JPH1138313A - Optical device and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate complicated operation such as focusing on a main object for several times at the time of performing photographing, in which the depth of field is given priority, and to prevent a deeper depth and a longer exposure time than needed. SOLUTION: As the outline operation of a camera, distance inside a screen and the two-dimensional distribution of defocusing quantity are firstly measured (a step 101 as a distribution information measuring means). Next, the inside of the screen is divided into plural subject areas based on distribution information, and one or more main subject areas are, at least, detected from the plural subject areas (the step 102 as an area detecting means). Then, the focal position of an optical system and a diaphragm are adjusted so as to make the entire area of the main subject area detected in a focused state (the steps 103-106 as adjusting means).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an optical device and a camera having automatic focus adjustment and depth adjustment functions.

[0002]

2. Description of the Related Art In a camera having an automatic exposure adjustment function and an automatic focus adjustment function, a photographing mode in which priority is given to the depth of field is disclosed in Japanese Patent Publication No. 7-82180.
This makes it possible to take a picture so that all the subjects intended by the photographer are in focus. If the camera has only one focus detection area, the camera automatically focuses on each of the frontmost and farthest subjects. Focusing is performed using a focus adjustment function, and the camera automatically sets an optimum photographing focus position and aperture based on the luminance of the field at that time and the depth difference between the two subjects.

On the other hand, in a camera having a plurality of focus detection areas, the photographing operation is simplified to a single operation by using the detection results of the front and back from the plurality of focus detection areas. Is known.

On the other hand, a technique for optically measuring the distance to an object existing in a plurality of directions has been disclosed by the present applicant in Japanese Patent Application Laid-Open Publication No. Hei.
67607. This is a technique in which, after obtaining distance distribution information of an object present in an object scene, an area where the main subject exists in the object scene is estimated based on the distance distribution information of the object.

Here, a typical method of estimating a main subject area, which has been conventionally performed, will be described.

The scene of FIG. 17A is photographed by a stereo camera using a CCD or the like. Two images with parallax obtained by a stereo camera are referred to as “m
Xn blocks. When a well-known correlation operation is performed between a signal in one block of one image and a signal in a corresponding block captured by the other camera, the distance and data to an object in the previous block are calculated according to the principle of triangulation. Focus can be measured. By performing this measurement for all blocks, distance distribution information composed of “m × n” blocks as shown in FIG. 17B is obtained.

Next, region division (grouping) is performed in order to separate each object constituting the scene on the screen. When the grouping is performed, the object space composed of the aforementioned “m × n” blocks is divided into regions for each object as shown in FIG. (The shaded area in the figure is an area where the reliability of the correlation operation result is determined to be low due to insufficient contrast of the image signal, etc.) As a method of area division (grouping), the blocks constituting the object space and There is a method of comparing the similarity between two parameters related to a block adjacent thereto, and discriminating the same object if the similarity is high and the different object if the similarity is low. Information used as the parameter,
In the case where dense distance distribution data is obtained, it is often a normal vector of a surface, and in the case of relatively rough distance distribution data as in this conventional example, a distance value or a defocus value is simply used. .

For example, with respect to the distance information of each block in FIG. 17B, the distance information of two adjacent blocks is compared. Are determined to form the same object ", and if the distance difference is greater than a predetermined threshold, it is determined that" the objects forming the two blocks are different objects ". By performing the above-described determination between all blocks and blocks adjacent to each other, the entire screen can be divided into regions for each object, and each divided region is treated as a group representing one object be able to.

Next, the characteristics of each region (each group) constituting the photographing space are evaluated, and a group representing the main subject is determined from all the groups.

For example, in the case of FIG.
For each of the groups 7, characteristics such as an average distance, an area width, a height, and a position on a screen are respectively calculated, and comprehensive evaluation is performed to determine an area considered as a main subject.

For example, a main subject degree evaluation function as shown in the following equation (1) can be considered.

(Main subject degree) = W ₁ × (width) × (height) + W ₂ / (distance from center on screen) + W ₃ (average distance) (1) In the above equation (1), W ₁ , W ₂ and W ₃ are weighting constants, the distance from the center of the screen is the distance between the center of the screen and the position of the center of gravity of the area, and the average distance represents the average distance of all blocks in the area. The main subject degree is calculated for all areas, and the subject having the highest main subject degree is determined as the main subject.

After one focus adjustment distance is determined based on the distance information in the main subject area so as to focus on the next area determined as the main subject, the lens is driven to focus.

[0014]

By the way, in the depth of field priority photographing mode in which the camera has only one focus detection area, the photographing method focuses on the subject a plurality of times as described above. However, it was troublesome for beginner level photographers.

On the other hand, even if a plurality of focus detection areas are provided, if the focus detection area does not match the position of the subject to be actually focused, the depth becomes unnecessarily deep or the exposure time becomes longer, which may cause camera shake. And so on.

