JP2003295048A - Camera to which digital back is attachable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of performing an optimum range-finding operation when a back cover is exchanged for a digital back. <P>SOLUTION: The camera is provided with a multipoint range-finding part 54 for outputting range-finding information being the result of the detection of a distance to a subject for every several range-finding areas; a focus control part 40 for controlling the focus position of a lens 44 based on the range-finding information outputted by the range-finding part 54; and a reception part 46 for receiving size information concerning the size of the light receiving surface of the imaging device of an electronic image pickup device from the digital back. The control part 40 changes algorithm for controlling the adjustment of the focus position of the lens based on the size information received by the reception part 46. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera to which a digital back can be attached, and more specifically, it can be used as a digital camera by replacing the back cover with a digital back when used as a silver salt film camera. The present invention relates to a camera to which a digital back can be attached.

[0002]

2. Description of the Related Art Conventionally, a back cover of a silver halide film camera is a back cover equipped with an electronic image pickup device (hereinafter referred to as "digital back").
Say ), A camera that can be used as a digital camera can detect the focus position with the built-in distance measuring module in the camera body and autofocus, and the built-in photometric device can automatically determine the exposure. Something that can be done is suggested.

Further, in Japanese Patent Laid-Open No. 2000-59655, an image sensor having a different size can be exchanged according to the purpose of photographing, and in this case, a digital display which changes the display of the photographing range according to the size of the image sensor is used. A camera is proposed.

[0004]

When the above-mentioned camera whose back cover can be replaced with a digital back is used as a digital camera, the photographing range may be narrowed depending on the size of the light receiving surface of the image pickup device. In this case, if one focus detection area is selected from a plurality of focus detection areas and autofocus is performed, the focus detection area is located outside the shooting range, or even if the shooting range is within the shooting range, There is a problem that the focus area is automatically focused on a range-finding area near the boundary, which is different from the photographer's intention.

Further, even when the exposure is automatically determined by using the divided photometric elements, if the weighting is applied to the information of the subject outside the photographing range, the exposure may be incorrect.

Therefore, one of the technical problems to be solved by the present invention is to provide a camera capable of performing an optimum distance measuring operation when the back cover is replaced with a digital back. is there. Another technical problem to be solved by the present invention is to provide a camera capable of performing optimal photometric operation when the back cover is replaced with a digital back.

[0007]

In order to solve the above technical problems, the present invention provides a camera having the following configuration.

The camera is of a type that can be used as a digital camera by replacing the back cover when used as a silver salt film camera with a digital back having an electronic image pickup device. The camera includes a multi-point distance measuring unit, a focus control unit, and a receiving unit. The multi-point distance measuring section outputs distance measuring information which is a result of detecting a distance to a subject for each of a plurality of distance measuring areas. The focus control unit,
The focal position of the lens is controlled based on the distance measurement information output by the multipoint distance measuring unit. The receiving unit receives size information regarding the size of the light receiving surface of the image pickup element of the electronic image pickup device from the digital back. The focus control unit, based on the size information received by the receiving unit,
The algorithm for controlling the focal position of the lens is changed.

According to the above arrangement, the algorithm for controlling the focal position of the lens when the digital back is mounted (hereinafter, also referred to as "focusing algorithm") depends on the size of the light receiving surface of the image pickup device. It can be changed to an appropriate algorithm. This makes it possible to perform an optimum distance measuring operation when the back cover is replaced with a digital back.

Preferably, the camera outputs the photometric information which is the result of detecting the brightness of the object for each of the plurality of photometric areas, and based on the photometric information output by the multipoint photometric unit. And an exposure control unit that controls the exposure. The exposure control unit changes an algorithm for controlling the exposure based on the size information received by the receiving unit.

According to the above configuration, the algorithm for controlling the exposure when the digital back is mounted is as follows:
It is possible to change to an appropriate algorithm according to the size of the image sensor. As a result, it is possible to perform an optimum photometric operation when the back cover is replaced with a digital back.

Preferably, the camera includes a display section and a display control section. The display unit displays the selection of the distance measurement area. The display control unit changes the display displayed by the display unit based on the size information received by the receiving unit.

