JPH1164920A - Exposure controller for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure controller for a camera capable of obtaining a proper photometric value which gives priority to a main object, even if it is not located in the center of a photographic picture. SOLUTION: Relating to the camera 10 provided with a division photometry sensor 20 capable of dividing a photometry area corresponding to the photographic picture into plural areas and independently executing the photometry of each divided photometry area, tentative composition is decided and after that, when composition is changed, the movement of the camera 10 is detected as turning angles θx and θy with angular velocity sensors 31 and 33. Then, the position on the photographic picture in the composition after being changed, of the main object located in the center of the photographic picture in the tentative composition is detected from the rotational angles θx and θy and the focal distance (f) of a photographic lens 51, to detect the corresponding divided photometry area, so that the luminance of an object is obtained by a division photometric operation expression for executing fixed weighing for each photometric value of the division photometry sensor in the composition after being changed and the photometric value of the divided photometry area decided by a detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control apparatus for an autofocus camera capable of performing divided photometry.

[0002]

2. Description of the Related Art In general, a camera equipped with a divided photometric sensor capable of performing multi-photometric measurement generally assigns the most weight to the photometric value of a divided photometric sensor (photometric zone) corresponding to the center of the screen and performs photometric calculation ( Luminance Bv calculation). However, in actual photographing, the main subject is not always located in the central photometric zone, and is often out of the central photometric zone. Therefore, an appropriate photometric value (brightness Bv) cannot be obtained for the main subject in many cases.

In order to solve such a problem, there is a so-called AE lock photographing method in which a main subject is first captured at the center of a photographing screen, photometry is performed, the photometric value at that time is stored, and then the composition is changed to photograph. there were. However, in this case, since the photometry is performed in a composition different from the composition to be actually photographed, an appropriate photometry value cannot be obtained for the entire photographic screen centering on the main subject.

FIG. 4 shows a state of a subject image by a photographing method in which the composition is changed after the focus lock is applied (hereinafter, referred to as "focus lock photographing method"). In the figure, the photographing screen is divided into nine regions, and the photometric sensor is capable of performing photometry for each of the divided regions. Symbols A to I are assigned to the divided photometric areas corresponding to the areas. The photometric sensor can independently perform photometry for each of the divided photometric areas A to I.

In the focus lock photographing, first, in a temporary composition in which a person who is a main subject is captured in a central photometry area E (FIG. 4A), focus adjustment processing is performed to focus on the main subject. In addition to the focus lock, photometric processing is performed, photometry is performed for each photometric area, subject brightness Bv is calculated, stored, and AE locked. The divisional photometry calculation equation is, for example, as shown in the following Equation 1.

(Equation 1) In this division calculation expression, the photometric area E is weighted twice as much as the other photometric areas (A, B, C, D, F, G, H, and I). The subject brightness Bv obtained by the divisional photometry calculation becomes higher as a whole because the sun is in the photometry area A.

Next, the camera is panned to the composition desired to be photographed (FIG. 4B). Composition after this change (shooting composition)
Although the person is in the photometric area C, the sun is located outside the photometric area, that is, outside the shooting screen, so that the entire shooting screen becomes dark. However, the photometry in the composition before the change measures a portion different from the subject in the composition after the change. Therefore, when photographing is performed with the subject brightness Bv locked with AE in the temporary composition, photographing with an appropriate exposure value cannot be performed. As described above, with the conventional focus lock photographing method, an appropriate photometric value and exposure value cannot be obtained.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a camera exposure control apparatus capable of obtaining an appropriate photometric value with emphasis on a main subject even if the main subject is not located at the center of a photographing screen. I do.

[0008]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention is directed to a camera provided with a divided photometry device capable of dividing a photometry area corresponding to a photographic screen into a plurality of areas and performing photometry, and then determining a desired composition after determining a temporary composition. When the composition is changed to composition, photometry is performed to detect where the main subject image at the center of the shooting screen in the temporary composition has moved on the shooting screen in the shooting composition, and to obtain a divided photometry area corresponding to the position after the movement. Then, a photometric value (subject brightness) is obtained by a divided photometric operation in which the photometric value of the divided photometric area is weighted.