(Object of the Invention) A first object of the present invention is to eliminate the troublesome operation of focusing on a main object a plurality of times and to prevent the depth from becoming deeper than necessary. It is an object of the present invention to provide a possible optical device.

A second object of the present invention is to provide an optical device capable of changing the number of main target areas automatically set to the number of areas reflecting the intention of the photographer, if necessary. Is what you do.

A third object of the present invention is to eliminate the troublesome operation of having to focus on a main subject a plurality of times when performing depth of field priority photographing, and
It is an object of the present invention to provide a camera capable of preventing an unnecessarily deep depth and a long exposure time.

A fourth object of the present invention is to change the number of main subject areas automatically set to the number of areas reflecting the intention of the photographer, if necessary, to reflect the intention of the photographer. It is an object of the present invention to provide a camera capable of performing depth-of-field priority shooting.

[0020]

In order to achieve the first object, according to the present invention, there is provided a distribution information measuring means for measuring a two-dimensional distribution of a distance or a defocus amount in a screen. Area detecting means for dividing the screen into a plurality of target areas based on the distribution information and detecting at least one or more main target areas from the plurality of target areas, and focusing on the entire detected main target area This is an optical device having adjusting means for adjusting the focal position of the optical system and the aperture so as to be in a state.

In order to achieve the second object,
According to a second aspect of the present invention, an operation member for changing the number of main target areas by an external operation with respect to the main target areas detected with ranking automatically detected by the area detecting means is provided. Optical device.

Also, in order to achieve the third object,
The present invention according to claims 4 to 8, wherein a distribution information measuring means for measuring a two-dimensional distribution of a distance or a defocus amount in a screen,
An area detecting unit that divides the screen into a plurality of subject areas based on the distribution information, and detects at least one main subject area from the plurality of subject areas; and In this case, the camera has an adjusting means for adjusting the focal position of the optical system and the aperture.

In order to achieve the fourth object,
According to a fifth aspect of the present invention, there is provided an operating member for changing the number of main subject areas by an external operation with respect to the main subject areas detected in order automatically detected by the area detecting means. Camera.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

Taking the depth-of-field priority shooting mode of the automatic focusing camera as an example, the number of main subject area candidates can be arbitrarily changed using a uniaxial rotary operation member (so-called dial) for the main subject automatic selection result. The first embodiment of the present invention of the system will be described in detail below.

FIG. 1 is a block diagram of basic components of a camera according to the first embodiment of the present invention.

In the figure, 51 is a distance distribution measuring section for measuring the distance of an arbitrary place in the scene, 52 is a main subject area detecting section for detecting an area where the main subject is present in the photographing screen, and 5.
3 is a main subject area number changing member for changing the number of main subject areas automatically determined by the main subject area detecting means 52 in accordance with a manual input. Focusing distance determination unit,
55 is a photometric means for measuring the brightness of the subject, 57 is a depth of field determining unit for obtaining a necessary depth of field from the focus adjustment information for each of the main subject regions detected by the main subject region detecting unit 52, and 56 is Depth of field necessary for photographing obtained by the depth of field determination unit 57 and the photometric unit 55
A shutter speed determining unit that determines a shutter speed when actually taking a picture from the luminance information obtained in step 5, a photographing optical system 59, a lens driving device 58 that drives a lens to adjust the focus, and a dotted line 60 Indicates an area embodied by the CPU and the RAM and the ROM of the microcomputer. Among them, the distance distribution measuring unit 51 and the photometric unit 55 are embodied by the microcomputer and the measuring optical system, and the main subject area number changing member 53 is embodied by the microcomputer and the operating member. It is an expression.

The detailed operation of each unit and the flow of the entire processing will be described below with reference to FIG.

When the photographer presses a shutter button (not shown) or the like, the photographing process is started via step (100).

In step (101), a subroutine for measuring the distance distribution of the object scene by the distance distribution measuring unit 51 is called. The measurement of the distance distribution is performed by an optical system and a microcomputer. Hereinafter, the configuration of the optical system and the contents of the subroutine executed by the microcomputer will be described.

FIG. 3 is a view showing the arrangement of optical components of a camera for detecting the distance of the field. In FIG. 3, reference numeral 1 denotes a photographing lens, 8 denotes a field lens, 9 denotes a secondary imaging lens,
Is an area sensor.

Two photographing screens 1 of the area sensor 10
Light beams from different pupil positions of the photographing lens 1 are respectively guided onto 0a and 10b, and are re-imaged at an imaging magnification determined by the field lens 8 and the secondary imaging lens 9. The area sensor 10 is located at a position optically equivalent to the photographic film surface with respect to the photographic lens 1, and has a photographic screen 10a,
0b has a field of view equal to a part of the photographing screen or the photographing screen.

