JPH11337814A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the information gain time for focusing by performing the ranging or the measurement of two-dimensional distribution of a defocus amount for a limited area and performing a follow up operation. SOLUTION: When a moving body photographing mode is set, and if present focus detective operation isn't the first, an area to be made as a detective object is set. For instance, in the whole focus detective area A of all 35 points constituted of vertically five divisions and, horizontally seven divisions, a main objective area B is decided by the last focus detective operation. Then, in the setting state of the present focus detective operation objective area, the area C in the vertical direction, the area D in the horizontal direction are set. As the number of the areas, it is narrowed to the number of 1/3 or below of the whole area. For instance, when the present main objective area becomes the area E, similarly, the next focus detective area operation area is set in the areas F, G. The distance distribution of a field to be photographed is measured for the set focus detective area. In such a manner, the ranging or the measurement of two-dimensional distribution of the defocus amount is performed only for the prescribed area and the follow-up operation is performed based on obtained information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device having an automatic focusing function, such as an autofocus camera or a surveillance camera.

[0002]

2. Description of the Related Art A focus detection function represented by a camera or the like has advanced from a single detection area at the center to three and five points, and the detection range has been surely expanded over an imaging area. This includes not only advances in detection optics, but also sensors,
In addition, advances in microcomputers and the like that control the control are essential.

[0003] The multi-point detection area is a state in which, in ordinary photographing, the background is focused on instead of the subject,
It is very effective in preventing so-called "voids". Further, when photographing a moving subject, it is possible to reduce the possibility that the focus detection area is removed from the subject.

[0004] FIG. 14A is a diagram in which a one-dimensional one-point range narrow as shown in FIG. On the other hand, FIG. 14B shows an example in which the focus detection area is enlarged, and the detection area B is three areas with respect to the shooting screen A. This is obtained by increasing three detection areas in the direction orthogonal to the detection area in FIG.

Since the focus detection area is increased from one point at the center to three points, it is not necessary to always focus on the object at the center, and the degree of freedom in photographing is improved.

If this is further developed, FIG.
As described above, the area AF has a two-dimensional area having a detection area B with respect to the photographing screen A (actually, many focus detection areas are gathered to some extent densely).

[0007]

The area AF, in which a large number of focus detection areas of the camera are gathered, has the merit that the photographer can concentrate on the original photographing without any missing or falling off as in the prior art, but has the merit that the photographer can concentrate on the original photographing. If the focus detection calculation is performed on the focus detection point, it may take too much time, so that a so-called shutter chance may be missed.

In particular, when the subject is moving, the influence is great, and how to shorten the calculation time is a major problem.

(Object of the Invention) It is an object of the present invention to efficiently limit a target region used for focusing to a necessary and sufficient region, and to shorten the time for obtaining information used for focusing. It is intended to provide a device.

[0010]

In order to achieve the above object, the present invention provides an optical apparatus having a measuring means for measuring a two-dimensional distribution of a distance measurement or a defocus amount in a plurality of regions in an observation screen. When performing a tracking operation that continues to focus on a moving object, the target region used for focusing is limited to a predetermined region centered on the focusing region in the previous tracking operation from the plurality of regions. An optical device having a focus adjusting unit that causes the measuring unit to measure the distance or measure the two-dimensional distribution of the defocus amount only in the predetermined area, and performs the following operation based on obtained information. Things.

In the above configuration, when a tracking operation is performed to keep the moving object in focus, the target area used for focusing is, for example, centered on the focusing area in the previous tracking operation. It is limited to an area that can be regarded as a predetermined cross or an area in one predetermined direction centering on the in-focus area in the previous following operation, and two-dimensional distance measurement or defocus amount only in these areas. The distribution information is measured, and the focus is kept on the moving object based on the obtained information.

[0012]

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

A method for limiting and selecting a focus detection area for capturing a moving object will be described by taking an automatic focusing camera capable of detecting a focus in a two-dimensional area as an example.

