JP3486464B2 - Automatic focusing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a method for focusing on a selected area.
The lens driving operation is repeatedly performed based on the point detection result,
After a predetermined time based on the results of past multiple focus adjustments
Predict the image plane position and perform focus adjustment after a predetermined time.
Make sure that the image plane position of the elephant matches the image plane position of the lens.
Focus adjustment with predictive control means to perform lens drive
DressPlace ofIt is about improvement. [0002] 2. Description of the Related Art Conventionally, an image plane position caused by a movement of a subject is known.
The focus adjustment tracking delay caused by changes in
Therefore, the change in the image plane position is detected,
There is disclosed an apparatus for performing focus adjustment with tracking correction.
You. In the above-mentioned conventional apparatus, a plurality of positions in a screen are
(Focus detection area)
When performing predictive control (follow-up correction) for a moving subject,
Uses data from the focus detection area with high continuity of image plane position change.
By switching the focus detection area as
Always focus on the main subject even if the subject moves in the plane
Detection can be performed and predictive control can be continued continuously
Is to do so. [0004] SUMMARY OF THE INVENTION
In the past case, when the subject went away,
Problems may occur. FIG. 15 shows five focus detection areas in the screen.
Viewfinder when shooting with a camera
The focus detection areas A to E are respectively
Focus detection is performed for different subjects, and the main
The focus detection area for the body is the C focus detection area.
A. In such a state, the main subject is moving away.
In this case, the image plane movement of each focus detection area is as shown in FIG.
become. At this time, the main subject is focused on C at time T1.
When it is recognized as being in the point detection area and predictive control is performed,
High continuity of data in the focus detection area of C until point detection
Therefore, data C1 to C6 are used for predictive control. However, as for the data at time T7,
Straight line connecting C6 and C7 to the straight line connecting C5 and C6
The slope of the straight line connecting C6 and A7 is closer than that of
Is high. Therefore, at time T7, the focus detection area
Switch the area from C to A, and use the data in A7 to predict
The main subject is moving as indicated by the broken line.
I judge that. Then, at time T8, C6 and A
Data with high continuity to the straight line connecting 7 is judged to be E8
Then, the focus detection area is changed to E. Similarly, time
T9 uses the data of B9, and T10 uses the data of D10.
Data will be used. Thus, a camera having a plurality of focus detection areas
In the camera, the focus detection area is used only for the continuity of the image plane movement.
When switching the range, incorrect switching as described above
I went there. (Object of the Invention) The object of the present invention is to
When it is necessary to change the focus detection area during control
To prevent the wrong area from being selected.
Focus adjustment equipmentPlaceTo provide. [0010] Means for Solving the Problems To achieve the above object
Therefore, the present inventionDef for each of multiple areas on the screen
Focus detecting means for detecting the amount of focus, and the focus detecting means
Driving means for driving the lens based on the output of the lens
Lens drive based on the focus detection result of the selected area.
Movements are repeated, and the results of multiple past focus adjustments
The image plane position after a predetermined time based on the
Plane position of the object to be focused and the image plane of the lens
Predictive control to drive the lens to match the position
The predictive control, wherein
The means is the default of the focus detection area used for the previous control.
If it is determined that the amount of scum is inappropriate for the prediction calculation,
When the object to be performed moves away, use the previously used focus
The area near the detection area is controlled as the area to be changed.
Within the range to detect a defocus amount suitable for prediction calculation.
When the object to be focused is approaching
In this case, the range in which the area is changed is not restricted
Detects the amount of defocus suitable for measurement calculation and drives the lens.
This is an automatic focusing device to be performed. [0011] BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Will be described. The following description of the present inventionFruitExampleAnd in the present invention
Examples of such reference technologiesThen, as shown in FIG.
Focus detection area (hereinafter, referred to as 5
ExampleAnd reference technology examplesAuto focus with
A camera using the point adjusting device will be described. A focus detecting device having a plurality of distance measuring points will be described.
Has already been disclosed by the present applicant,
The detailed description of the
The light beams that have passed through the exit pupil of the region
An image is formed on the in-sensor, and the relative positions of the two images are detected.
Know the phase of the focus detection of the shooting lens
This is a focus detection device having a difference type focus detection system. FIG. 4 is a block diagram of the present invention.ExampleAutomatic focus pertaining to
FIG. 2 is a block diagram illustrating a configuration of a camera including an adjustment device.
You. In FIG. 4, PRS is a camera control device.
For example, a CPU (central processing unit), ROM, R
One-chip microcomputer with AM, A / D conversion function
(Hereinafter referred to as microcomputer). Microcomputer PR
S is a camera sequence program stored in the ROM
Automatic exposure control function, automatic focus adjustment function,
Performs a series of camera operations, such as winding the lum. for that reason
In addition, the microcomputer PRS uses the synchronous communication signals SO, SI, S
CLK, communication selection signals CLCM, CSDR, CDDDR
To communicate with peripheral circuits and lenses in the camera body.
To control the operation of each circuit and lens. SO is the data output from the microcomputer PRS.
Data signal and SI are the data signals input to the microcomputer PRS.
And SCLK are synchronous clocks of the signals SO and SI. LCM is a lens communication buffer circuit,
When the camera is operating, supply power to the lens power supply terminal.
And the selection signal CLCM from the microcomputer PRS.
Is at a high potential level (hereinafter referred to as “H”).
And a communication buffer between the lens and the lens. That is, the microcomputer
PRS sets the lens communication buffer circuit CLCM to "H"
And transmits predetermined data from SO in synchronization with SCLK.
Then, the circuit LCM passes through the camera / lens indirect point,
The buffer signals LCK and DCL of SCLK and SO are
Output to At the same time, the signal DLC from the lens
The buffer signal is output as SI, and the microcomputer PRS outputs S
The above SI is used as data from the lens in synchronization with CLK.
input. SDR is a focus detection composed of a CCD or the like.
Circuit for driving the line sensor device SNS for
Controlled by microcomputer PRS using O, SI, SCLK
Is controlled. The signal CK is a clock for driving the CCD φ1, φ
2 for generating the signal INTEND
Informs microcomputer PRS that the accumulation operation has been completed
Signal. The output signal OS of the line sensor device SNS is
These are time-series signals synchronized with the clocks φ1 and φ2.