FIG. 4 shows a layout when the detection optical system shown in FIG. 3 is suitable for a camera.
6 is a quick return mirror, 18 is a pentaprism,
19 is a split prism, 20 is a reflection mirror and the others are shown in FIG.
Is the same as

FIG. 5 is a view of the layout of FIG. 4 as viewed from above the camera.

With the above configuration, the photographed images 10a and 10b having a predetermined parallax can be obtained.

The camera having the above configuration is disclosed in detail in Japanese Patent Application No. 5-278433.

FIG. 6 is a circuit diagram showing an example of a specific configuration of a camera having the above-described components. First, the configuration will be described.

In FIG. 6, PRS is a camera control device, for example, a CPU (central processing unit), ROM,
It is a one-chip microcomputer having a RAM and an A / D conversion function. The camera control device (hereinafter referred to as a microcomputer) PRS performs a series of camera operations such as an automatic exposure control function, an automatic focus adjustment function, and film winding / rewinding in accordance with a camera sequence program stored in a ROM. Is going. For that, the microcomputer PRS
Communication signals SO, SI, SCLK, communication selection signal CKC
By using M, CDDR, and CICC, communication is performed with a peripheral circuit in the camera body and a control device in the lens to control each circuit and lens.

SO is a data signal output from the microcomputer PRS, SI is a data signal input to the microcomputer PRS, and SCLK is a synchronous clock of the signals SO and SI.

LCM is a lens communication buffer circuit,
When the camera is in operation, power is supplied to the lens power supply terminal VL and a selection signal C from the microcomputer PRS is supplied.
When the LCM is at a high potential level (hereinafter, abbreviated as “H” and the low potential level is abbreviated as “L”), communication between the camera and the lens is buffered.

When the microcomputer PRS sets CLCM to "H" and sends out predetermined data from the SO in synchronization with SCLK, the lens communication buffer circuit LCM causes each of SCLK and SO to pass through the camera-lens communication contact. The buffer signals LCK and DCL are output to the lens. At the same time, a buffer signal of the signal DLC from the lens is output to the SI, and the microcomputer PRS synchronously inputs lens data from the SI.

DDR is a detection and display circuit for various switches SWS, which is selected when the signal CDDR is "H", and is controlled by the microcomputer PRS using SO, SI and SCLK. That is, based on data sent from the microcomputer PRS, the display of the display member DSP of the camera is switched, and the on / off state of various operation members of the camera is notified to the microcomputer PRS by communication. The state of the rotation operation member, which is the main subject region number changing member in the present embodiment, is also detected here.

OLC is an external liquid crystal display device located above the camera, and ILC is a finder internal liquid crystal display device.

SW1 and SW2 are switches linked to a release button (not shown). The switch SW1 is turned on when the first step of the release button is pressed, and subsequently the switch SW2 is turned on when pressed in the second step. The microcomputer PRS performs photometry and automatic focus adjustment when the switch SW1 is turned on, and performs exposure control and subsequent film winding with the switch SW2 turned on as a trigger.

The switch SW2 is connected to the "interrupt input terminal" of the microcomputer PRS. Even when the program is executed when the switch SW1 is turned on, an interrupt is generated by turning on the switch SW2, and the control is immediately transferred to a predetermined interrupting program. Can be.

MTR1 is for film feeding, MTR2 is for mirror up / down and shutter spring charging,
Each is a motor, and each drive circuit MDR1, MD
R2 controls normal rotation and reverse rotation. Microcomputer PR
Signals M1F, M1R, M2F, and M2R input from S to the drive circuits MDR1 and MDR2 are motor control signals.

MG1 and MG2 are shutter start curtain / rear curtain run start magnets, respectively, which are energized by signals SMG1 and SMG2 and amplification transistors TR1 and TR2,
Shutter control is performed by RS.

The motor drive circuits MDR1, MDR2,
Since the shutter control does not directly relate to the present invention, a detailed description is omitted.

A signal DCL input to the in-lens control circuit LPRS in synchronization with LCK is transmitted from the camera to the lens LNS.
, And the operation of the lens in response to the command is determined in advance. This in-lens control circuit LPR
S analyzes the command in accordance with a predetermined procedure, and performs operations of focus adjustment and aperture control, the operation status of each part of the lens (driving status of focus adjustment optical system, driving status of aperture, etc.) from output DLC, and various parameters. (Open F-number, focal length,
It outputs distance information such as the defocus amount versus the coefficient of the movement amount of the focus adjustment optical system, various focus correction amounts, and the like.