The amount of movement of the main subject image on the image plane is represented by f the focal length of the photographing lens, θx the horizontal rotation angle of the camera moved to change the composition, θy the vertical rotation angle, and X and y in the horizontal and vertical directions of the main subject are calculated by the equation x = ftan xy. The rotation angles θx and θy are detected using a horizontal angular velocity sensor and a vertical angular velocity sensor provided in the camera. That is, by integrating the angular velocity detected by the angular velocity sensor with the time required to move from the temporary composition to the photographing composition, the rotation angles θx and θy can be obtained. Then, a divided photometric area corresponding to a position on the photographing screen after the central main subject image has moved by the moving amount x and y is obtained, and the divided photometric area (the photometric signal) is weighted by a divided photometric computing equation. A photometric value (subject brightness Bv) is obtained.

When the present invention is applied to a camera equipped with an automatic focus adjustment device, the focus is adjusted for the main subject when the tentative composition is determined, and the in-focus state is maintained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of a single-lens reflex camera (hereinafter, referred to as an “AF single-lens reflex camera”) provided with an automatic focusing apparatus to which the present invention is applied, and FIG. 2 shows an image plane divided into nine areas (photometry areas). It is a figure showing an example of a light sensing surface of a division photometry sensor provided with a division photometry area which can divide and measure photometry.

The AF single-lens reflex camera 10 has a photographing lens (zoom lens) 51 detachably attached to a camera body 11.
Is installed. A part of the subject light beam incident from the photographing lens 51 passes through the main mirror 12 and is reflected by the sub-mirror 13 to form a distance measuring sensor (AF sensor unit) 1.
4 is incident. The remainder of the subject light beam incident on the main mirror 12 is reflected here, forms a subject image on the finder screen (focusing screen) 15 (projects the subject image), and transmits the subject image. Finder screen 1
Reference numeral 5 is arranged at an optically equivalent position to a photographing screen (film surface) 16 on which a subject image is formed when the main mirror 12 is raised. The subject luminous flux transmitted through the finder screen 15 is reflected by the pentaprism 17,
Part of the light passes through the eyepiece 18 and exits, and part of the light passes through the photometric lens 19 and enters a photometric sensor 20 serving as a divided photometric unit.

The photometric lens 19 and the photometric sensor 20 are
The subject image substantially the same as the subject image formed on the photographing screen 16 is formed on the light receiving surface of the photometric sensor 20, that is, on the photometric area. The photometry area is formed so as to coincide with the image plane on the photographing screen 16. Further, the photometric area is divided into a plurality of divided photometric areas, and each divided photometric area is formed so that photometry can be performed independently. For example, nine divided photometric areas A to I shown in FIG. 2 are constituted by nine divided photometric sensors so that photometry can be performed independently. The number, location,
The shape is not limited to the illustrated embodiment, and may be, for example, the arrangement shown in FIG.

FIG. 3 is a block circuit diagram showing a circuit configuration of the camera 10. As shown in FIG. In the camera body 11, a CPU 21 is provided as a control means for integrally executing calculations and controls relating to autofocus and exposure. The distance measuring sensor 14 is a so-called phase difference type distance measuring sensor,
Although not shown, a split / re-imaging optical system for splitting and re-imaging a subject light beam forming a subject image included in a focus detection zone in the image plane into two parts, and receiving the two-divided subject images, respectively. Integration (photoelectric conversion and accumulation of its charge)
It has a line sensor for outputting. The output signal of the distance measuring sensor 14 is sent to the CPU via the distance measuring interface 22.
21 is read. The CPU 21 calculates a defocus amount based on the read signal, obtains a drive direction and a drive amount of the AF motor 23 necessary for moving the focus adjustment lens group L1 to a focus position, and obtains a motor driver 2
4 to drive the AF motor 23. AF motor 23
Is calculated as the number of pulses of the photo-interrupter 25 that outputs a pulse in conjunction with the rotation of the AF motor 23, and the driving amount of the AF motor 23 is
The number of pulses output from the counter 5 is counted by the counter 26, and control is performed based on the count value.

The rotation of the AF motor 23 is controlled by the camera body 1
The light is transmitted to a focus lens driving mechanism 53 of the photographing lens 51 via a joint mechanism provided on the photographing lens 51 and the photographing lens 51, and the focus adjusting lens group L1 is moved forward and backward by the focus lens driving mechanism 53.