With the above arrangement, when the digital back is attached, the display for selecting the distance measuring area can be changed in accordance with the focusing algorithm changed according to the size of the light receiving surface of the image pickup device. it can. As a result, it is possible to easily confirm the distance measuring area (or the focusing algorithm) selected when the back cover is replaced with the digital back.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

FIG. 15 is a general view of the camera as seen from the back. A back cover 20 for use as a silver film camera is attached to the camera body 10.

On the upper part of the camera body 10, an accessory shoe 11 for mounting an external flash, IS
An O setting dial 12, a finder window 18, a mode setting dial 13, a main switch 14, and a setting change dial 15 are arranged. A rewind button 16 for rewinding the film and an eye start ON / OFF switch 17 are arranged at the bottom of the camera body 10.

The back cover 20 is rotatably supported by the camera body 10 and is detachable from the camera body 10.
A film confirmation window 22, a display unit 24, a setting button 26, and an AF area selection switch 28 are arranged on the back cover 20.

FIG. 16 is an overall view of the camera body 10 when a digital back 30 for use as a digital camera is mounted instead of the back cover 20.

The digital back 30 has a memory card loading section 32 for loading a memory card for recording data such as images and sounds, a liquid crystal monitor 34 for displaying captured images, a setting button 36, a main switch and a mode dial. 37 and an AF area selection switch 38 are arranged. The main switch and mode dial 37 is a rotary dial having four positions, and the power of the digital back 30 is turned off, a setup mode for performing various settings as a digital camera, a shooting mode for use as a digital camera, and image reproduction. You can select one of the playback modes. The power of the digital back 30 is turned on at a position other than the power off.

FIG. 1 is a circuit block diagram of the camera body 10.

The camera CPU 40 includes a display unit 41, a photometry unit 42, a light control unit 43, a lens 44, and an external flash 4.
5, adjustment terminal 46, E ² PROM 47, DC / DC converter 48, battery check circuit 59, switches 50, diaphragm drive unit 51, shutter mechanical charge unit 5
2. The AF motor drive unit 53, the distance measuring sensor 54, and the DX terminal 55 are connected.

The camera CPU 40 is a microcomputer that controls all the operations (photometry, distance measurement, exposure operation, etc.) of the camera body 10, and has a built-in processor and rewritable memory (RAM 40a and flash memory 40b). The camera CPU 40 operates according to a program stored in the flash memory 40b. Camera body 10
Is shipped as a product with the program for the silver halide film camera stored in the flash memory 40b. The program stored in the flash memory 40b is rewritten as necessary, as described later in detail. Data is temporarily stored in the RAM 40a.

The display section 41 is a section for displaying the state of the camera, and is a liquid crystal display section arranged on the upper surface of the camera body 10. The photometry unit 42 and the light control unit 43 obtain information on the exposure of the camera. The camera CPU 40 performs the exposure calculation based on the information. The lens 44 is a replaceable lens mounted on the camera body 10. Camera CPU 40
Can communicate with the control circuit in the lens 44 to obtain information such as aperture information and focal length information of the lens 44. The external flash 45 is a removable flash that is attached to the accessory shoe of the camera body 10. As described above, the adjustment terminal 46 is a communication portion with an external device (a machine for adjusting when assembling the camera body 10, the back cover 20, or the digital back 30). E
^The 2PROM 47 stores data such as adjustment values and correction values of the camera body 10. DC / DC converter 4
8 keeps the voltage of the power source supplied from the battery 49 constant. The battery check circuit 59 checks whether the battery 49 is usable.

The diaphragm drive unit 51 controls the diaphragm so that it has a set value during exposure. The shutter / mechanical charge unit 52 controls the shutter speed to be set at the time of exposure, moves the mirror up and down, and prepares the mechanical unit for the next exposure. The AF motor drive unit 53 drives the lens 44 based on the distance measurement start signal. The distance measuring sensor 54 is arranged in the distance measuring module and detects the focus position of the subject based on the distance measuring start signal. The DX terminal 55 is used as a terminal for reading film information such as film sensitivity and the number of sheets, and also used as a terminal for data communication with the digital back 30, and is also a terminal for detecting mounting of the digital back 30.