In this embodiment, a zoom lens is shown as an example. When a focus adjustment command is sent from a camera, a focus adjustment motor LTMR is sent to a signal KMF in accordance with the drive amount and direction sent at the same time. , LMR to adjust the focus by moving the optical system in the direction of the optical axis.
The amount of movement of the optical system is monitored by a pulse signal SENCF of an encoder circuit ENCF that detects a pattern of a pulse plate that rotates in conjunction with the optical system with a photocoupler and outputs a number of pulses corresponding to the amount of movement. The coefficient is calculated by a counter in the internal control circuit LPRS, and when the predetermined movement is completed, the LPRS itself sets the signals LMF and LMR to 'L' to brake the motor LMTR.

For this reason, once the camera focus adjustment command is sent, the microcomputer PRS does not need to be involved in driving the lens at all until the lens driving is completed. Further, when a request from the camera is met, the contents of the counter can be sent to the camera.

When an aperture control command is sent from the camera, a known stepping motor DMTR for driving the aperture is driven in accordance with the number of aperture stages sent at the same time. Since the stepping motor can perform open control, it does not require an encoder for monitoring the operation.

ENCZ is an encoder circuit attached to the zoom optical system, and the in-lens control circuit LPRS receives the signal SENCZ from the encoder circuit ENCZ to detect the zoom position. Lens parameters at each zoom position are stored in the in-lens control circuit LPRS, and when a request is received from the microcomputer PRS on the camera side, a parameter corresponding to the current zoom position is sent to the camera.

The ICC is a photometric area sensor for focus detection and exposure control composed of a CCD or the like and its driving circuit. The ICC is selected when the signal CICC is "H",
It is controlled by the microcomputer PRS using I and SCLK.

ΦV, φH, φR are reset signals for reading the output of the area sensor, and a sensor control signal is generated by a drive circuit in the ICC based on the signal from the microcomputer PRS. The sensor output is amplified after reading from the sensor unit, and is input as an output signal IMAGE to an analog input terminal of the microcomputer PRS. The microcomputer PRS converts the signal into an analog signal, and sequentially stores the digital value in a predetermined address on the RAM. Go. Using these digitally converted signals, distance distribution measurement and focus adjustment or photometry of the object scene are performed.

In FIG. 6, the camera and the lens are shown as being separate (lens can be replaced).
The present invention has no problem even if the camera and lens are integrated, and the present invention is not limited to these.

Based on the above configuration, the distance distribution is measured based on the flowchart of FIG.

In step (201), a sensor image is captured. The capture of the sensor image is performed as follows.

First, the sensor is reset. More specifically, the reset operation is performed inside the ICC by setting the control signals φV, φH, and φR to “H” at the same time by the microcomputer PRS for a certain period of time. Next, an accumulation start command is sent from the microcomputer PRS to start accumulation, and later the end of accumulation is detected. Then, the control signals φV and φH are driven to output the sensor output IMAG.
E are sequentially read out, A / D converted by the microcomputer PRS and stored in the RAM, and the capture of the output signal of the sensor in step (201) is completed.

The output signal data of the two sensors is stored in RAM
They are stored in the upper predetermined areas IMG1 and IMG2.

Next, in step (202) and thereafter, "m
Defocus distribution information (defocus map) composed of (× n) blocks (m and n are integers of 1 or more) is created.

In step (202), variables х and す る indicating the coordinates of the block are initialized. In the next step (203), a signal necessary for the distance calculation of the block (х, у) is extracted from the image data IMG1 on the RAM and copied to a predetermined address A on the RAM. In the following step (204), another signal necessary for the distance calculation of the block (х, у) is extracted from IMG2,
It is copied to a predetermined address B on the RAM.

In the next step (205), the address A
A known correlation operation COR (A, B) is performed on the luminance distribution signal stored at the address B and the luminance distribution signal stored at the address B, and a shift amount δ between the two image signals is calculated. In the following step (206),
The calculation of the distance value from the image shift amount δ is performed by a well-known function f (δ), and the distance value or the defocus is stored in a predetermined address D (х, у) secured for the distance distribution recording on the RAM. You. Then, in step (207), the value of х is increased by one, and the processing target is moved to an adjacent block.

In step (208), x is compared with the resolution m of the distance map in the x direction, where "x <
If "m" is determined to be true, the process returns to step (203), and the calculation and storage of the distance value are performed on the adjacent block in the x direction in the same manner as described above. If “x <m” is determined to be false, the process proceeds to step (209), where x is initialized and y is increased by one.

In step (210), the value of y is evaluated, and when it is determined that "y <n" is true, the process returns to step (203) again, and the operation for the next block sequence is started. When it is determined that “y <n” is false, the distance calculation for all blocks is completed, the distance distribution creation subroutine ends, and step (10) in FIG.
1) is completed.

Next, in step (103), the main subject area detection subroutine is called.

The contents of the main subject area detection subroutine performed by the main subject area detection section 52 will be described with reference to FIG.

In step (301) of FIG. 8, numbering is performed for each object (group) constituting the scene.