The photographing lens 51 has a CPU 55 mounted thereon. At least lens information such as an open aperture value and a minimum aperture value including the focal length of the photographic lens 51 is written in the built-in ROM of the CPU 55, and the information is read by the CPU 21 of the camera body 11.

Each of the divided photometric sensor signals corresponding to each of the divided photometric areas output by the photometric sensor 20 is read into the CPU 21 via the photometric interface 27, and the built-in A
The signal is converted into a digital signal by a / D converter, and is temporarily stored in a storage unit (such as a built-in RAM).

The camera body 11 is equipped with a horizontal angular velocity sensor 31 and a vertical angular velocity sensor 33 for detecting the movement (horizontal direction, vertical direction) of the single-lens reflex camera 10. Outputs relating to the rotation direction and the angular velocity detected by the angular velocity sensors 31 and 33 are amplifiers 32 and 3 respectively.
4 and is amplified by the CPU 21 as an analog signal.
Is input to The CPU 21 controls each of the angular velocity sensors 31, 3
The analog signal output from 3 is converted into a digital signal by a built-in A / D converter, and is temporarily stored as X data and Y data. As the angular velocity sensors 31 and 33, for example, a ceramic gyro is used. As shown in FIG. 5, the rotation of the camera 10 in the horizontal X direction (left-right pan) and the vertical Y-direction rotation angular velocity (vertical pan) is detected. Are arranged as possible.

Further, the CPU 21 calculates the number of rotations of the camera 10 in the horizontal and vertical directions based on the X and Y data and the elapsed time. Based on the calculated rotation angle, the focal length f of the photographic lens, and the size of the photographic screen, it is calculated to which position on the photographic screen the main subject image located at the center has moved. The rotation angle can be obtained by the following equation (2), for example, when the rotation angle in the horizontal direction is θx, the rotation angle in the vertical direction is θy, and the elapsed time is t.

(Equation 2)

On the other hand, the photographing lens 51 includes a focusing lens group L1 which is moved forward and backward along the optical axis by a lens driving mechanism 53, and lens information of the photographing lens 51, for example, lens type, focal length information, open aperture, and the like. A ROM 55 in which value information, minimum aperture value information, and the like are written is provided. If the taking lens 51 is a zoom lens or a power zoom lens, the position of the zoom lens group, or a zooming mechanism and a zoom motor for driving the zoom lens group, and the position of the zoom lens group moved by the zooming are detected, for example, a brush. In addition, a lens position detecting mechanism having a code plate is incorporated.

In the drawings, reference numerals 28 and 29 indicate focusing LEDs provided in the viewfinder visual field to indicate that the subject is in focus, and information such as that the main subject has moved out of the photometry area. It is a display panel. SW1 is a distance measurement switch, and SWR is a release switch. Although not shown, the distance measurement switch SW1 is turned on by half-pressing the release button in conjunction with the release button, and further released by further pressing the release button. SWM is a main switch. When the main switch SWM is turned on, the CPU 21 supplies power to each member to be in an operable state. When the distance measurement switch SW1 is turned on, the CPU 21 executes an AF process and the like. When the SWR is turned on, the exposure processing is executed by driving the photometry processing, the divided photometry calculation processing, and the shutter and the aperture mechanism (not shown).

FIG. 4 shows how the main subject image moves by the focus lock photographing method. In FIG. 4, first, the camera 10 is set so that the main subject is located at the center of the central photometric zone E, and this position is locked as a temporary composition. Then, with the focus locked, the camera 10 is panned so that the main subject enters the photometry zone C at the upper right, and a shooting composition is taken. That is, the camera 10 is panned down diagonally to the left.

According to the embodiment of the present invention, when the composition is changed, it is detected which divided photometry area the main subject after moving has moved, and the photometry is performed with the changed composition, and the detected photometry area is detected. It is characterized in that the subject brightness Bv is obtained by a divided photometric calculation in which the photometric value is weighted.