After being amplified by the amplifier circuit in the driving circuit SDR,
Is output to the microcomputer PRS. Microcomputer PRS is A
OS is input from the analog input terminal, synchronized with CK,
After A / D conversion by the internal A / D conversion function,
Store sequentially in the address. Similarly, the output signal of the line sensor device SNS
Is the AGC (automatic gain control) in the device SNS.
Control: output of sensor for Auto Gain Control)
The image signal is input to the circuit SDR and stored in the sensor device SNS.
Used for product control. [0022] The SPC is used to detect an object from a subject through a photographing lens.
Exposure control photometric sensor that receives light and its output
SSPC is input to the analog input terminal of the microcomputer PRS.
After A / D conversion, automatic
Used for exposure control (AE). DDR is a switch detection and display circuit.
Is selected when the signal CDDDR is "H", and SO, S
It is controlled by the microcomputer PRS using I and SCLK.
That is, based on the data sent from the microcomputer PRS,
Switch the display of the camera display member DSP
The on / off status of various operation members of the camera
Notify the icon PRS. The LED is focused as an example of the display member DSP
A light-emitting diode for display or out-of-focus
Out of focus is displayed by lighting and blinking. SW1 and SW2 are release buttons (not shown).
Is a switch that changes its state by operating
Switch SW1 is turned on by pressing the first stage of the button,
Subsequently, SW2 is turned on by pressing down to the second stage. My
The control PRS is turned on when the switch SW1 is turned on, as described later.
Performs photometry and automatic focus adjustment, and turns on switch SW2
Trigger exposure control and film winding. However
The switch SW2 is connected to the “interrupt input terminal” of the microcomputer PRS.
And the program when the switch SW1 is turned on.
Even during execution, an interrupt is generated by turning on switch SW2.
And immediately shift to the specified interrupt program.
I can do it. MTR1 is for film feeding, and MTR2 is for film feeding.
Mirror up / down and shutter spring charging
And motors MDR1 and MD
R2 controls forward rotation and reverse rotation. Microcomputer P
From the RS to the drive circuits MDR1 and MDR2.
Signals M1F, M1R, M2F, M2R
This is a control signal. MG1 and MG2 are shutter front curtains, respectively.
Rear curtain drive start magnet, signals SMG1, SMG
2. Power is supplied to the amplification transistors TR1 and TR2,
Shutter control is performed by the control PRS. However, the switch detection and display circuit DD
R, motor drive circuit MDR1, MDR2, shutter control
Does not directly relate to the present invention, and a detailed description thereof will be omitted.
You. A microcomputer in the lens (hereinafter referred to as a lens)
Input to LPRS in synchronization with LCK
The input signal DCL is transmitted from the camera to the lens FLNS.
Command data, and the lens operation
It is predetermined. The microcomputer LPRS in the lens performs a predetermined procedure.
Analyzes the instruction according to the focus adjustment and aperture control operation
And various parameters of the lens from the output DLC (open F
Number, focal length, defocus amount vs. lens extension
And the like). In this embodiment, an example of a zoom lens is shown.
And the camera sends a focus adjustment command
Focuses according to the amount of drive and direction sent at the same time.
The point adjustment motor LMTR is controlled by signals LMF and LMR.
Control to move the optical system in the optical axis direction to adjust the focus.
U. The movement amount of the optical system is the pulse of the encoder circuit ENCF.
Monitor with signal SENCF and microcomputer LPR in lens
It is counted by the counter provided in S, and the predetermined movement is
When completed, the microcomputer LPRS confidence in the lens
No. LMF, LMR set to "L" to brake motor LMTR
I do. For this reason, once a focus adjustment command is issued from the camera.
After the is sent, the microcomputer PRS in the camera
Until driving is completed, it is completely involved in lens driving
No need. An aperture control command is sent from the camera.
If the diaphragm is
Well-known stepping motor DMTR
Drive. However, the stepping motor is open system
Controllable encoders to monitor operation.
do not need. ENCZ is an encoder attached to the zoom optical system.
The microcomputer LPRS in the lens is an encoder circuit.
The signal SENCZ from the input circuit ENCZ is input for zooming.
Detect the position. The microcomputer LPRS in the lens has
Lens parameters at the camera position
When there is a request from the microcomputer PRS on the camera side,
Send parameters corresponding to the current zoom position to the camera
I do. In the above configuration, a power switch (not shown)
When the switch is turned on, power supply to the microcomputer PRS starts.
The microcomputer PRS reads the sequence stored in the ROM.
Start running the program. FIG. 5 shows the overall operation of the camera having the above configuration.
FIG. The execution of the program is started by the above operation.
Then, after step (001), step (002)
Proceed to. In step (002), the release button
State detection of switch SW1 which is turned on by one-step pressing
When the switch SW1 is turned off, the step
Go to step (003) and save to RAM in microcomputer PRS
Clear all set control flags and variables,
initialize. Steps (002) and (003) are steps
Switch SW1 is turned on or the power switch is turned off.
It is executed repeatedly until Thereafter, when the switch SW1 is turned on, the switch is turned on.
The process moves from step (003) to step (005). In step (005), the exposure is controlled.
Execute the "photometry" subroutine. The microcomputer PRS
The output SSPC of the photometric sensor SPC shown in FIG.
Input to the log input terminal, perform A / D conversion, and
Optimal shutter control value and aperture control value from digital photometric values
An operation is performed and the result is stored in a predetermined address of the RAM. Soshi
During the release operation, the shutter is
Control of aperture and aperture. Subsequently, in step (006), the "image signal
Execute the "input" subroutine. This subroutine
The row is shown in FIG. 6, but a detailed description will be given later.
In this step (006), the microcomputer PR
S is five sets of image signals from the focus detection line sensor device SNS
Enter the number. In the next step (007), the input image
Five ranging points (ranging areas) A, B,
Defocus amounts DFA, DFB, DFC of C, D, E,
Calculate DFD and DFE. The specific calculation method is described in this application
Disclosure by Japanese in Japanese Patent Application No. 61-160824
The detailed description is omitted here. In step (008), a "prediction calculation"
Execute the routine. This "prediction calculation" subroutine
Is used to correct the lens drive amount.
I do. In the next step (009), "Lens drive"
"Subroutine", and in the previous step (008)
The lens drive is performed based on the corrected lens drive amount.