The switches 50 are S1, S2 and SCMA.
Includes IN, SRC, SCPU / DOWN, SISO.
S1 is a switch for starting the distance measuring and photometric operations. S2 is a switch for starting the exposure of the camera. SCMAIN is a switch that controls the power supply of the camera. The SRC is a switch that detects opening / closing of the back cover 20 or the digital back 30 attached to the camera body 10. SCUP / DOWN is a switch for changing camera settings (shutter speed, aperture, ISO, etc.). SISO uses SCUP when changing ISO
The switch is operated in conjunction with / DOWN.

FIG. 2 is a circuit block diagram of the digital back 30.

D for controlling the control system of the digital back 30
-The CPU 60 includes an electronic image pickup unit 61 including a CCD, SD
RAM 62, memory card 63, liquid crystal monitor 34, switches 64, communication terminal 65, DC / DC converter 6
6. A flash memory 67 is connected.

The D-CPU 60 converts the image data from the electronic image pickup section 61 including a CCD, and the known SDRAM 6
2 or memory in a memory card 63 (for example, CompactFlash (registered trademark) or smart media) which is a small-sized removable recording medium, and the captured image data is displayed on the screen of the liquid crystal monitor 34. Play. Further, the communication terminal 65 is used to communicate with the camera body 10.

The D-CPU 60 uses the communication data from the camera body 10 to set DC / DC in the digital back 30.
The converter 66 is used to control the supply of power, control the timing of capturing image data during exposure, and control the screen display of the liquid crystal monitor 34. DC
The PU 60 operates according to a program stored in the rewritable flash memory 67. The flash memory 67 stores a digital camera program for the camera body 10 to operate as a digital camera, individual difference information regarding the digital back 30 (size information regarding the size of the image sensor), and the like.

The switches 64 are SDMAIN and SPL.
Includes AY, SDUP / DOWN, SREC, SMODE. The SDMAIN is a switch that controls the power supply of the digital back 30. SPLAY is a switch for reproducing a captured image. SREC is a switch that enables digital exposure. SDUP / DOW
N is a switch for changing the contents of the digitally photographed image (for example, changing the page of the photographed image or changing information of the photographed image). SMOD
E changes the information of the captured image by SDUP / DOW
It is a switch operated in conjunction with N. SDUP / D
With the exception of OWN, these switches consist of a rotary dial with four positions.
One is always selected.

FIG. 3 is a block diagram of the focus detection device. A main mirror 6 is arranged in the center of the camera body 10 with an inclination of about 45 degrees with respect to the optical axis 4. A sub mirror 7 is arranged behind the main mirror 6 so as to form an angle of about 90 degrees with the main mirror 6. At the time of exposure, the main mirror 6 and the sub mirror 7 are retracted upwards,
The focusing lens 5 forms a subject image on the film surface 8. An AF sensor module 9 is arranged below the sub mirror 7. A part of the light flux from the subject 2 passes through the main mirror 6. The sub mirror 7 guides the transmitted light flux to the AF sensor module 9.

FIG. 4 shows the structure of the AF sensor module 9. The infrared component of the light flux from the subject 2 is cut by the filter 9a, passes through a specific diaphragm by the condenser lens 9b and the diaphragm mask 9d, and is divided into two. On the way, the optical path is bent by the mirror 9c. The two separated light fluxes are imaged on the standard portion and the reference portion on the CCD sensor 9f by the separator lens 9e.
The camera CPU 40 calculates a relative shift amount (defocus amount) between these two images, converts the defocus amount into a lens driving amount, drives the focusing lens 5, and performs focus detection.

FIG. 5 shows a finder display 70 when the back cover 20 is attached to the camera body 10. The viewfinder display 70 is visible through the viewfinder window 18 of the camera body 10. The diagonal lines in the figure are dark areas. A wide focus frame 75 and a spot photometry circle 73 are displayed in a portion 77 where the shooting range can be seen. In this portion 77, a total of nine distance measuring areas including a central distance measuring area 72 and upper, lower, left, right and further outer distance measuring areas 74 are arranged. Below this portion 77, an information display unit 76 for displaying information such as shooting conditions is arranged.