Referring to FIGS. 5 to 8, the principle of obtaining a divided photometric area in the embodiment of the present invention will be described. FIG. 5 shows an example of the arrangement of angular velocity sensors and the relationship between directions of detectable angular velocity. . FIG. 6 shows the relationship between the angular velocity sensor and the camera body. As shown in FIG. 5, the horizontal angular velocity sensor 31 is arranged parallel to the horizontal direction of the photographing screen, and the vertical angular velocity sensor 33 is arranged parallel to the vertical direction of the photographing screen. The horizontal angular velocity sensor 31 detects the rotational angular velocity of the camera in the lateral (left / right) direction, and the vertical angular velocity sensor 33 detects the rotational angular velocity of the camera in the vertical (vertical) direction. Here, the optical axis of the camera 10 is defined as a Z axis, the vertical direction (vertical direction) is defined as a Y axis, and the horizontal direction (horizontal direction) is defined as an X axis.

FIG. 6 shows the relationship between the rotation direction of the camera 10 and the moving direction of the subject image on the photographing screen 16 in the viewfinder field. As shown in (A1) of FIG. 6, when the horizontally held camera 10 is panned to the left (+) direction, the subject image moves to the (+) right direction of the shooting screen 16 and the camera 10 is moved to the right ( When panning is performed in the (−) direction, the subject image moves to the left (−) direction of the photographing screen 16 (see FIG.
2)). Similarly, when the camera 10 held horizontally is panned in the downward (+) direction, the subject image moves in the upward (+) direction of the photographing screen 16, and when the camera 10 is panned in the upward (−) direction, the subject image is The user moves the shooting screen 16 in the downward (-) direction (FIG. 6).
(B1), (B2)). The relationship of the movement of the subject image on the photographing screen 16 due to the rotation of the camera 10 matches the relationship of the movement of the subject image on the photometry area of the photometry sensor 20.

The rotation angle of the camera 10 and the moving amount of the subject image on the photographing screen 16 are represented by f, the focal length of the photographing lens 51, and the amount by which the camera 10 is rotated to change the composition.
It can be obtained if the horizontal rotation angle θx and the vertical rotation angle θy are known. This is shown in FIG.

FIGS. 7A and 7B show the camera 10 panned θy downward and panned θx leftward. At this time, the horizontal and vertical movement amounts x and y of the main subject on the photographing screen 16 are obtained by the formula x = ftan xy x = ftan yy. Since the coordinates on the shooting screen 16 where the main subject is located are obtained from the movement amounts x and y, the corresponding divided photometry area, that is, the divided photometry area where the main subject is likely to be located can be known. Then, if the subject luminance Bv is obtained by the divided photometric operation formula in which the divided photometric areas are weighted, an appropriate value focusing on the main subject can be obtained.

An embodiment of the luminance Bv calculation formula which gives the highest weight to the divided photometry zone including the main subject is shown in the following formula (3). Note that A to I are (photometric outputs of) the divided photometric zones, and Ma is (a photometric output of) the divided photometric zones in which the main subject is included.

(Equation 3)

FIG. 8 shows an embodiment in which the position of the photometric sensor 20 in the divided photometric zone is determined from the position of the main subject image on the photographing screen 16 (image plane) of a so-called 35 mm film. . The standard shooting screen 16 for 35 mm film is 24 mm long and 36 mm wide. Of course, the present invention is a shooting screen of a new camera system,
The present invention can be applied to a panoramic shooting screen and other shooting screens, and can also be applied to a camera having an image sensor such as a CCD or a CMOS.

In FIG. 8A, the origin is at the center (on the optical axis) of the photographing screen 16, the horizontal direction is the Px axis, and the vertical direction is Py.
An axis represents a PxPy coordinate system. In the present embodiment, in order to facilitate the calculation by using the coordinate value as a positive numerical value,
The origin of the coordinates has been moved to the upper left corner of the shooting screen. This HxHy coordinate system is shown in FIG. This Hx
In the Hy coordinate system, the horizontal direction is the Hx axis, and the vertical direction is the Hy axis. To convert the coordinates on the Px Py coordinates to the Hx Hy coordinates, the following conversion formula is used. Hx = Px + 18 Hy = -Py + 12

FIG. 8C shows the relationship between the divided photometry area of the photometry sensor 20 and the photographing screen 16. In this embodiment, since the divided photometry areas A to I are composed of nine pieces in three rows and three columns, the photographing screen 16 is equally divided into nine pieces corresponding to the divided photometry areas A to I, and each divided photography area is Are assigned zone identification numbers Ar of O to 8. Furthermore, when the divided photographing areas O to 8 are specified by a 3 × 3 matrix in HxHy coordinates, they are (0, 0) to (2, 2).