For example, as shown in FIG. 9, when the division processing is performed while performing raster scanning from the upper left block of the screen as indicated by the arrow in the figure, the block G (x, y) above the target block G (x, y) y-1) and the left lock G (x-1, y)
If it is determined whether or not the block belongs to the same group, it can be determined whether all adjacent blocks are the same block. At this time, the upper side of the screen (y =
0) and the block on the left side (x = 0) do not have the upper block and the left block, respectively, so that no processing is performed on them.

The result of the determination is stored in the memory G on the RAM.
Record in (0,0) to G (m-1, n-1). First,
The block of (x, y) = (0, 0) has a group number g =
Registered as 1, and if a group having a different area is detected, the number of g is increased by one and set as the group number of the block.

By this processing, for example, a photographing scene as shown in FIG. 10A is given a number for each group as shown in FIG. 10B. Since the numbering process itself is a known technique called “labeling method”, a flowchart of the entire area division is omitted.

The method of determining whether each block is the same block is described in detail in Japanese Patent Application No. 08-325327, and will not be described here. When the difference of the distance values is within a predetermined range, a method of processing as the same block is adopted.

Next, in step (302), the number of subjects detected in step (301) is set in a variable Gnum.

After step (303), the characteristics of each group constituting the photographing space are evaluated, and from these characteristics, the group representing the main subject is determined from all the groups.

In step (303), 1 is set to a variable Gcur representing the group to be operated. In the next step (304), the main subject degree S (Gcur) of the subject area of the group number Gcur is calculated. The main subject degree calculates characteristics such as an average distance, an area width, a height, and a position on a screen, and evaluates them comprehensively to determine an area considered as a main subject. For example, as the main subject degree evaluation function S (Gcur), the aforementioned equation (1) can be considered.

In step (305), the value of the variable Gcur is increased by one, and the operation target is moved to the next group. In the next step (306), the values of the variables Gcur and Gnum are compared to check whether or not the operation has been completed for all the groups. As a result, if “Gcur ≦ Gnum”,
Since the operations for all the groups have not been completed, the process returns to step (304), and if "Gcur>Gnum",
Move to step (307).

In step (307), a function MAX for obtaining a group number having the largest value among all the calculated main subject degrees S (1) to S (Gnum) is used to determine a group having the highest main subject degree. The number is assigned to the variable Gmain. The area corresponding to the number represented by Gmain represents the main subject area. Then, in step (308), the sub-routine of main subject area detection is completed, and step (102) in FIG.
Is completed.

In step (103) of FIG. 2, a subroutine for measuring the luminance (distribution) of the subject (field) by the photometric unit 55 is called. As described above, in the present embodiment, the luminance (distribution) of the subject or the object scene is determined using the optical system and the area sensor used in the distance distribution measuring unit 51.
Is measured. By using the area sensor, the luminance distribution of the entire object scene can be obtained finely, and the average luminance of each region including the entire object scene and the main object region obtained in step (102) is obtained. As a result, the average luminance of a plurality of subject areas can be easily obtained.

The contents of the photometry subroutine performed by the photometry unit 55 will be described with reference to FIG.

In step (401) of FIG. 11,
First, the average luminance of the entire object is obtained from the luminance information of the entire object field. Actually, the sensor image used in the distance distribution measurement subroutine of step (101) in FIG. 2 is treated as a luminance output, and the average value of all the images is calculated.

Next, in step (402), the number of subject areas detected in step (102) in FIG.
Set to num. Then, after step (403),
The average brightness of each group area constituting the shooting space is calculated.

In step (403), 1 is set to a variable Gcur representing a group to be measured. In the next step (404), the average luminance of each subject area of the group number Gcur is calculated. In the following step (405), G
Increment the value of cur by one and move the photometry calculation target to the next group. Then, in step (406), the values of Gcur and Gnum are compared, and it is checked whether the photometric calculation has been completed for all groups. As a result, "Gcur
If .ltoreq.Gnum, the calculation for all groups has not been completed, so the flow returns to step (404), and "Gcur
If> Gnum ", the process proceeds to step (407), the photometry subroutine is terminated, and step (103) in FIG. 2 is completed.

Next, the depth of field determination subroutine of step (104) in FIG. 2 is executed.

Here, the depth of field such that all the currently set and selected main subject areas are in focus,
Specifically, the required aperture value of the photographing optical system is obtained.

The contents of the depth of field determination subroutine performed by the depth of field determination unit 57 will be described with reference to FIG.

In step (501) of FIG. 12A, first, a defocus amount Dn closest to the camera side in a subject area to be focused is obtained. Here, when one area is selected as a subject, the defocus amount is closest to the camera side in that area, and when a plurality of objects are selected, the defocus amount is closest to the camera side in all selected areas. Becomes a defocus amount close to.

In the present embodiment, the initial value of the number of selected regions is set to 1 (actually, only the main subject is selected, and depth-of-field priority shooting is not performed). The number is increased (that is, the depth of field priority is automatically set).