FIG. 1 is a block diagram of basic components of a camera according to an embodiment of the present invention.
1 is a distance distribution measuring circuit for measuring the distance of an arbitrary place in the scene, 52 is a main subject area detecting circuit for detecting an area where a main subject is present in a shooting screen, and 53 is the main subject area detecting circuit 52 A selection area setting circuit for setting the current focus detection area range in accordance with the previous main subject area automatically determined in step, a focus adjustment distance determining circuit for a photographing optical system in accordance with information on the determined main subject area, An optical system 56 is a lens driving device that drives a lens to adjust the focus. The control device 57 is actually embodied by a CPU, a RAM and a ROM of a microcomputer. Among them, the distance distribution measuring circuit 51 is embodied by a microcomputer and a measuring optical system, and thus is expressed over a dotted line.

FIGS. 2 to 5 are diagrams showing specific examples of the configuration of the camera shown in FIG.

FIG. 2 is an arrangement diagram of optical components of a camera for detecting the distance of the field. In FIG. 2, 1 is a photographing lens, 8 is a field lens, 9 is 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. 3 shows a layout when the detection optical system shown in FIG. 2 is suitable for a camera. In FIG. 3, reference numeral 6 denotes a quick return mirror, 18 denotes a pentaprism, and 19 denotes a pentaprism.
Is a split prism, 20 is a reflection mirror, and the other is the same as FIG. FIG. 4 is a view of the layout of FIG. 3 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. 5 is a block diagram showing a configuration of a camera provided with each component as shown in FIG. 2, and the configuration will be described first.

In FIG. 5, PRS is the control unit 5 of FIG.
7. A camera control device corresponding to, for example, a CP
It is a one-chip microcomputer having a U (central processing unit), a ROM, a RAM, and an A / D conversion function. The control device (hereinafter referred to as a microcomputer) PRS of this camera is R
In accordance with a camera sequence program stored in the OM, a series of camera operations such as an automatic exposure control function, an automatic focus adjustment function, and film winding / rewinding are performed. Therefore, the microcomputer PRS uses the communication signals SO, S
I, SCLK, communication selection signals CKCM, CDDR, CI
Using the CC, 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, described as “H”, and a low potential level is described 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 transmits each of SCLK and SO via 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. OLC is an external liquid crystal display device located above the camera, and ILC is a viewfinder 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, MG2 are magnets for starting the movement of the first and second curtains of the shutter, and are energized by signals SMG1, SMG2 and amplification transistors TR1, 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 simultaneously transmitted drive amount and direction. , 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.

Therefore, 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 driving of the lens 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 well-known stepping motor DMTR for driving an aperture is driven in accordance with the number of aperture stages sent simultaneously. 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.

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

ΦV, φH, and φR are readout and reset signals of the area sensor output, 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. 5, 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.

Next, a series of operations by the microcomputer PRS will be described.

FIG. 6 is a flowchart showing the flow of the entire processing, and the description will be made in accordance with the flowchart.

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

In step (101), first, it is determined whether the current automatic focus adjustment mode is set to the moving object photographing mode. If the moving object shooting mode has not been set, the process directly proceeds to step (102), and the current focus detection calculation target area is set to the entire focus detection area.
On the other hand, if the moving object shooting mode is set, the process proceeds to step (103), and it is determined whether or not the current focus detection operation is the first in the moving object shooting mode. This is because if it is the first time, where the main subject exists has not yet been clearly detected, it is necessary to first detect the entire focus detection area. Therefore, the step (103)
If it is determined that the current focus detection operation is the first in step (102), the same as in the non-moving object shooting mode,
Then, the current focus detection calculation target area is set to the entire focus detection area.

If the current focus detection operation is not the first, the process proceeds from step (103) to step (104) to call a selection area setting subroutine for setting an area to be detected. An outline of the selection area setting subroutine will be described with reference to FIG. Note that this selection area setting is performed by a portion in the microcomputer PRS corresponding to the selection area setting circuit 53 shown in FIG.

In FIG. 7A, A represents the entirety of the focus detection area of 35 points composed of 5 vertical divisions and 7 horizontal divisions. B is an area determined to be the main subject area in the previous focus detection operation. That is, the focus adjustment operation was performed last time based on the focus detection result of the area B.

FIG. 7B shows the setting state of the current focus detection calculation target area. The area C is set in the vertical direction and the area D is set in the horizontal direction. This is a selection of an area that can be regarded as a cross centering on the area B in FIG. 7A, which is the previous main subject area. The number of areas is “11”,
That is, the number is reduced to 1/3 or less of the entire area. This is because the photographer follows framing with respect to the same subject, and the area to be considered as the next main subject area is a cross area centered on the previous main subject area, which is necessary and sufficient. is there.