When the digital back 30 is attached to the camera body 10, the shooting range is displayed in the viewfinder display 70 as shown in FIG. The parts 77, 78, 79 in which is visible are provided. FIG. 6 shows a reference frame V to be compared with the screen size of the photographable range when selecting the portions 77, 78, 79 in which the photographing range shown in FIG. 7 is visible.
1, V2 and V3 are shown.

That is, the camera CPU 40, based on the size information obtained by communicating with the digital back 30 when the digital back 30 is attached to the camera body 10,
The screen size S of the photographable range is set to reference frames V1, V2, V3.
Screen size S1 (a1, b1), S2 (a2, b
2) and S3 (a3, b3).

When the screen size S is S1 (a1, b1) or more, a portion 77 where the photographing range can be seen as shown in FIG. 7A.
Is displayed. This is the same as when the back cover 20 is attached to the camera body 10.

If the screen size S is S2 (a2, b2) or more,
When it is less than S1 (a1, b1), a portion 78 where the photographing range is visible is displayed as shown in FIG. 7 (b).

If the screen size S is S3 (a3, b3) or more,
When it is less than S2 (a2, b2), a portion 78 where the photographing range is visible is displayed as shown in FIG. 7C.

Further, according to the screen size S, the distance measuring area used for auto focus is selected.

When the screen size S is S1 (a1, b1) or more, all nine distance measuring areas are used.

The screen size S is S2 (a2, b2) or more,
When it is less than S1 (a1, b1), a total of 5 distance measuring areas at the center, top, bottom, left and right are used, and the outer 4 distance measuring areas are automatically excluded.

If the screen size S is S3 (a3, b3) or more,
When it is less than S2 (a2, b2), total 3 in the center and left and right
The distance measuring areas of points are used, and the distance measuring areas of the upper and lower two points and the outer four points are automatically excluded.

When the screen size S is less than S3 (a3, b3), only one point in the central distance measuring area is used and the other eight distance measuring areas are automatically excluded.

When the screen size becomes smaller, a distance measuring area that does not fall within the shooting range appears. Since it is not preferable to focus on the distance measuring area outside the photographing range in this way, the distance measuring area to be used is limited as described above. However, the distance-measuring areas that are automatically excluded may be manually selected and used.

The selected state of the distance measuring area used for autofocus is displayed on the distance measuring display section 80 of the display section 41 shown in FIG.

FIG. 9 is a display example of the distance measuring display unit 80.
When using the nine distance measuring areas, the display 82 shown in FIG. When using a total of five distance measuring areas in the center and in the upper, lower, left and right, the display 83 shown in FIG. 9B is obtained. When using a total of three distance measurement areas in the center and left and right, FIG.
The display 84 of (c) is displayed.

Next, the digital back 3 of the camera body 10
The operation of the camera when 0 is attached will be described.

As shown in the flow charts of FIGS. 17 and 18, first, it is determined whether or not the digital back cover is attached (# 1). If it is not attached, the normal distance measurement area range display is performed (# 5A).

If it is attached, the process proceeds to screen size determination (# 2). The screen size S is S3 (a shown in FIG.
If it is smaller than 3, b3), only the central distance measuring area 72 is used (# 5D).

If the screen size S is S3 (a3, b3) or more,
When the judgment of less than S2 (a2, b2) is satisfied (YES in # 3), the display of FIGS. 7C and 9C is performed (#
5C). At this time, in the following processing, the data of group 3 including a total of three distance measuring areas on the center and left and right are used.

If the screen size S is S2 (a2, b2) or more,
When the judgment of less than S1 (a1, b1) is satisfied (YES in # 4), the display of FIG. 7 (b) and FIG. 9 (b) is performed (#
5B). At this time, in the following processing, the data of group 2 including a total of five distance measuring areas in the center and in the upper, lower, left and right directions is used.