In the next step (502), the defocus amount Df which is the farthest from the camera in the subject area to be focused is determined. Also in this case, when one area is selected as the subject, the defocus amount is the furthest to the camera side in that area, and when a plurality of subjects are selected, the defocus amount is the most defocus amount in all the selected areas. Defocus amount far away from the camera.

In the following step (503), the following equation is calculated.

F = (Df−Dn) · A / Δ Here, A is a coefficient as shown in FIG. 12 (b), and an object having both ends of a subject n near and a subject f far from the camera. This is for calculating the defocus amount for the point (c) that internally divides the depth of field into α and β. This internal division ratio can be set freely according to the shooting mode or the like. This defocus amount is the size of the smallest circle of confusion Δ (35 μm).
And the required aperture value F is obtained.

Then, the process proceeds to step (504), where the subroutine for determining the depth of field is completed, and step (104) in FIG. 2 is completed.

In step (105) of FIG. 2, the focus adjustment distance determination section 54 determines the distance to be adjusted.

In the present embodiment, the previous step (10
The target point which internally divides the depth of field determined in 4) (Fig. 1
In order to adjust the focus with respect to point (c) of 2 (b), the defocus amount to be adjusted in step (104) is actually obtained. Therefore, here, the calculation of the drive amount for driving the focus adjusting lens of the photographing optical system is performed.

In step (106) of FIG. 2, a subroutine for determining a shutter speed in the photographing exposure operation is executed. This is determined from the photometric result obtained in step (103) and the aperture value and film sensitivity obtained in step (104), and is the average of all the subject areas selected from the photometric result, that is, the average value of each area. , And is derived from the following relational expression of the APEX method.

TV + AV = BV + SV Here, TV is an exposure time (shutter speed), AV is an aperture value, BV is luminance, and SV is a corresponding value of film sensitivity.

The contents of the shutter speed determination subroutine performed by the shutter speed determination unit 56 will be described with reference to FIG.

In step (601) of FIG. 13, first, the total number of selected areas and the total luminance information of the selected areas are initialized (= 0). In the next step (602), the number of subject areas detected in step (102) of FIG. 2 is set in a variable Gnum. The next step (603)
Then, the variable Gcur representing the target group of the luminance information is set to 1
Set. Then, in step (604), it is determined whether the current target group is the selected area.
If the area is selected, step (605)
If it is a non-selection area, the process proceeds to step (607).

In step (605), the value of the variable Gsum indicating the current number of selected areas is increased by one. In the next step (606), the luminance information Bcur of the current target area is added to the variable Bsum indicating the total luminance information of the selected area. In the following step (607), the value of Gcur is increased by one, and the operation target is moved to the next group. Then, in step (608), the values of Gcur and Gnum are compared to check whether or not the photometric calculation has been completed for all the groups. As a result, if “Gcur ≦ Gnum”, the calculation for all the groups has not been completed, so the flow returns to step (604). If “Gcur> Gnum”, the flow proceeds to step (609), where the total luminance of the selected area is calculated. The average luminance information is obtained by dividing the information by the number of selected areas.

Then, in step (611), the aforementioned A
The PEX calculation is performed to determine the shutter speed. Then, the process proceeds to step (612), where the subroutine for determining the shutter speed is ended, and step (106) in FIG. 2 is completed.

Step (10) in FIG.
After the operations in the microcomputer PRS of 1) to (106),
In step (107), the microcomputer PRS performs the operation shown in FIG. 6 so that the target point determined in the previous step (105) is focused.
Is sent to the lens LNS, and the in-lens control circuit LPRS controls the motor LMTR to complete the current focus adjustment.

In the next step (108), it is determined whether there is any difference in the current number of subject areas, that is, the number of selected main subject areas. In the present embodiment, a switch SW that responds to the operation of a rotation operation member that is the main subject region number changing member 53 or a release button that starts shooting.
By the state detection of 2, it is checked whether the photographer wants to change the set number. That is, if the rotation operation member, which is the main subject area number changing member 53, is operated before the switch SW2 is pressed, the photographer wants to change the number of subject areas, and the switch SW2 is pressed as it is. If so, it is determined that you are satisfied with the current settings.

First, the description will be continued assuming that no change is made. In the following step (110), the microcomputer P
MG1, MG2 for starting the first and second curtain of shutter from RS
Signals SMG1 and SMG2 correspond to step (10
Occurs at time intervals at the shutter speed determined in 6),
The exposure operation is performed and the photographing is completed.

On the other hand, if it is requested in step (108) to change the setting of the number of selected subject areas, the process proceeds to step (10).
In 9), a subroutine for selecting the number of subject areas is called. The operation of this subroutine will be described with reference to FIG.