This "lens drive" subroutine will be described in detail with reference to FIG. After the lens driving is completed, the step (00) is performed again.
The operation proceeds to 2) and the switch SW1 is turned off or not shown.
When the release button is pressed in the second stage, the switch SW2 is pressed.
Steps (005) to (009) are repeated until
Runs back and is good for moving subjects
Focus adjustment is performed. Now, when the release button is pushed further
When switch SW2 is turned on, the interrupt function
Even if there is any step, go to step (010) immediately.
To start the release operation. In step (011), lens driving is performed.
It is determined whether or not the line is being driven.
Go to 2), send lens stop command and stop lens
And proceed to step (013) to drive the lens.
If not, the process immediately proceeds to step (013). In step (013), the camera
The mirror of the return mirror is raised. This is shown in FIG.
The motor control signals M2F and M2R shown in FIG.
And executed. In the next step (014),
It is already stored in the “photometry” subroutine of Step (005).
Through the circuit LCM using the aperture control value set as the SO signal.
To control the aperture by sending it to the microcomputer LPRS in the lens
Let In steps (013) and (014),
It is determined in step (0) whether or not the
15), but the mirror up is a mirror
Can be checked with a detection switch (not shown) attached to
Aperture control, the lens is driven to a predetermined aperture value
Confirm by communication whether it has been done. If any are not completed
Waits at this step and continues to detect the state. Both
When the control end of the user is confirmed, the process proceeds to step (016).
Is done. In step (016), the previous step
It is already stored in the “photometry” subroutine of (005).
Control the shutter at the shutter time
Expose. When the shutter control is completed, the next step is performed.
In step (017), the diaphragm is opened to the lens.
Command in the above-mentioned communication operation to continue
The mirror is lowered at step (018). Mirror down
Are the motor control signals M2F and M2 in the same manner as the mirror up.
It is executed by controlling the motor MTR2 using R
You. In the next step (019), the above steps
Mirror down and aperture opening are completed as in step (015).
Wait for it. Mirror down and aperture opening control completed
Then, the process proceeds to step (020). In step (020), the mode shown in FIG.
By properly controlling the data control signals M1F and M1R,
One film is wound up. The above is the entire camera that has performed the prediction AF.
It is a sequence. Next, in step (006) in FIG.
The "image signal input" subroutine executed
This will be described with reference to the flowchart of FIG. This "image signal input" subroutine is a new subroutine.
This operation is performed at the beginning of the focus detection operation.
When the routine is called, through step (101)
Proceed to step (102). In step (102), the microcomputer PRS
Set the timer value TIMER of the self-running timer that it owns to R
By storing in the storage area TN on the AM, the focus detection
The start time of the output operation is stored. In the next step (103), the lens is driven.
The time intervals TM1 and TM2 in the quantity correction formula are updated. This
Before executing the step (103), the memory TM
1, TM2 in the last and previous focus detection operations
The time interval is stored, and the previous focus is stored in TN1.
The time when the detection operation was started is stored. Therefore, "TN1" in step (103)
−TN ”is the time interval of the focus detection operation from the previous time to the current time
Which is stored in the memory TM2. Also note
Immediately before executing “TM2 ← TN1-TN” to TM1
Data, that is, the focus detection time from the last two times to the previous time
Is stored. Then, the next focus detection operation is performed on TN1.
Therefore, the current focus detection start time TN is stored. This
In step (103), the memory TM1 is always stored two times before
Time interval data and the memory TM2
The interval data is stored. In the next step (104), the line
The sensor device SNS starts accumulation of the optical image. concrete
The microcomputer PRS communicates with the drive circuit SDR
Product start command ", and in response to this, the drive circuit
SDR is a value for the photoelectric conversion element of the line sensor device SNS.
Set the rear signal CLR to “L” to start the charge accumulation
You. In the following step (105), a self-running timer
Is stored in a variable TI and the current time is stored.
You. Then, in the next step (106), the
Detect the state of the input PEND terminal of the icon PRS,
Check whether the accumulation is completed. Drive circuit SDR accumulates
At the same time as the start, the signal INTEND is set to "L",
Monitor the AGC signal SAGC from the sensor device SNS,
When the signal SAGC reaches a predetermined level, the signal INTE
ND is set to “H”, and at the same time, the charge transfer signal SH is set for a predetermined time.
Set to “H” to transfer the charge of the photoelectric conversion element to the CCD
It has a structure to make it. In step (106), the END terminal
It is determined whether the child is "H" or not, and if "H", the accumulation ends.
Then, the process proceeds to step (110).
If it is "L", it means that the accumulation has not been completed yet.
Move to step (107). In step (107), the timer of the self-propelled timer
Stored in the above step (105) from the Ima value TIMER
The subtracted time TI is stored in the variable TE. Therefore,
In the several TEs, the time from the start of accumulation to this point, so-called
The accumulation time is stored. In the next step (108), the above variable
TE is compared with the constant MAXINT, and TE is MAXINT
If less, the process returns to step (106), and again waits for the accumulation to be completed
Become On the other hand, if TE exceeds MAXINT,
(109) to forcibly end the accumulation
You. Completion of forced accumulation from microcomputer PRS to circuit SDR
This is executed by sending the “storage end command”. Drive
The operation circuit SDR receives a command from the microcomputer PRS to display a command for terminating accumulation.
Is transmitted for a predetermined time period “H”
To transfer the charge of the photoelectric conversion unit to the CCD unit. The operation up to the above step (109)
Thus, the accumulation of the sensors ends. In the next step (110), line sensing is performed.
The image signal OS of the device SNS was amplified by the drive circuit SDR
A / D conversion of signal AOS and RA of the digital signal
M is stored. More specifically, the driving circuit SDR
Is a CCD in synchronization with the clock CK from the microcomputer PRS.
Generates drive clocks φ1 and φ2, and generates a line sensor device
SNS uses the clocks φ1 and φ2 to control the CCD section.
Is driven, and the charge in the CCD is output as an image signal to the output OS.
Are output in chronological order. This signal is applied to the drive circuit SDR
After being amplified by the internal amplifier, the microcomputer becomes AOS
It is input to the analog input terminal of PRS. Microcomputer PR
S is A / D synchronized with the clock CK output by itself.