When the above conditions are not satisfied (Y in # 4)
ES), FIG. 7 (a) and FIG. 9 (a) are displayed (# 5
A). At this time, in the following processing, the data of group 1 including a total of 9 distance measuring areas including the center, top, bottom, left and right, and 4 points outside thereof are used.

When an AF start signal is input from the outside (release button or the like), the camera CPU 40 outputs a charge accumulation start signal to the distance measuring module, and the distance measuring sensor 54 of the distance measuring module stores the charge accumulation. Start (# 6A, #
6B, # 6C, # 6D). When the charge accumulation of the distance measuring sensor 54 is completed, the camera CPU 40 causes the distance measuring sensor 54 to
A charge read start signal is output to, the accumulated charge amount signal output from the distance measuring sensor 54 is captured, A / D converted, and stored in the memory 40a in the camera CPU 40 (# 7A, # 7B, # 7C). , # 7D). Next, a predetermined distance measurement calculation is performed using the data stored in the memory 40a, and the focus shift amount on the film equivalent surface, that is, the defocus amount (Df) is calculated (# 8A, # 8B, # 8).
C, # 8D).

For screen sizes smaller than S3 (a3, b3), after the defocus amount is calculated, the center selection algorithm process for selecting the center distance measuring area is performed (# 9).
D). For a screen size of S3 (a3, b3) or larger, multipoint selection algorithm processing (details will be described later) is performed (# 9A, # 9B, # 9C).

Next, an instruction is given to the photometric module to detect the amount of received ambient light (# 10A, # 10B, # 10).
C, # 10D), an exposure calculation for obtaining an exposure value based on the obtained amount of received light and distance measurement information (details will be described later).
Is performed (# 11A, # 11B, # 11C, # 11D).
In steps # 11A, # 11B, and # 11C, the exposure is calculated by weighting a plurality of photometric areas, as will be described later. In step # 11D, the exposure is calculated based on only the data of the central photometric area.

Next, according to the calculated defocus amount,
It is determined whether the image is in focus (# 12). If it is determined to be in focus (YES in # 12), the AF operation is completed and the AF is locked (# 16), and the focus area is displayed (# 17). If out of focus (NO in # 12),
Convert the defocus amount into the drive amount of the AF lens (# 1
4), the lens is driven to perform the operation of focusing (# 15), and the next distance measurement is started (# 6A, # 6B, #
6C, # 6D). The AF operation is completed by repeating the above operation until focusing is achieved.

19 to 21 show a first example of the multi-point selection algorithm processing. Three different multi-point selection algorithm processes are performed according to the screen size. The multi-point selection algorithm 1 selects the closest distance measuring area from the nine distance measuring areas of group 1, and further preferentially selects the distance measuring area on the upper side of the screen. The multi-point selection algorithm 2 selects the closest distance measuring area from the five distance measuring areas of group 2, and preferentially selects the upper area of the screen.
The multipoint selection algorithm 3 selects the closest distance measurement area from the three distance measurement areas of group 3.

In the following, as shown in FIG. 10, the area used for the multipoint selection algorithm processing is made to correspond depending on whether the camera is in the horizontal position or the vertical position. FIG. 10A shows the case of the normal lateral position. FIG.10 (b) shows the case of a vertical position with the grip on top. FIG. 10C shows a vertical position with the grip down. That is, in the following description, with respect to the nine distance measuring areas, the columns arranged on the left, the center, and the left are L, C, and R, and the subscript i is added to the upper, central, and lower rows.
+1, i, i-1 are used.

FIG. 19 shows steps # 5A to # 5 of FIG.
9A is a detailed flowchart of the multipoint selection algorithm 1 using the distance measurement areas of group 1;

First, it is determined whether the camera is in the horizontal position or the vertical position, and the defocus amount (Df (X)) is substituted for each area (# 21). Next, it is determined whether or not distance measurement detection is impossible in all areas i and i + 1 (# 22). If it is determined to be impossible (YES in # 22), the closest area is selected from the i-1 areas (# 24).