As described above, when the change of the main subject area is requested in step (108), that is, when the rotation operation member is operated, the rotation direction is detected in step (701). In the present embodiment, a system for inputting a right rotation to increase or a left rotation to decrease from the currently set number of selected areas with a uniaxial rotary operation member (not shown) (not shown) when increasing the number of selected areas. According to the above detection result, the process proceeds to step (702) if it is leftward, and to step (704) if it is rightward. In step (702) and step (704),
According to the rotation direction detected in step (701), it is determined whether the number of subject areas can be changed from the currently set value.

That is, in step (702), since the number of selected areas is reduced, it is determined whether or not the number of selected areas is one in order to avoid an error that the number of selected areas becomes zero. On the other hand, in step (704), since the number of selected areas is increased, it is determined whether or not the number is the maximum value in order to avoid an error exceeding the maximum number of areas in the scene. Step (702),
If both (704) do not enter the error state, the process proceeds to steps (703) and (705), respectively, to increase or decrease the number of selected areas. Conversely, if an error occurs, the change input is ignored and the subroutine ends.

In step (706), the selection area is set according to the changed number of selected areas. More specifically, when increasing, a non-selected area in which the main subject degree evaluation function S (Gcur) obtained by the above equation (1) is high is added to the selected area. )), The area where the main subject degree evaluation function S (Gcur) is low is deleted.

Area selection corresponding to the number of selected areas changed as described above is performed, and the process proceeds to step (707), where the subject area number selection subroutine is terminated, and step (109) in FIG. 2 is completed.

When the subroutine for selecting the number of subject areas in step (109) is performed as described above, the process returns to step (104) to determine the necessary depth of field from the current subject selection area, and then proceeds to step (105). , (106) determine the focus adjustment distance and the shutter speed.
The lens is driven in 7), and it is detected again in step (108) whether the operation is a change operation or a photographing operation.

If a series of operations for changing the main subject area from step (108) will be described with reference to the photographing scene of FIG. 10A, first, the subject having only the group number 3 in FIG. When an area is selected, FIG.
If the right rotation of the dial is detected in step (701), the group number 4 shown in the figure is added as a new selected subject area, and the depth of field including this area, focus adjustment, If the shutter speed is set and the clockwise rotation of the dial is detected again in step (701), the subject area of group number 6 in the figure is additionally selected and set as a newly selected subject area. Become. The photographer can perform the intended photographing by pushing the switch SW2 until the switch SW2 is turned on at the time when all the subjects intended by the photographer are in focus.

In the first embodiment described above, for example, distance information or defocus information closest to the camera side is obtained from the main subject area detected from the distance distribution information (the information obtained here is: As is clear from FIG. 10B, a plurality of pieces of information corresponding to a large number of ranging points are obtained instead of one piece of information for each of the front and the back as in the related art.) Depth-of-field priority shooting is automatically performed, so that a beginner cannot easily perform depth-of-field priority shooting like a conventional camera having only one focus detection area. As with conventional cameras with multiple focus detection areas, there is no focus detection area at the subject position, so the depth becomes unnecessarily deep, or the exposure time becomes longer, causing camera shake. Problems such as Can.

Further, the photographer can change the automatically set number of subject areas to an arbitrary number by using a predetermined (rotational) operation member. This has the advantage that depth of field priority shooting can be performed more easily.

Although one rotary operation member is assumed as the input means, the present invention is not limited to this. For example, two input switches or slide levers may be used.

(Second Embodiment) In the description of the first embodiment described above, the number of selected subject areas is initially set to one, and the number of selections is increased as necessary, so that the subject is automatically picked up. The description has been made with an example of a system in which depth-of-field priority shooting is performed. However, so-called shooting modes (portrait,
If the initial value is changed and set according to the scenery, etc., more responsive shooting can be performed.

FIG. 15 shows an overall processing flow in the second embodiment. The only difference from the first embodiment (FIG. 2) is the step (804), that is, the addition of a selection area number setting subroutine corresponding to the shooting mode.

The subroutine for setting the number of selected areas will be described with reference to FIG.

In this subroutine, first, step (9)
At 01), it is determined whether the current mode is the landscape photography mode. Similarly, in step (903), it is determined whether the mode is the sports shooting mode. In other than these two modes, the initial number of areas is set to "1" in step (905) as a basic setting value, while in the scenery and sports modes, the initial number of areas is set in steps (902) and (904), respectively. 2 ".

Here, the initial setting values are changed only in both the landscape and sports modes. However, the initial setting values may be individually and finely set in each mode, and the initial setting values themselves may be variable.

According to the second embodiment described above, the initial value to be automatically set can be changed depending on the shooting mode. Therefore, it is possible to realize a camera capable of adjusting the focus and setting the depth of field in accordance with the state of various subjects in photographing and the situation on the photographing side.