The digital image signal after the A / D conversion is sequentially
M is stored at a predetermined address. Thus, the input of the image signal is completed.
And the "image signal input" subroutine at step (111).
Return the routine. Next, execution is performed in step (009) of FIG.
The “lens drive” subroutine performed is shown in FIG.
This will be described with reference to a flowchart. When this subroutine is called, the
In step (202), two data are communicated with the lens.
Input "S" and "PTH". "S" is for the taking lens
Yes, the relationship between the defocus amount and the focus adjustment lens extension amount
In the case of a single lens that is fully extended,
"S = 1" because the entire lens is a focusing lens.
In the case of a zoom lens, the encoder ENCZ
Detects each zoom position and zoom position by control circuit LPRS
Is determined according to. "PTH" is a focusing lens
Encoder ENC interlocked with the movement of the LNS in the optical axis direction
Repetition of the focusing lens per pulse output from F
It is a delivery amount. Accordingly, the lens drive amount to be adjusted for focus is changed.
Focused by calculated defocus amount DL, S and PTH
Convert the adjusting lens extension to the number of encoder output pulses.
The calculated value, the pulse number FP representing the so-called lens drive amount, is
It is given by the following equation. FP = DL × S / PTH In the next step (203), the above equation is executed as it is.
I have. In the following step (204), the above step
"FP" obtained in step (203) is sent to the lens to focus
Adjustable lens (in the case of the whole extension type single lens,
Command). In the next step (205), the communication with the lens is performed.
Lens drive amount FP commanded in step (204)
It is detected whether or not the drive has been completed.
Proceeding to step (206), this "lens drive" subroutine
Return the routine. This lens drive completion detection is performed as described above.
Encoder E with the counter of microcomputer LPRS
The NCF pulse signal is counted, and the count value
The above-mentioned communication determines whether or not the value matches the lens drive amount FP.
It is executed by detecting at. Next, in step (008) of FIG.
"Predictive operation" subroutine to be executedFirst reference technology example
Will be described with reference to the flowchart of FIG. When this subroutine is called, the
In step (302), accumulation of data necessary for predictive control is performed.
Counter COUNT for determining whether or not
It is determined whether or not to count up. [0079]First reference technology exampleThen focus more than 3 times
If detection data and lens drive data are stored,
That is, if “COUNT> 2”, the prediction calculation is possible.
No further counting up is necessary.
Step (304). Also, if “COUNT ≦ 3”
If COUNT is counted up in step (303)
And then proceed to step (304). In step (304), the current prediction calculation
We are updating the data for The data is
Times before and after the defocus amount DF2, DF1, last time
And the lens drive amounts DL2 and DL1 two times before. here
The lens drive amount DL is converted into an image plane movement amount.
You. Steps (305) to (313) are executed
For updating the data of the defocus amount DF3 of
In step (305), the position of the ranging point to be used is
It is determined whether the value of the memory AFP storing
If “AFP = 1”, the last used ranging point is
15 is A. In this case, step
Proceeds to (306) and adds the defocus amount of the distance measuring point A to DF3.
DFA is input to DF3, data is updated, and "AF
If “P = 1”, the process proceeds to step (307). In step (307), "AFP = 2"
Is determined, and if “AFP = 2”, the
Proceed to step (308) and focus on DF3
Input DFB to DF3, otherwise step
Move to (309). In step (309), "AFP = 3"
Is determined, and if “AFP = 3”, step
At (310), the defocus amount DF of the distance measuring point C is added to DF3.
Enter C, otherwise go to step (311)
I do. In step (311), "AFP = 4"
Is determined, and if “AFP = 4”, step
The defocus amount DF of the distance measuring point D is added to DF3 in (312).
D. Otherwise, measure in step (313).
The defocus amount DFE of the distance point E is input to DF3. Thus, when “AFP = 1”,
Is the distance measuring point A, when "AFP = 2", the distance measuring point B, "AF
When P = 3, the distance measurement point C is used. When AFP = 4, the distance measurement point C is used.
The distance point D and the distance measurement point E when “AFP = 5”
I am responding. In step (314), it is necessary for prediction
It is determined again whether or not the data has been accumulated,
Prediction calculation can be performed if "COUNT> 2"
And go to step (315);
The process moves to step (320). In step (315), continuous image plane movement is performed.
It is determined whether or not there is continuity.
Considering that 3 is data suitable for prediction calculation,
Proceed to (322), otherwise, DF3
Consider inappropriate data and proceed to step (316)
You. This continuity determination method will be described later.
The description here is omitted. In step (316), continuous image plane movement is performed.
Search for a focus point with high defocus amount
A "subroutine, the details of which will be described later. In step (317), the above step
At (316), there was a ranging point having continuity of image plane movement.
It is determined whether or not the image plane moves when “ANG = 1”.
That there was no continuous ranging point
Proceed to step (318), and when “ANG = 0”,
That there were distance measuring points suitable for prediction calculation
Then, the process proceeds to step (322). Step (318) is suitable for predictive control.
There was no distance measuring point, so to initialize predictive control
Reset the value of COUNT, and in step (319)
Resets the value of ANG. In the next step (320), the non-predicted state
"Change AF point" B to select the appropriate AF point when controlling
Execute the routine. Detailed description of this subroutine
Will be described later, and the description is omitted here. In the next step (321), the above step
Defocus amount DF of the ranging point selected in step (320)
3 is input to the current lens drive amount DL, and the process proceeds to step (32).
Proceed to 6). In steps (322) to (325),
By the prediction calculation using the following function, the lens drive amount DL
Calculate. In step (322), the values used for the prediction calculation are used.
The time lag TL is calculated, and in step (323),
The coefficient A of the quadratic term of the quadratic function is calculated, and step (32)
In 4), the coefficient B of the first-order term is calculated, and step (32)
In 5), the lens drive amount DL of this time is calculated from TL, A, and B.
calculate. In step (326), the lens drive amount
DL, open F-number FN of photographing lens and predetermined coefficient
δ (this embodimentAnd reference technology examplesThen, the permissible circle of confusion 0.035m
m) is compared with “| DL | <FN ·
δ ”, the process proceeds to step (327), and if not.