On the other hand, when there is an area where distance measurement can be detected in the areas i and i + 1 (NO in # 22), the area Xj closest to the area i and i + 1 is temporarily selected (# 2).
3). Next, it is determined whether j and i are equal (# 25), and j
And i are different (NO in # 26), Xj is selected (# 28). When j is equal to i (YE in # 25
S), the difference between the defocus amounts of Xi and the area Xi + 1 immediately above Xi is calculated, and it is determined whether the absolute value of this difference is smaller than a predetermined value γ (# 26). If it is smaller than γ (# 2
If YES in step 6), Xi + 1 is selected (# 27). When the absolute value of the difference between the defocus amounts of Xi and the area Xi + 1 immediately above Xi is larger than the predetermined value γ (NO in # 26),
Xj is selected (# 28).

FIG. 20 shows steps # 5B to # 5 of FIG.
9B is a detailed flowchart of the multi-point selection algorithm 2 using the range-finding area of group 2 in 9B.

First, it is determined whether the camera is in the horizontal position or the vertical position, and the defocus amount (Df (X)) is substituted for each area (# 29). Next, in group 2, Ci-1
It is determined whether or not all the areas except for the distance measurement cannot be detected (# 10). When the distance measurement cannot be detected in all areas except Ci-1, (YES in # 10), Ci-1 is selected (# 32).

On the other hand, if there is an area where distance measurement can be detected in areas other than Ci-1, the nearest area Xj is temporarily selected (# 31). Next, Xj and C
It is determined whether i is equal (# 33), and when Xj and Ci are different (NO in # 33), Xj is selected (# 36). X
When j and Ci are equal (YES in # 33), Ci and C
The difference in defocus amount from the area Ci + 1 immediately above i is calculated, and it is determined whether or not the absolute value of this difference is smaller than a predetermined value γ (# 34). If smaller than γ (YE in # 34
S) and Ci + 1 are selected (# 35). When the absolute value of the difference in the defocus amount between Ci and the area Ci + 1 immediately above Ci is larger than the predetermined value γ (NO in # 34), Xj is selected (# 36).

FIG. 21 shows steps # 5C to # 5 of FIG.
9C is a detailed flowchart of the multipoint selection algorithm 1 using the distance measurement areas of group 3;

It is determined whether the camera is in the horizontal position or the vertical position, the defocus amount (Df (X)) is substituted for each area (# 37), and the area closest to the group 3 is selected (# 38). .

22 to 24 show a second example of the multipoint selection algorithm processing. Depending on the screen size and subject magnification,
Three different types of multi-point selection algorithm processing are performed.

FIG. 22 shows steps # 5A to # 5 of FIG.
9A is a detailed flowchart of the multipoint selection algorithm 1 using the distance measurement areas of group 1;

It is determined whether the camera is in the horizontal position or the vertical position, and the defocus amount (Df (X)) is substituted for each area (# 41). It is determined whether or not the subject magnification β (Ci) of the area Ci is larger than the predetermined value β1 (# 42), and if it is larger (YES in # 42), the area closest to the group 2 is selected (# 44). Subject magnification β (Ci) is a predetermined value β
If it is 1 or less (NO in # 42), the area closest to the group 1 is selected (# 43).

FIG. 23 shows steps # 5B to # 5 of FIG.
9B is a detailed flowchart of the multi-point selection algorithm 1 using the range-finding area of group 2 in 9B.

It is determined whether the camera is in the horizontal position or the vertical position, and the defocus amount (Df (X)) is substituted for each area (# 45). It is determined whether or not the subject magnification β (Ci) of the area Ci is larger than a predetermined value β2 (# 46), and if it is larger (YES in # 46), Ci is selected (# 48). β
When (Ci) is less than or equal to the predetermined value β2 (NO in # 46),
The closest area from group 2 is selected (# 47).

FIG. 24 shows steps # 5C to # 5 of FIG.
9C is a detailed flowchart of the multipoint selection algorithm 1 using the distance measurement areas of group 3;

It is determined whether the camera is in the horizontal position or the vertical position, the defocus amount (Df (X)) is substituted for each area (# 49), and the area closest to the group 3 is selected (# 50). .