For example, the current main subject area is shown in FIG.
In the case of the area E shown in FIG. 7, similarly, the next focus detection calculation target area is set in the areas F and G shown in FIG.
Becomes

The above is performed in step (104).
This is the contents of a selection area setting subroutine for setting an area to be detected.

In the following step (105), a subroutine for measuring the distance distribution of the object scene is called for the focus detection area set as described above. This distance distribution measurement will be described with reference to the flowchart of FIG. The measurement of the distance distribution is performed by the microcomputer PRS.
The part corresponding to the distance distribution measuring circuit 51 shown in 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, "mx
The distance distribution information (distance map) composed of “n” blocks (m and n are positive numbers equal to or greater than 1) is created.

In step (202), variables х and у indicating the coordinates of the block are initialized, and in the next step (203), a signal necessary for the distance calculation of the block (х, у) is stored in the RAM. Is extracted from the image data IMG1 and copied to a predetermined address A on the RAM.
In the following step (204), the block (х,
у), the other signal necessary for the distance calculation
It is extracted from MG2 and copied to a predetermined address B on the RAM.

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

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

In the following 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 to start the operation for the next block sequence. When it is determined that “y <n” is false, the distance calculation for all the blocks is completed, and the distance distribution creating subroutine (the operation in step (101) in FIG. 6) ends.

When the detection target area is set to a cross area, the initial values of x and y and the resolutions m and n change for each position. These are stored as a function relating to the location of the previous main subject area or as a numerical table and individually referred to.

Next, in step (106) of FIG. 6, a main subject area detection subroutine is called. Here, first, the contents of the main subject area detection subroutine in the case where the detection target area is the entire area will be described with reference to the flowchart of FIG. The main subject area detection is performed by a portion of the microcomputer PRS corresponding to the main subject area detection circuit 52 shown in FIG.

Returning to FIG. 6, in step (106), a subroutine for detecting a main subject area is called. FIG. 9 shows the contents of the main subject area detection subroutine.
This will be described according to the flowchart of FIG. Note that the detection of the main subject region is performed by a portion corresponding to the main subject region detection circuit 52 in FIG. 1 in the microcomputer PRS.

In step (301) of FIG. 9, numbering is performed for each object (group) constituting the scene.
For example, as shown in FIG. 10, when performing division processing while performing raster scanning from the upper left block of the screen as indicated by the arrow in the figure, the block G above the block of interest G (x, y)
If it is determined whether (x, y−1) and the left block G (x−1, y) are in the same group, as a result, it is determined whether all adjacent blocks are the same block. It can be carried out. At this time, the blocks on the upper side (y = 0) and the left side (x = 0) of the screen do not have the upper block and the left block, respectively, so that no processing is performed on them. Also, 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) is registered as a group number “g = 1”, and if a group having a different area is detected, the number of g is increased by one to increase the block number. Group number. By this processing, for example, a shooting scene as shown in FIG. 11A is given a number for each group as shown in FIG. 11B. Since the numbering process itself is a known technique called “labeling method”, a flowchart of the entire area division is omitted.

The method of judging whether each block is the same or not is described in detail in Japanese Patent Application No. 8-325327 disclosed by the present applicant, and a description thereof will be omitted.

Next, in step (302), the number of subjects detected in step (301) is determined by a variable G.
Set to num. After step (303),
The characteristics of each group constituting the shooting space are evaluated, and a group representing the main subject is determined from all the groups based on the characteristics.

In step (303), 1 is set to a variable Gcur representing the group to be operated. In the next step (304), it is determined whether or not the moving object shooting mode is set as the current automatic focus adjustment mode. If the moving object shooting mode is set, the process proceeds to step (305), and the object image plane speed is set. The characteristics required for the evaluation in tracking the moving object, such as the amount of change and the rate of change, are calculated. Since the amount and rate of change of the object image plane speed are disclosed in Japanese Patent Application No. 62-32823 or Japanese Patent Application No. 1-27206, detailed description will be omitted. Then, the process proceeds to step (306).

If the moving object photographing mode is not set, the process directly proceeds to step (306), where the main subject degree S (Gcur) of the subject area of the group number Gcur is set.
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, the following expression can be considered as the main subject degree evaluation function S (Gcur).