If so, the process returns in step (328). In step (327), the lens drive amount D
Since L is smaller than the depth of field, it is necessary to drive the lens
It is determined that there is not, "DL = 0", and step (328)
Go to and return this subroutine. FIG.According to an embodiment of the present invention"Continuity
Judgment "subroutine, predicted from the continuity of image plane movement
It is determined whether the data is suitable for control. In the step (402), two times before
The image plane movement speed V1 during focus detection, and the previous to current
The image plane moving speed V2 is calculated. In the next step (403), the image plane moving speed
A parameter VCX indicating the rate of change of the degrees V1 and V2 is calculated.
You. Then, in step (404), the value of VCX is positive.
It is determined whether the value of VCX is negative (VCX <0).
If not, proceed to step (406).
Go to step (405). In step (405), the value of VCX is
It is determined whether the value is smaller than a predetermined value CX1.
If “CX1”, it is determined that there is continuity of image plane movement,
Proceed to step (408); otherwise, step
Move to (406). Here, as the value of CX1,
The value is about 2.7, and the closer the VCX value is to 2, the more the image plane shifts.
The continuity of movement is high. In step (406), the difference between V1 and V2 is determined.
| V1-V2 | is smaller than a predetermined value CX2.
Image plane movement if "| V1-V2 | <CX2".
Is determined to be high continuity, and the process proceeds to step (408).
Otherwise, go to step (407). Thus, the process proceeds to step (407).
In this case, it is determined that there is no continuity of the image plane movement.
Yes, when the process proceeds to step (408), the prediction control
Image data with continuous image plane movement suitable for
And FIG. 1In the first reference example of the present invention,
PutThis is the subroutine "Change AF point A"
The current focus detection data detected at the AF points used
When sub data is determined to be inappropriate,
Change the ranging point used by the chin. At this time
The algorithm is adjacent to the left and right of the previously used AF point
Use a focusing point with high continuity of image plane position change.
When the last used AF point is at the right end
To the left, and to the far left, use the AF point on the right.
You. In step (502), two times before
The image plane moving speed V1 during the focus detection is calculated, and the next step is performed.
In step (503), the distance measuring point used last time is stored.
It is determined whether the memory AFP is 1 or not, and “AFP = 1”
(If the last used AF point is A) Step
Proceed to (504), otherwise step (506)
Move to In the step (504), the measurement used last time is executed.
Since the distance point was A, here it changes to the distance measurement point B on the right.
The defocus amount DFB of the ranging point B is added to DF3
Enter Then, in step (505), the
Changed the AFP value to 2,
Proceed to step (538). In step (506), AFP is 2
It is determined whether or not “AFP = 2” (the measurement used last time).
If the distance point is B), proceed to step (507),
If not, the process proceeds to step (516). In steps (507) to (515), the previous
Since the ranging point used twice is B (AFP = 2), the ranging point
Distance measuring points A (AFP = 1) and C (AFP =
3) Select a focusing point with high continuity of image plane movement from
In step (507), the defocus
Between the previous and current focus detections obtained using the
The image plane moving speed V2 is calculated, and in step (508),
The difference | V1−V2 | between the image plane moving speeds V1 and V2 is changed to VSA.
input. In the next step (509), the distance measurement point C
Previous to current focus calculated using defocus amount DFC
The image plane moving speed V3 during the detection is calculated, and the next step
In (510), the difference | V1− between the image plane moving speeds V1 and V3 is obtained.
V3 | to the VSC. In step (511), VSA and VSC
Are compared, and if “VSA <VSC”, step (51)
Proceed to 4), otherwise proceed to step (512)
No. Here, "VSA <VSC"
Is smaller than the difference between V1 and V2 using the data of AF point A.
First, the continuity of the image plane movement is high,
Conversely, it is said that the continuity is higher when using the data of the ranging point C
That is. In steps (512) and (513),
To change the ranging point to be used to A, add the ranging point A to DF3.
Enter the defocus amount DFA and enter 1 for AFP
You. In steps (514) and (515),
In order to change the ranging point to be used to C,
Input the scrap amount DFC to DF3 and input 3 to AFP
You. In step (516), whether the AFP is 3
Is determined, and if “AFP = 3”, step (51)
Proceed to 7), otherwise proceed to step (526)
I do. Steps (517) to (525)
As in steps (507) to (515), the
Measurements with high continuity of image plane movement between the focus detection points B and C on both sides
Changes have been made to the focus points, and a detailed description is omitted here.
You. In step (526), whether the AFP is 4
Is determined, and if “AFP = 4”, step (52)
Proceed to 7), otherwise proceed to step (536)
I do. Then, in steps (527) to (535),
The measurement is performed in the same manner as steps (507) to (515).
Continuity of image plane movement between the distance measurement points C and E on both sides of the distance point D
Is changed to a higher ranging point. The process that proceeds to step (536) is the process of “AF
P = 5 ", and in this case, the left side of the ranging point E
In order to change to AF point D,
Enter the scrap amount DFD in DF3 and enter 4 in AFP
You. As described above, change of the distance measuring point to be used
Is performed, the process proceeds to step (538). This step
In (538), the measurement changed by the continuity of the image plane movement.
Whether the distance data is suitable for predictive control
If it is determined and determined to be suitable, step (54)
0), otherwise go to step (539)
No. In step (539), it indicates that the change of the ranging point has failed.
Is input to the flag ANG, and at step (540)
Inputs 0 to the flag ANG. And these processes
When the processing is completed, the subroutine is executed in step (541).
Return Chin. FIG.In the first reference example of the present invention,
PutThis is a subroutine "Change AF point B",
Select the ranging point to be used for the control. In step (602), the center distance measuring point C
The defocus amount DFC is larger than a predetermined value JS1?
Is determined, and if “DFC> JS1”, the step is performed.
(Transition to 605, otherwise step (603)
Move to Here, the focus is set on the center ranging point.
That the subject is in front of the current position
Yes, the value of JS1 is about 0.2 mm. this
Rarely have an obstacle in the center of the screen.
In this case, it is determined that the subject is the main subject, and the process proceeds to step (605).
Input the defocus amount DFC of the ranging point C to DF3,
Enter 3 for AFP. In step (603), the center distance measuring point D
It is determined whether FC is smaller than a predetermined value JS2,
If “DFC <JS2”, proceed to step (606)
If not, go to step (604). Here, the value of JS2 is about -0.2 mm.
Degree value, the defocus amount is 0.2mm or more.