The multi-point selection algorithm is not limited to the above-mentioned first and second examples, but various modes can be adopted. For example, it is possible to combine the first example and the second example described above.

Next, the exposure calculation will be described.

As shown in FIG. 11, the photometric module has a multi-division photometric area. 0 is the area other than 1 to 13,
1 to 13 meter the respective parts.

FIG. 12 shows distance measuring areas 72, 74a to 74a.
The relationship between h and the photometric area is shown.

FIG. 13 shows distance measuring areas 72, 74a to 74a.
h is classified into three groups A, B, and C.
For example, when the distance measurement area selected by the multipoint selection algorithm processing of FIGS. 17 and 18 belongs to group A,
Light is detected in the photometric area 6 in FIG. Similarly, when it belongs to group B, it is detected in the photometric area 7, and when it belongs to group C, it is detected in the photometric area 8.

In the exposure calculation, the weighting of the photometric area corresponding to the distance measuring area is increased, and the control is performed with emphasis on the brightness of the subject. Ambient light Main subject brightness value BVA0H
Is calculated by the following equation.

[Equation 1]

Here, Wti is a weight and SiH is a luminance value of each photometric area.

Steps 11A, # 11B and # 1 of FIG.
In the exposure calculation algorithm of 1C, different weighting is applied to the photometric area corresponding to the selected distance measuring area according to the screen size. In the case of the same angle of view, the number of photometric regions occupied by the main subject decreases as the screen size decreases, so the weighting around the main subject is reduced and the photometric regions used for calculation are limited.

In exposure calculation algorithm 1 (step # 11A in FIG. 17), the weight of the photometric area corresponding to the selected distance measuring area is 4, the weight of the adjacent photometric area is 3, and the weights of the remaining photometric areas are set. Set to 1. FIG. 14A shows an example in which the selected distance measuring area belongs to group A.
The weight of the photometric area 6 is 4, the weight of the photometric areas 5 and 7 is 3, and the weights of the other photometric areas are 1.

In the exposure calculation algorithm 2 (step # 11B in FIG. 17), out of the photometric areas 0 to 13, the areas other than the photometric areas 5 and 9 are targeted, and the photometric areas corresponding to the selected range-finding area are targeted. It is assumed that the weight of the area is 4, the weight of the adjacent photometric area is 2, and the weights of the remaining photometric areas are 1.
FIG. 14B shows an example in which the selected distance measuring area belongs to group A. The weight of the photometric area 6 is 4, the weight of the photometric area 7 is 2, and the weights of the other photometric areas are 1. When belonging to the group B, the weight of the photometric area 7 is 4, the weight of the photometric areas 6 and 8 is 2, and the weights of the other photometric areas are 1. If you belong to group C,
The weight of the photometric area 8 is 4, the weight of the photometric area 7 is 2, and the weights of the other photometric areas are 1.

In exposure calculation algorithm 3 (step # 11C in FIG. 17), only the photometric areas 6 to 8 of the photometric areas 0 to 13 are targeted, and the weight of the photometric area corresponding to the selected distance measuring area is set. 4, the weight of the remaining two photometric areas is set to 1. FIG. 14C shows an example in which the selected distance measuring area belongs to the group A. The photometric area 6 has a weight of 4, and the photometric areas 7 and 8 have a weight of 1. When belonging to the group B, the weighting of the photometric area 7 is set to 4, and the weighting of the photometric area 6 and the photometric area 8 is set to 1. In the case of belonging to the group C, the weighting of the photometric area 8 is 4, and the weighting of the photometric areas 6 and 7 is 1.

As described above, when the case back (digital back) equipped with the electronic image pickup device is attached, communication is performed between the digital back and the camera, and the size information of the electronic image pickup device is taken into the camera. . Based on this size information, by changing the algorithm and display of multi-point photometry and multi-point photometry, the optimal photometry area is used regardless of the size of the light receiving surface of the image sensor of the electronic image pickup device. The distance measurement operation can be performed.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a camera body according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram of a digital back according to an exemplary embodiment of the present invention.