FIG. 9 shows another embodiment of the photometric area dividing mode of the photometric sensor 20. In this embodiment, the vertical direction is divided into three parts, but the upper and lower parts are divided into two equal parts, and the central part is divided into three parts by widening the center to provide a total of seven divided light measuring areas.

The divided photometry processing when photographing with a different composition after locking the focus, which is a feature of the embodiment of the present invention, will be described in detail with reference to flowcharts shown in FIGS. . FIG. 10 shows a main process that is started when a battery is mounted and the main switch SWM is turned on.

In this process, first, the distance measuring switch S
It is checked whether or not W1 is turned on, and waits until it is turned on (S101: N). In this embodiment, the processing is performed on the assumption that the main subject is located at the center of the screen when the distance measuring switch SW1 is turned on. Note that the position of the main subject is not limited to the center of the screen.For example, in multi-point ranging, the movement of the main subject is determined based on the distance measurement area including the closest subject as the main subject. May be required.

When the distance measurement switch SW1 is turned on, the distance measurement sensor 14 is driven to input distance measurement data via the distance measurement interface 22 to obtain the defocus amount (S10).
1: Y, S103). Then, it is checked from the obtained defocus amount whether or not the camera is in focus. If the camera is not in focus, on the condition that the distance measuring switch SW1 is on,
An AF motor drive amount is obtained based on the defocus amount, an AF drive process is performed to drive the AF motor 23 based on the AF motor drive amount to move the focusing lens group L1 to a target position, and the process returns to S103. (S105: N, S1
07: Y, S109, S103). S103-
The processing up to S109 is repeated until focusing or the distance measurement switch SW1 is turned off. When the distance measurement switch SW1 is turned off, the process returns to S101 (S107:
N, S101).

After focusing, the focusing LED is turned on and θ
Clear the values of x and θy (S105: Y, S11
1). Then, under the condition that the distance measurement switch SW1 is on, the process waits for 1 ms (S113: Y, S117: N).
After 1 ms, the outputs of the angular velocity sensors 31 and 33 are input and A /
The D-converted data is stored as X data and Y data, and an angle calculation process for calculating the angles θx and θy panned by the camera 10 is executed (S117: Y, S119).

Then, the release switch SWR is checked. If the release switch SWR is not turned on, the process returns to S113, and the loop processing of S113 and S117 to S121 is performed on condition that the distance measurement switch SW1 is turned on. It repeats (S121: N, S113). By this loop processing in which the rotation angles obtained at predetermined time intervals (1 ms) are added, the angle panned by the camera from the time of focusing to the time when the release switch SWR is turned on is obtained. If the distance measurement switch SW1 is off, the focusing LED is turned off and the process returns to S101 (S113: N, S115, S10
1).

When the release switch SWR is turned on, the focusing LED 28 is turned off, and photometric data is input from the divided photometric sensor 20 via the photometric interface 27 (S121: Y, S123, S125). Based on the angles θx, θy and the focal length f obtained in the angle detection processing, the position of the main subject on the image plane is determined, and the divided photometric area corresponding to the position is specified (S127). Then, a photometric operation is performed with a weight on the specified divided photometric area, an exposure process is performed based on the photometric value obtained by the photometric operation, and the process returns to S101 (S129, S13).
1, S101).

Next, the angle calculation processing in step S119 will be described in more detail with reference to FIG. In this process, an analog detection signal is input from the horizontal angular velocity sensor 31 and the vertical angular velocity sensor 33 via the amplifiers 32 and 34, and the input analog signal is converted into a digital signal by a built-in A / D converter. , X data in the horizontal direction and Y data in the vertical direction are obtained. The rotation angle can be obtained by adding the detection time to the X and Y data. In this embodiment, the angle detection time is set to 1 ms, and the X and Y data are set to indicate the rotation angle. The rotation angle can be obtained by substituting 1 ms for t in Equation 2. Then, the total rotation angles θx and θy are obtained by the following expressions: θx = θx + X, θy = θy + Y, and the process returns (S203). Since this angle detection process is repeated until the release switch SWR is turned on, the rotation angle of the camera 10 from the time of focusing until the release switch SWR is turned on, that is, the rotation angle from the time of focusing is obtained.