When the subject is behind the focus position, the main
It is determined that the distance is measured not for the body but for the background, and step (6)
06) The ranging point is changed in the subsequent steps. In step (604), the value of DF3 is
It is determined whether or not the value is smaller than the predetermined value JS3.
If | <JS3 ”, go to step (618), so
If not, the process proceeds to step (605). Here, the value of JS3 is 0.7 mm.
The defocus amount of the focus point used last time is too small.
Use the same AF point, otherwise use the center AF point
Is intended to be used. In step (606), the differential of the distance measuring point A is determined.
Enter the focus amount DFA in DFM and enter 1 in AFP
I do. Then, in step (607), the DFM value and
Compare the defocus amount DFB of the distance measuring point B, and select “| DFM
If | <| DFB |, go to step (608).
Otherwise, go to step (609). Step
In step (608), each value of DFM and AFP is
Update to a value. Steps (609) to (614) are the same as those described above.
In the same manner as in steps (607) and (608),
Comparison of defocus amount for C, D, and E
Update, and the DFM has the minimum defocus amount in the DFM
Is stored in the AFP and the AF point with the minimum defocus is recorded.
Remembered. In the step (615), the DFM and the predetermined
The value JS4 is compared, and if | DFM | <JS4,
Proceed to step (617); otherwise, step
Move to (616). Here, the value of JS4 is 0.7 mm.
The minimum defocus amount DFM is relatively small.
If it is determined that the distance of the main subject is measured, step (6)
17) Input DFM to DF3, otherwise use
In step (616) to initialize the ranging point to be
DF3 and AFP are changed to the value of the center ranging point C. As described above, thisFirst reference technology exampleso
Indicates that the data of the ranging point used last during prediction control is
If it is determined that it is not suitable for control,
If there is a ranging point suitable for predictive control, change to this ranging point.
The same subject is being measured.
The probability of changing to the ranging point is higher, and it is different as before
The probability of accidentally switching to the ranging point that is measuring the subject
It can be greatly reduced. [0129]FIG.FIG. 12 shows the present invention.2nd reference concerning
Technical examplesShowing the operation of the main part of the camera according to
It is. The operation and electric circuit of the whole camera areUp
Example described and first reference exampleIs the same as
soThe details are omitted. This secondReference technology exampleFeatures of non-predictive
In the control state, you can change the AF point from adjacent AF points.
That is to choose. FIG. 9 shows the secondReference technology example"Forecast
Operation "subroutine, and steps (708) to (7)
The flow other than 14) is the firstReference technology exampleSame as
Therefore, detailed description is omitted. When this subroutine is called,
Counter (COUNT) at steps (702) and (703)
Are counted up, and steps (704) and (70) are performed.
In 5), the data is updated. Step (705)
The "DF3 data update" subroutine of FIG.
The same processing as in steps (305) to (313) is performed.
The flow is shown in FIG. And step
In step (707), the continuity of the image plane movement is determined.
If it is determined that there is no, the process proceeds to step (708),
If not, the process proceeds to step (715). In the step (708), the above step (7)
05), the value of DF3 updated is inappropriate for predictive control
The search for a ranging point suitable for predictive control
Point change C ”subroutine, and a detailed description will be given later.
You. In step (709), the above steps
Flag whether or not the change of ranging point in (708) was successful
Judgment by ANG, if "ANG = 0", AF point
Move to step (715) because the change of
Otherwise, go to step (710)
In order to initialize the control, the value of COUNT is set to 0. So
Then, in step (711), the flag ANG is initialized.
You. In the step (712), the measurement used last time is executed.
Compare defocus amount DF3 of distance point with predetermined value JS5
If "| DF3 | <JS5", the step (71)
Go to 4), otherwise go to step (713)
move on. Here, the value of JS5 is a value of 0.7 mm,
If DF3 is smaller than a predetermined value, the same subject (main subject)
Body), it is highly likely that step (71)
Proceed to 4), otherwise distance measurement in step (713)
Make point changes. Step (71)3)Is the non-predictive control state
In the subroutine "Distance measurement point change D" to select the distance measurement point
Yes, the same subject (main subject) from adjacent ranging points
Distance measurement with small defocus amount that seems to be measuring distance
Search for points. A detailed description will be given later. In step (714), the measurement to be used this time is performed.
Input the defocus amount DF3 of the distance point to the lens drive amount DL
I do. Then, the subsequent flow, that is, step (7)
19) to (721) and (715) to (718)
Since it is the same as the first embodiment, the description is omitted here. Next, in step (705) of FIG.
FIG. 10 shows the “DF3 data update” subroutine.
This will be described with reference to the flowchart of FIG. In this subroutine, the distance measuring point used last time is used.
For inputting the defocus amount of
You. The algorithm for updating data is based on the first algorithm.
Since it is the same as steps (305) to (313) of the embodiment,
Here, the description is omitted. Next, in step (708) of FIG.
FIG. 11 shows a flow chart of FIG.
This will be described with reference to a chart. In this subroutine, distance measurement is performed in the prediction control state.
Used when changing points. The flow of the whole subroutine is as follows:
Reference technology exampleSimilar to the "Change AF point" A subroutine
Therefore, different parts will be described. In this subroutine, the AFP
The image plane shift is performed for the AF points on both sides of the AF point used twice.
It is configured to select ranging points with high continuity of movement.
You. However, if the last used AF point is at the left or right end
In this case, the adjacent inner (one side) distance measuring point is selected. In steps (902) to (937),
The selected AF point is stored in the memory AFM and the AF point
Is stored in the DF3. AFP and A
Other than the FM difference,Reference technology exampleIs the same as
The description is omitted here. In step (938), the above steps
The defocus amount of the selected AF point is suitable for predictive control
Is determined from the continuity of image plane movement, and predictive control is performed.
If so, go to step (939), otherwise
If so, the flow shifts to step (941). In the step (939), the distance measurement point is officially set.
Enter the AFM value in the AFP to make the change and
Flag AN indicating failure in changing the ranging point in step (940)
Reset G. In step (941),
Set the flag ANG indicating the change failure and set the value of DF3
"DF3 data update" subroutine to restore
Execute When the above processing is completed, step (94)
In 3), this subroutine is returned. Next, in step (713) of FIG.
The subroutine "Change AF point" D in FIG.