3 is a configuration diagram of a focus detection device of the camera body of FIG.

FIG. 4 is a configuration diagram of an AF module of the focus detection apparatus in FIG.

FIG. 5 is an explanatory diagram of a finder display.

FIG. 6 is an explanatory diagram of a reference frame.

FIG. 7 is an explanatory diagram of switching of viewfinder display.

FIG. 8 is an explanatory diagram of a display unit.

FIG. 9 is an explanatory diagram of a display on a distance measurement display unit.

FIG. 10 is an explanatory diagram of areas used in a multipoint selection algorithm.

FIG. 11 is a layout view of a multi-division photometric area.

FIG. 12 is an explanatory diagram of a relationship between a photometry area and a distance measurement area.

FIG. 13 is an explanatory diagram of grouping of distance measurement areas.

FIG. 14 is an explanatory diagram of weighting of a photometric area.

FIG. 15 is a rear view of the camera when used as a silver salt film camera.

16 is a rear view of the camera when the back cover of the camera of FIG. 15 is replaced with a digital back.

FIG. 17 is a flowchart of AF operation of the camera.

FIG. 18 is a continuation of the flowchart of FIG.

FIG. 19 is a flowchart of the multipoint selection algorithm 1 of the first example.

FIG. 20 is a flowchart of a multipoint selection algorithm 2 of the first example.

FIG. 21 is a flowchart of the multipoint selection algorithm 3 of the first example.

FIG. 22 is a flowchart of the multipoint selection algorithm 1 of the second example.

FIG. 23 is a flowchart of a multipoint selection algorithm 2 of a second example.

FIG. 24 is a flowchart of a multipoint selection algorithm 3 of the second example.

[Explanation of symbols]

10 camera body 20 case back 30 digital back 40 CPU (focus control unit, exposure control unit, display control unit) 41 Display 42 Metering unit (multipoint metering unit) 46 Adjustment terminal (receiver) 54 Distance measuring sensor (multipoint distance measuring section) 61 Electronic Imaging Unit (Electronic Imaging Device) 72, 74, 74a to 74h Distance measuring area

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 17/18 H04N 5/232 H 5C022 17/48 5/235 H04N 5/225 101: 00 5/232 G02B 7/11 N 5/235 D // H04N 101: 00 G03B 3/00 A (72) Inventor Norihiko Akamatsu 2-3-13 Azuchi-cho, Chuo-ku, Osaka-shi, Osaka Osaka Kokusai Building Minorta F-term ( Reference) 2H002 DB14 DB32 GA73 HA04 JA07 2H011 BA31 BB03 DA00 DA05 2H051 BA41 DA08 EB20 EC01 GA03 GA10 GA17 2H102 AA44 BA01 BB09 2H104 AA18 5C022 AA13 AB02 AB27 AC12 AC42 AC69

Claims (3)

[Claims] 1. A camera, which can be used as a digital camera by replacing a back cover when used as a silver-salt film camera with a digital back equipped with an electronic image pickup device, in each of a plurality of ranging areas. A multi-point distance measuring unit that outputs distance measuring information that is a result of detecting the distance to the distance, and a focus control unit that controls the focal position of the lens based on the distance measuring information output by the multi-point distance measuring unit. A receiving unit that receives size information regarding the size of the light receiving surface of the image pickup element of the electronic image pickup device from the digital back, the focus control unit based on the size information received by the receiving unit, A camera characterized by changing an algorithm for controlling a focal position of a lens. 2. A multi-point photometric unit that outputs photometric information that is a result of detecting the brightness of a subject for each of a plurality of photometric regions, and an exposure is controlled based on the photometric information that the multipoint photometric unit outputs. The camera according to claim 1, further comprising: an exposure control unit, wherein the exposure control unit changes an algorithm for controlling the exposure based on the size information received by the reception unit. 3. A display unit for displaying selection of the distance measuring area, and a display control unit for changing the display displayed by the display unit based on the size information received by the receiving unit. Camera according to claim 1 or 2, characterized in that