(Modification) In the above embodiment,
Although the main subject area is detected from the distance distribution information, the present invention is not limited to this, and a configuration in which the main subject area is detected based on the defocus distribution information may be employed.

In the above embodiment, an example in which the number of main subject regions can be increased or decreased by an external operation is assumed, so that an example in which the present invention is applied to a TTL single-lens frame camera is shown. Application to video cameras, electronic still cameras, and the like is also possible. However, in the case of this type of camera, the number of main subject areas cannot be changed by the photographer's will, but other effects can be exhibited.
Further, the present invention can be applied to an optical device other than the camera, which has both functions of focus adjustment and depth adjustment.

[0121]

As described above, according to the present invention,
It is possible to provide an optical device that does not require a troublesome operation of focusing on a main object a plurality of times and prevents the depth from becoming deeper than necessary.

Further, according to the present invention, it is possible to provide an optical device capable of changing the number of main target areas automatically set to the number of areas reflecting the intention of the photographer as necessary. is there.

According to the present invention, when performing depth-of-field priority photographing, it is not necessary to perform a troublesome operation of focusing on the main subject a plurality of times.
An object of the present invention is to provide a camera capable of preventing an unnecessary deep depth and a long exposure time.

The number of main subject areas automatically set is changed, if necessary, to the number of areas reflecting the intention of the photographer, and the depth of field priority photographing reflecting the intention of the photographer is changed. A camera capable of performing the following.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a camera according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a schematic operation of the camera according to the first embodiment of the present invention.

FIG. 3 is a diagram schematically illustrating an arrangement of an optical system of the camera according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing an arrangement of an optical system of the camera according to the first embodiment of the present invention.

5 is a diagram of the optical system of FIG. 4 as viewed from above.

FIG. 6 is a block diagram showing an internal configuration of the camera according to the first embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of distance distribution measurement in step (101) of FIG. 2;

FIG. 8 is a flowchart showing an operation of detecting a main subject area in step (102) of FIG. 2;

FIG. 9 is a diagram for explaining a method of actually dividing an area in the operation of FIG. 8;

FIG. 10 is a diagram showing an example of a result of labeling in the operation of FIG. 8;

FIG. 11 is a flowchart showing a photometric operation in step (103) of FIG. 2;

FIG. 12 is a flowchart showing the operation of determining the depth of field in step (104) of FIG. 2 and a diagram for assisting the description of the operation.

FIG. 13 is a flowchart showing an operation of determining a shutter speed in step (106) of FIG. 2;

FIG. 14 is a flowchart showing an operation of selecting a subject area in step (109) of FIG. 2;

FIG. 15 is a flowchart illustrating a schematic operation of the camera according to the second embodiment of the present invention.

FIG. 16 is a flowchart showing an operation of setting the number of selected areas in step (804) of FIG.

FIG. 17 is a diagram illustrating a certain shooting scene, its distance distribution measurement result, and a state in which groups are grouped for each region characteristic from the distance distribution measurement result.

[Explanation of symbols]

 Reference Signs List 51 distance distribution measuring section 52 main subject area detecting section 53 main subject area changing member 54 focusing distance determining section 55 photometric section 56 shutter speed determining section 57 depth of field determining section 58 lens driving device PRS microcomputer LPRS in-lens control circuit LNS Lens ICC Focus detection and photometry sensor and drive circuit

Claims (8)

[Claims] 1. A distribution information measuring means for measuring a two-dimensional distribution of a distance or a defocus amount in a screen, and dividing the screen into a plurality of target areas based on the distribution information; A region detecting unit that detects at least one region; and an adjusting unit that adjusts a focal position and an aperture of an optical system so that the entire detected main target region is in focus. Optical device. 2. The area detecting means detects at least one or more main target areas from a plurality of target areas in order, and performs an external operation on the number of the automatically detected main target areas. 2. The optical device according to claim 1, further comprising an operation member for changing the number of main target areas by the operation member. 3. The optical device according to claim 1, wherein the number of main target areas detected by the area detection unit is set in advance. 4. A distribution information measuring means for measuring a two-dimensional distribution of a distance or a defocus amount in a screen, dividing the screen into a plurality of subject areas based on the distribution information, and dividing a main subject from the plurality of subject areas. An area detecting means for detecting at least one area, and an adjusting means for adjusting a focus position and an aperture of an optical system such that the entire area of the detected main subject area is in focus. Camera. 5. The area detecting means detects at least one main subject area from a plurality of subject areas. The number of the main subject areas automatically detected is determined by an external operation. The camera according to claim 4, further comprising an operation member for changing the number of subject areas. 6. The camera according to claim 4, wherein the number of main subject areas detected by said area detection means is set in advance. 7. The camera according to claim 4, wherein the number of main subject areas detected by said area detecting means is set according to a photographing mode. 8. The camera according to claim 5, wherein the camera has a structure in which a focus state of each area can be observed through a screen.