S (Gcur) = W ₁ × (width) × (height) + W
₂ / (distance from screen center) + W ₃ / (average distance) In the above equation, 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.

On the other hand, in the case of capturing a moving object, the above-mentioned function uses an evaluation function that also takes into account the amount and rate of change of the image plane speed of the subject.

In the next step (307), Gcu
Increase the value of r by one and move the operation target to the next group.
In the following step (308), the values of Gcur and Gnum are compared to check whether the operation has been completed for all groups. As a result, if “Gcur ≦ Gnum”, the operations for all the groups have not been completed, so the flow returns to step (304) and the same operation is performed.

On the other hand, if "Gcur>Gnum", the process proceeds to step (309), where the group number having the largest value among all the calculated main subject degrees S (1) to S (Gnum) is obtained. The number of the group having the highest degree of main subject is assigned to the variable Gmain by the function MAX. Gmain
The area corresponding to the number represented by represents the main subject area.
Then, in the next step (310), the main subject area detection subroutine (the operation of step (106) in FIG. 6) ends.

In the subsequent step (107) of FIG. 6, a subroutine for determining the distance to be adjusted is called. Here, a subroutine for determining a distance to be focused from the current main subject area is executed. This will be described with reference to the flowchart of FIG. The detection of the focus adjustment distance is performed by a portion of the microcomputer PRS corresponding to the focus adjustment distance detection circuit 54 shown in FIG.

In step (401), a target area in the field is set according to the group number set as the main subject area. First, an area is set according to the result of the main subject area detection subroutine. In the next step (402), it is determined whether the current automatic focus adjustment mode is set to the moving object photographing mode. If the moving object shooting mode is not set, the process proceeds to step (403), and distance information for focus adjustment is calculated from information in the previously set area. Here, since the algorithm which gives priority to the closest object in the same subject area is adopted, the closest distance in the area is obtained.

On the other hand, if the moving object photographing mode has been set, the flow advances to step (404) to perform a moving object tracking calculation required for the moving object photographing mode. This is to obtain an adjustment amount obtained by adding a drive amount for correcting a delay due to a shooting operation such as a release time lag to a focus adjustment amount for the main subject area. This is also Japanese Patent Application No. 62-32823 or Japanese Patent Application No. 1-2.
The detailed description is omitted since it is published in No. 7206.

In the next step (405), the closest distance or the moving object follow-up adjustment distance is set as the final focus adjustment distance, and the focus adjustment distance determination subroutine ends.

In step (108) of FIG. 6, the microcomputer PRS sends a focus adjustment command to the lens LNS having the lens driving device 56 of FIG. 1, whereby the in-lens control circuit LPRS controls the motor LMTR. Control the focus adjustment at the current time (step (10) in FIG. 6).
The operation 7) is completed.

Thereafter, the above operations are repeated to perform a focus adjustment operation on a still or moving subject.

In the above example, as described with reference to FIG. 7, an area that can be regarded as a cross centered on the previous main subject area is set as the current selection target area. Several other shapes are conceivable for this set area. These are shown in FIG.
This will be described with reference to FIG.

FIG. 13A shows a case where the area is set to be more limited when the normal camera is placed in the horizontal position, that is, the in-focus area in the previous follow-up operation (main focus in the previous focus detection operation). This is an example of a predetermined one-way area (a gray area H limited to only the horizontal direction in terms of shooting at a horizontal position) with the blackened area B determined as the subject area as the center. . In the figure, as in FIG. 3, A represents the entirety of the focus detection area of 35 points composed of 5 vertical divisions and 7 horizontal divisions. This is sufficient for panning shots.

FIG. 13B is a view showing the state of FIG.
This is an area setting based on the same idea as (a). FIG.
In FIG. 3C, the target area is a small cross area with a slightly smaller area than the cross area. This is considered sufficient if the subject can be tracked sufficiently. Conversely, FIG.
In (d), the center portion is set to be more substantial with respect to the cross region. That is, all the areas adjacent to the blackened area determined as the main subject area in the previous focus detection operation are added to FIG. 7B.
This is effective for a subject that is slightly difficult to follow.

In addition, as shown in FIGS. 13 (e) and 13 (f), the present invention is also effective in, for example, setting an area such that the entire target area can be sufficiently obtained while reducing every other area.

