plurality of photometric sub-regions and detecting the luminance of each photometric sub-region, and a focus state of each of the plurality of focus detecting regions set in the photographing screen. Wherein one of the plurality of focus detection areas is selected by the detection area selection means, and the selected focus detection area is located at a distance from the center of gravity of the photometric small area including the focus detection area. In the case of being located eccentrically in the direction, a weighted photometric calculation is performed on each of the photometric small area including the focus detection area and at least one photometric small area in the eccentric direction of the focus detection area, and the respective photometric calculation values are calculated. A camera which determines the exposure value by using the photometric operation values of these photometric small areas. 4. The exposure value is determined by further weighting the photometric operation value in accordance with the position of the focus detection area in the small photometry area including the focus detection area. camera.