This will be described with reference to a chart. This subroutine is executed in the non-predictive control state.
Used to change ranging points. In this subroutine, the measurement used last time is
The defocus amount is small in the ranging points on both sides of the ranging point
Change to the AF point. However, the right or left edge measurement
If the focus point was used last time, each inner side
Are selected. In step (1002), whether AFP is 1
It is determined whether or not “AFP = 1” in step (1).
003), otherwise (step 1005)
Move to. In step (1003), the last used
Since the ranging point was A on the left end, the neighboring ranging point on the right
In order to make a temporary change to B, the default
Enter the focus amount DFB, and in the next step (1004)
Inputs 2 to the AFM. In step (1005)
Is determined whether AFP is 2 or not, and “AFP = 2”
If so, proceed to step (1006);
The process proceeds to step (1011). At step (1006), the last used
Since the AF point was B, the differential of AF points A and C on both sides was
Compare the amount of focus and find || DFA | <| DFC |
If so, proceed to step (1007);
The process proceeds to step (1009). Thus, Defoca
Select a AF point with a small distance. In steps (1007) and (1008)
DF is used to switch the temporary AF point to AF point A.
3. Input the defocus amount DFA of the distance measuring point A into the AFM 3.
Enter 1 in. Then, steps (1009), (1
In step 010), a temporary ranging point change is performed for the ranging point C.
Input the defocus amount DFC of the distance measuring point C to DF3
Then, 3 is input to the AFM. Steps (1011) to (1024)
Even in the low range, as described above,
A focus point having a small focus amount is stored in the AFM, and the
The defocus amount of the distance point is input to DF3. In the step (1025), the temporary ranging point change is performed.
The defocus amount DF3 of the adjusted ranging point and a predetermined value J
Compare S5, and if | DF3 | <JS5, measure the distance
It is determined that the change of the point is successful, and the process proceeds to step (1026).
Proceed, otherwise judge that the change of the AF point has failed
Proceed to step (1027). Here, the value of JS5 is 0.
This is a value of about 7mm, and if the same subject is
Based on the idea that the amount of defocus does not increase drastically,
The above processing is performed. In the step (1026), the distance measuring point is changed.
Has been successful, A
Input the value of AFM to FP. On the other hand, in step (1027),
Resets the DF3 value to the initial state because the ranging point change failed.
To return, execute the “DF3 data update” subroutine.
Run. When the distance measuring point is changed in this way, the scan is performed.
Return this subroutine at step (1028)
I do. Thus, the secondReference technology examplesThen, unforeseen
Even in the measurement control state, it is adjacent to the focus point used last time.
Since the range of change is limited to the AF points,
Prevents changing the AF point to the AF point that measures the object.
It is designed to stop. [0162]Features of the embodiment of the present inventionMoves the subject
It is also possible to change the limit when changing the AF point according to the direction
Therefore, relax the restriction when the subject approaches
And when you go away, be strict. This is because when the subject moves away,
Accidentally set the AF point to something farther away, for example, in the background.
Subject approaching while likely to change
In the case of, the probability that there is an obstacle closer to the subject is low,
The possibility of accidentally changing the ranging point for such obstacles is low.
This is because FIG. 13 shows the present invention.Example of"Forecast
Operation ”subroutine, and steps (1108) to
The flow other than (1111) is the secondReference technology exampleSame as
Therefore, description of common parts is omitted. In the step (1107), the last used
The defocus amount of the AF point is not
If it is determined that the measurement is not suitable for measurement control, step (110)
Proceed to 8) to change the distance measuring point to be used. In step (1108), two times before
The image plane moving speed V1 during the distance measurement up to is calculated. Soshi
In the next step (1109), it is determined whether V1 is positive or negative.
If V1 is positive, proceed to step (1110).
If V1 is negative, the process proceeds to step (1111).
You. This is because when V1 is positive, the subject is approaching.
The subject is approaching in this way.
To go to step (1110)
When proceeding, proceed to step (1111).
ing. Step (1110) is "change of ranging point E".
In the subroutine, detailed description will be described later, but all five
Among the AF points, select the AF point with the highest continuity of image plane movement.
This is a subroutine. At this time, the selected AF point
Predictive control with no defocus amount of continuity of image plane movement
If it is determined that the distance measurement point is not suitable for
Set lag ANG to 1. Step (1111) is the secondReference technique
Surgical caseThe same subroutine of "change distance measuring point C" is executed. In this subroutine, the measurement used last time
High continuity of image plane movement from focusing points adjacent to the focusing point
Select a new AF point. Then, the differential of the selected AF point
Suitable for predictive control due to lack of continuity of image plane movement
If it is determined that there is no distance measurement point, a flag A indicating failure in changing the focus detection point
Set NG to 1. The detailed subroutine flow is
Since it is the same as the second embodiment, the description is omitted here. When the above subroutine is completed, step
At (1112), it is determined whether or not the change of the ranging point is successful.
It is determined by the lag ANG. "ANG = 0"
For example, the change of the AF point was successful.
Returning to step (1118), the prediction control is continued. And
If "ANG = 1", it means that change of ranging point failed.
Initialize predictive control and perform non-predictive control.
To go to step (1113). As described above, depending on the moving direction of the subject,
It is effective to perform different AF point change processing.
We try to prevent erroneous changes efficiently. Also,,Distance change D "subroutine
IsExample of second reference technologyThe explanation here is omitted.
Abbreviate. Next, in step (1110) of FIG.
The subroutine "Distance measurement point change E" in FIG.
This will be described with reference to a flowchart. In this subroutine, an image is selected from all the distance measuring points.
Selects ranging points with high continuity of plane movement
You. In the step (1202), two times before
The image plane moving speed V1 during the distance measurement is calculated. Next step
In step (1203), when the distance measurement data of the distance measurement point A is used.
Calculates image plane moving speed VA between previous and current distance measurement
Then, in step (1204), V1 and VA are stored in the memory VS.
The difference | V1-VA | is input. In step (1205), measurement of distance measuring point B is performed.
Image plane shift between previous and current distance measurement using distance data
The dynamic speed VB is calculated, and in the next step (1206),
Input the difference | V1-VB | between V1 and VB to memory VSB
You. In step (1206 '), an initial value is set.