According to each of the above embodiments, when performing a moving object tracking operation that keeps focusing on a moving object, the focus detection target area is shifted from a plurality of object areas to the focusing area in the previous tracking operation. The focus detection operation is performed only on these areas, and the subject tracking operation is performed. As a result, it is possible to sufficiently reduce calculations and the like necessary for following the subject, and it is possible to bring out the effectiveness of expanding the focus detection area.

In addition to the simple cross, various area settings based on the shape of the cross depending on the photographer, the subject, the photographing conditions, and the like are also effective.

(Modification) In the above embodiment, an example in which the optical apparatus is applied to a single-lens reflex camera is described. However, the present invention is not limited to this. In addition, the present invention can be applied to an optical device having a distance measurement or focus detection area and having a function of performing focusing by using information obtained in these areas.

[0084]

As described above, according to the present invention,
An object of the present invention is to provide an optical device capable of efficiently limiting a target region used for focusing to a necessary and sufficient region and shortening a time for obtaining information used for focusing.

[Brief description of the drawings]

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

FIG. 2 is an arrangement diagram of an optical system of the camera according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing an arrangement of an optical system of the camera according to the first embodiment of the present invention.

FIG. 4 is a view of the optical system of FIG. 3 as viewed from above.

FIG. 5 is a block diagram showing an internal configuration of the camera according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing a series of operations of the camera according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a focus detection target area according to the first embodiment of the present invention.

FIG. 8 is a flowchart showing a distance distribution measuring operation according to the first embodiment of the present invention.

FIG. 9 is a flowchart showing a main subject area detection operation according to the first embodiment of the present invention.

FIG. 10 is an explanatory diagram of an area dividing method according to the first embodiment of the present invention.

FIG. 11 is an example of a result of labeling in the first embodiment of the present invention.

FIG. 12 is a flowchart illustrating a focus adjustment distance determination operation according to the first embodiment of the present invention.

FIG. 13 is a diagram illustrating a focus detection target area according to a second embodiment of the present invention.

FIG. 14 is a diagram illustrating a conventional focus detection target area.

[Explanation of symbols]

 Reference Signs List 51 distance distribution measurement circuit 52 main subject area detection circuit 53 selection area setting circuit 54 focus detection distance determination circuit 56 lens drive circuit 57 control circuit PRS microcomputer LPRS in-lens control circuit LNS lens ICC focus detection and photometry sensor and drive circuit

Claims (9)

[Claims] 1. An optical apparatus having measuring means for measuring a two-dimensional distribution of a distance measurement or a defocus amount in a plurality of regions in an observation screen, performs a tracking operation for keeping a moving object in focus. In this case, the target area used for focusing is limited from the plurality of areas to a predetermined area centered on the in-focus area in the previous tracking operation, and distance measurement or defocus amount is determined only for the predetermined area. An optical apparatus, comprising: a focus adjustment unit that causes the measurement unit to measure a two-dimensional distribution and performs the following operation based on obtained information. 2. The optical device according to claim 1, wherein the predetermined area is an area that can be regarded as a predetermined cross centered on a focus area in a previous following operation. 3. The apparatus according to claim 1, wherein the predetermined area is at least one other area that can be regarded as a predetermined cross centered on the in-focus area in the previous following operation. Optical device. 4. The optical device according to claim 1, wherein the predetermined area is a predetermined one-way area centered on a focus area in a previous tracking operation. 5. The apparatus according to claim 1, wherein the predetermined area is an area at least every other area in a predetermined direction centered on an in-focus area in a previous following operation. Optical device. 6. The apparatus according to claim 1, wherein the predetermined area is an area which can be regarded as a predetermined cross including the in-focus area in the previous following operation and all areas adjacent thereto. Optical device. 7. The predetermined area is an in-focus area in a previous following operation, a partial area adjacent thereto, and at least one other area that can be regarded as a predetermined cross. The optical device according to claim 1, wherein: 8. When the area to be used for focusing is first selected, the area to be used for focusing is determined based on information from all the areas obtained by the measuring means. Claims 2, 3, 4, 5, 6
Or the optical device according to 7. 9. The optical device according to claim 1, wherein the area is a ranging area or a focus detection area.