The details of the photometric area calculation processing in step S127 will be described with reference to the flowchart shown in FIG. In this process, first, the position on the image plane is obtained from the angle data θx and θy obtained in S119 by using the following equation: Px = ftan pyx Py = ftantany (S301).

Next, in order to obtain a divided photometric area including the main subject image, coordinate conversion is performed by the following equation: Hx = Px + 18Hy = -Py + 12 (S303). In this example,
The origin is at the upper left of the shooting screen (photometry area). Then, an area determination process for obtaining a divided photometric area where the coordinates (Hx, Hy) after the coordinate conversion is performed is executed, and the process returns (S305).

Next, the details of the area determination processing in S305 will be described with reference to FIGS. In the area determination processing, where the coordinate values Hx and Hy in mm unit fall within a range obtained by dividing the horizontal and vertical directions of the photographing screen into three parts respectively, a divided photometric area where the coordinates (Hx and Hy) are located is specified. Processing. In this embodiment, since a 35 mm film is targeted, the horizontal x of the shooting screen is 36 mm and the vertical y is 24 mm.

In the area determination process, first, the variable i is cleared and it is checked whether or not the variable i is greater than 2. At first, since i is 0, the coordinate value Hx is 36 (i + 1).
/ 3, that is, whether it is 12 or less (S403: N, S405). If it is 12 or less, it is known that the horizontal coordinate value Hx is in the first column (any of the divided photographing areas 0, 3, and 6), and the process proceeds to S409, where 0 is inserted into a variable XX that designates a column ( S405: Y, S4
09).

When the coordinate value Hx is larger than 12,
1 is added to i, and the coordinate value Hx is again 36 (i + 1).
/ 3, that is, 24 or less. If it is less than 24, it is known that the horizontal coordinate value Hx is in the second row (one of the divided photographing areas 1, 4, and 7).
Proceeding to step 409, 1 is set to the variable XX specifying the column (S405: N, S407, S403: N, S405:
Y, S409).

When the coordinate value Hx is larger than 24,
i is incremented by 1, and the coordinate value Hx is again 36 (i + 1) /
It is checked whether it is 3, that is, 36 or less. If it is less than 3, it is found that the horizontal coordinate value Hx is in the third row (any of the divided photographing areas 2, 5, and 8).
09, 2 is entered into a variable XX that specifies a column (S
405: N, S407, S403: N, S405: Y,
S409).

When the coordinate value Hx is larger than 36,
The main subject is off the shooting screen in the horizontal direction, or a detection error has occurred. Therefore, 1 is further added to i, but i is 3
Is displayed, an error is displayed on the display panel 29,
Put 1 in the variable XX to identify the center column (S
405: N, S407, S403: Y, S411, S4
13).

The row of the divided photographing area where the main subject image is located is specified by the variable XX obtained by the processing of S401 to S413.

Next, S41 similar to S401 to S413
Through the processing of 5 to S427, the line of the divided photographing area where the main subject is located is specified. That is, the coordinate value Hy is 0
-8, variable YY = 0, 9-16, variable YY = 1, 17-17, variable YY = 2, 0-2
If it is not 4, an error is displayed on the display panel 29 and the variable YY = 1 is set. That is, the row of the divided shooting area where the main subject image is located is specified by the variable YY. Variable X obtained by the above processing
X and YY specify the divided shooting area where the main subject is located.

The processing of S429 to S465 is performed by dividing the divided photographing area whose coordinates are specified by the variables XX and YY.
This is processing for converting into a code Ar for identifying a divided shooting area. That is, when entering this process, the combination of XX and YY is checked, and if XX = 0 and YY = 0, Ar is set to 0 (S429: Y, S431), and XX = 1, YY =
If it is 0, 1 is set to Ar (S433: Y, S43
5), if XX = 2, YY = 0, set 2 to Ar (S437: Y, S439); if XX = 0, YY = 1, set 3 to Ar (S441: Y, S443) ,
If XX = 1 and YY = 1, 4 is set to Ar (S4
45: Y, S447), if XX = 2, YY = 1, A
r is set to 5 (S449: Y, S451), and XX =
If 0, YY = 2, set 6 to Ar (S453:
Y, S455), if XX = 1 and YY = 2, 7
(S457: Y, S459), XX = 2, Y
If Y = 2, set 8 to Ar (S461: Y, S
463), if none of the above applies, set 4 to Ar (S465) and return.

By the above-described area determination processing, the divided shooting area where the main subject gift is located after the temporary composition is changed to the shooting composition is specified as a variable Ar.

Next, the details of the divided photometry calculation process in S129 will be described in more detail with reference to the flowchart shown in FIG. This divisional photometry calculation process is performed in step S127.
This is a process of specifying a divided photometric area corresponding to the specified divided photometric area and weighting the photometric value of the specified divided photometric area to obtain the subject brightness Bv.

In this process, it is checked whether the variable Ar for identifying the specified divided photographing area is O to 8, and the identifiers A to I of the divided photometric areas corresponding to the variable Ar are determined. (S501 to S5)
35). That is, if the variable Ar is 0, A is set to the variable Ma (S501: Y, S503), and if the variable Ar is 1, B is set to the variable Ma (S505: Y, S50).
7) If the variable Ar is 2, C is set to the variable Ma (S509: Y, S511); if the variable Ar is 3, D is set to the variable Ma (S513: Y, S515); If it is 4, E is set to the variable Ma (S51).
7: Y, S519), if the variable Ar is 5, F is set to the variable Ma (S521: Y, S523), and if the variable Ar is 6, G is set to the variable Ma (S525: Y, S
527), if the variable Ar is 7, set H to the variable Ma (S529: Y, S531), and if the variable Ar is 8, set I to the variable Ma (S533: Y, S535),
If the variable Ar is not any one of 0 to 8, E is set to the variable Ma to designate the central divided photometry area for safety processing (S537), and the flow advances to S539.

When the divided photometric sensor in which the main subject is located, that is, the divided photometric sensor to be weighted is specified, the subject brightness Bv is calculated by the above equation (S539).
To return. In this equation, the values of the photometric signals output by the corresponding divided photometric sensors are substituted for the symbols Ma and AI.

As described above, according to the present embodiment, the temporary composition is determined so that the main subject is located at the center, and the distance measuring switch S
When W1 is turned on, the focus is locked. Thereafter, when the camera 10 is panned to the composition to be photographed and the release switch SWR is turned on, the position of the main subject image in the new composition is detected, photometry is performed, and the divided photometry sensor in which the main subject image is located is determined. Since the divided photometric calculation is performed by weighting the photometric values of the divided photometric sensors, it is possible to obtain an appropriate subject brightness Bv with emphasis on the main subject. In addition, the present invention may be configured to include a memory unit for the divided photometry value, and periodically and repeatedly execute the photometry and the memory of the divided photometry value and update thereof while the distance measurement switch SW1 is on. However, in this case, it waits for photometry performed after the composition change is completed.

Although the illustrated embodiment has described the AF single-lens reflex camera, the present invention can be applied to a compact camera and a manual focus camera. When applied to manual focus, it can be realized by setting the time when the distance measurement switch SW1 or another switch is turned on as a temporary composition at the time of focusing. The divisional photometry area is not limited to those shown in FIGS. 2 and 9, and the divisional photometry calculation formula is not limited to Expression 3.

[0056]

As is apparent from the above description, the invention according to the first aspect measures the photometry when the composition is changed to the desired photographing composition after the provisional composition is determined, and further, the main composition at the center of the photographing screen in the temporary composition is determined. Since it detects where the subject image has moved in the shooting composition, finds a divided photometry area corresponding to the position after the movement, and obtains the subject brightness by a divided photometry operation in which the photometry value of the divided photometry area is weighted. Photometry with emphasis on the main subject becomes possible, and shooting with an appropriate exposure value becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a single-lens reflex camera provided with an automatic focusing device to which the present invention is applied.

FIG. 2 is a diagram illustrating an embodiment of a light receiving surface of a divided photometric sensor having a divided photometric area capable of photometrically dividing an image plane into nine regions.

FIG. 3 is a block circuit diagram showing one embodiment of a circuit configuration of the single-lens reflex camera shown in FIG. 1;

FIG. 4 is a diagram illustrating a state in which a subject image moves by a shooting method in which a composition is changed after a focus lock is applied.

FIG. 5 is a front view showing the relationship between the angular velocity sensor and the camera in the same-lens reflex camera.

FIG. 6 is a diagram illustrating a relationship between an arrangement example of angular velocity sensors and directions of detectable angular velocities in the same-lens reflex camera.

FIG. 7 is a diagram illustrating a relationship between a rotation direction of the same-lens reflex camera and a moving direction of a subject image on a shooting screen.

FIG. 8 is a diagram illustrating a relationship between a divided photometry area of a photometry sensor and a shooting screen.

FIG. 9 is a diagram showing another example of division of the divided photometry area.

FIG. 10 is a flowchart illustrating a main operation of the single-lens reflex camera according to the embodiment of the present invention;

FIG. 11 is a diagram illustrating a flowchart relating to angle calculation processing of the same-lens reflex camera.

FIG. 12 is a diagram illustrating a flowchart relating to a photometric area calculation process of the same-lens reflex camera.

FIG. 13 is a flowchart showing a part of an area determination process of the same-lens reflex camera.

FIG. 14 is a flowchart illustrating a part of an area determination process of the same-lens reflex camera;

FIG. 15 is a diagram showing a flowchart relating to Bv calculation processing of the same-lens reflex camera.

[Explanation of symbols]

 Reference Signs List 10 AF single-lens reflex camera 11 Camera body 14 Distance measuring sensor 16 Photographing screen (film surface) 20 Photometric sensor 21 CPU (detecting means, calculating means) 31 Horizontal angular velocity sensor 33 Vertical angular velocity sensor 51 Photographing lens

Claims (8)

[Claims] 1. A tentative composition is determined in a camera provided with a divisional photometry device capable of dividing a photometry area corresponding to a photographing screen into a plurality of areas and independently measuring photometry in each of the divided photometry areas, and then changing the composition. A detecting means for detecting a position of the main subject positioned at the center of the photographing screen in the temporary composition on the photographing screen in the post-change composition and determining a corresponding divided photometric area; and performing photometry in the post-change composition, An exposure control device for a camera, comprising: calculation means for obtaining subject brightness by a divided photometry operation in which a photometric value of a divided photometric area determined by a detection means is weighted by a predetermined weight. 2. The detecting means comprises: a moving amount of the main subject image on a photographing screen; a focal length of a photographing lens f; a horizontal rotation angle of a camera moved to change a composition; The rotation angle x, y in the horizontal and vertical directions of the main subject on the photometry area is determined by the equation x = ftan xy, where f = tanθy, where θy is the rotation angle of θy. Camera exposure control device. 3. The camera exposure control device according to claim 2, wherein said detection means determines a corresponding divided photometric area based on the calculated movement amounts x and y. 4. The exposure control device for a camera according to claim 2, wherein the rotation angles θx and θy are detected by a horizontal angular velocity sensor and a vertical angular velocity sensor provided in the camera. 5. The camera according to claim 1, wherein the camera is provided with an automatic focusing device, and the automatic focusing device performs a focusing process on the main subject when a temporary composition is determined, and changes the composition. The exposure control device for a camera according to any one of claims 1 to 4, wherein the in-focus state is maintained irrespective of (1). 6. The camera according to claim 1, further comprising a distance measuring switch and a release switch, wherein the automatic focus adjustment device is operated when the distance measuring switch is operated, and the detecting means is configured to perform the release after the focusing. By the time the switch is turned on, the angle of rotation of the camera is detected to determine the divided photometry area, and when the release switch is turned on, the photometry device measures the light, and the exposure calculation means The exposure control device for a camera according to claim 5, wherein the calculation is performed. 7. The camera according to claim 1, wherein the camera has a release button, and when the release button is half-pressed, the distance measurement switch is turned on, and when the release button is fully pressed, the release switch is turned on. 7. The exposure control device for a camera according to 6. 8. The camera according to claim 1, further comprising: a photometering switch for operating an automatic focusing device and a photometering device; and a release switch for starting an exposure process. By detecting the angle of rotation of the camera by the time the release switch is turned on to determine the divided photometry area,
6. The exposure control device for a camera according to claim 5, wherein the calculation unit performs the split photometry calculation based on a photometry value after a release switch is turned on.