Input the defocus amount DFA of the distance measuring point A to DF3,
Input 1 to AFM. In step (1207), VS and VSB
Are compared, and if “VS <VSB”, the step (12)
09), otherwise go to step (1208)
Transition. Here, “VS <VSB” means that
Using the AF point A is more effective for moving the image plane than using the AF point B.
This means that continuity is high.
Proceed to step (1209) without updating data
The continuity of the image plane movement is better when using the data of AF point B
If higher, each parameter is set in step (1208).
Update to the one at distance measuring point B and proceed to step (1209)
No. In step (1208), the image plane is moved to the memory VS.
The speed change amount VSB is input, and the distance measurement point B data is input to DF3.
The focus amount DFB is input, and the distance measurement point B is indicated on the AFM.
Enter the value 2. In the step (1209), the distance measuring point C is used.
Image plane moving speed VC between previous and current ranging when using
Is calculated. Then, in step (1210), V1
│V1-VC│ is input to VSC. Next
In Step (1211), VS and VSC are compared, and “V
If “S <VSC”, the process proceeds to step (1213),
Otherwise, go to step (1212) and go to step (1).
Go to 213). In step (1212), step (1)
As in step 208), each value of VS, DF3 and AFM is measured.
Update to the value of point C. Steps (1213) to (1213)
At (1220), the same processing is performed for the ranging points D and E.
I do. As a result, measurement with the highest continuity of image plane movement is performed.
The distance point is stored in the AFM, and the defocus amount of the distance measurement point is calculated.
Stored in DF3. In step (1221), a series of image plane movements
Whether the focus point with the highest continuity is suitable for predictive control
If it is determined and appropriate, the process proceeds to step (1224),
Otherwise, go to step (1222). In the step (1222), it is suitable for the prediction control.
No change in the AF point
Set lag ANG to 1 and go to step (1223)
To return the value of DF3 to the initial value. In the step (1224), the distance measuring point is changed.
Was successful, the flag ANG indicating failure was reset to 0.
In the next step (1225), the focus point
In order to make the change, the value of the AFM is input to the AFP. When the above processing is completed, a step (12)
At 26), this subroutine is returned. In this wayEmbodiment of the present inventionSo, wrong
When a subject that is unlikely to change the AF point approaches
Does not limit the area where the ranging points can be changed.
Conversely, a moving subject that is likely to change the AF point incorrectly
For the body, I used the area where the ranging point can be changed last time
Try to limit the distance measurement point to the one next to the distance measurement point.
To effectively prevent incorrect ranging point changes.
The adverse effects of limiting the number of focus points used
Can be ThisExampleAre the five positions in the screen
I explained cameras that can detect focus, but more
For example, if there are 10 ranging points,
In this case, the distance between the distance measuring points becomes narrow. Then, the same subject
Since the number of ranging points for measuring the distance also increases,
Can use the AF point next to the previously used AF point.
However, this control range is expanded,
It is good to be able to use two ranging points and four ranging points
No. As described above, according to the present invention, the distance measurement used last time is used.
It is not limited to the AF point next to the point.
The present invention is not limited to the case where a focus detection point near the focus detection point can be used.
Clearly what works. The aboveExampleAccording to
Used when performing control to repeat focus adjustment
When it is necessary to change the AF point to be measured,
A focus point near or next to the focus point used last time
Error due to incorrect ranging point change
There is an effect that crops can be prevented. (Correspondence between Invention and Embodiment) Line Sensor
The device SNS, the drive circuit SDR, and the microcomputer PRS are the present invention.
, The microcomputer LPRS in the lens,
Focus adjustment motor LMTR and encoder circuit ENCF
The microcomputer PRS corresponds to the lens driving means of the present invention, and
Invention predictive controlBy meansEquivalent to. The above is a description of each configuration of the embodiment and each configuration of the present invention.
Although it is a correspondence relationship, the present invention is limited to the configurations of these embodiments.
Not specified, the function or implementation indicated in the claims
Any configuration that can achieve the functions of the example
It goes without saying that this may be the case. (Modification) The present invention relates to a single-lens reflex camera,
Camera, video camera, etc.
, But other optics and other devices,
What can be applied as a constituent unit
It is. [0194] [0195] As described above, according to the present invention,
IfThe focus detection area needs to be changed during predictive control
To select the wrong area when
It is possible to provide a focusing device that can perform the focusing. [0196]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart illustrating a “ranging point change A” subroutine in a first reference example of the present invention. FIG. 2 is a flowchart showing a “prediction calculation” subroutine in a first reference example of the present invention. FIG. 3 is a flowchart showing a “ranging point change B” subroutine in a first reference example of the present invention; FIG. 4 is a block diagram schematically illustrating a camera according to an embodiment of the present invention. FIG. 5 is a flowchart showing an overall schematic operation of the camera shown in FIG. 4 ; FIG. 6 is a flowchart illustrating an “image signal input” subroutine according to the embodiment of the present invention. FIG. 7 is a flowchart illustrating a “lens drive” subroutine according to the embodiment of the present invention. FIG. 8 is a flowchart illustrating a “continuity determination” subroutine in the embodiment of the present invention. FIG. 9 is a flowchart illustrating a “prediction calculation” subroutine in a second reference example of the present invention. FIG. 10 is a flowchart illustrating a “DF3 data update” subroutine according to the embodiment of the present invention and the second reference example . FIG. 11 is a flowchart illustrating a “ranging point change C” subroutine according to the embodiment of the present invention and the second reference example . FIG. 12 is a flowchart illustrating a “ranging point change D” subroutine according to the embodiment of the present invention and the second reference example . FIG. 13 is a flowchart showing a “budget calculation” subroutine in the embodiment of the present invention. FIG. 14 is a diagram showing a “distance measurement point change E” according to the embodiment of the present invention.
It is a flowchart which shows a subroutine. FIG. 15 is a diagram illustrating a state when a finder of a camera capable of detecting a focus in a plurality of areas is viewed. FIG. 16 is a diagram for explaining a case where a malfunction occurs in a conventional device. [Description of Signs] PRS microcomputer LPRS lens microcomputer SNS focus detection line sensor device SDR drive circuit LMTR focus adjustment motor ENCF encoder circuit

Continuation of front page (56) References JP-A-4-317018 (JP, A) JP-A-1-288816 (JP, A) JP-A-4-317016 (JP, A) JP-A-3-231710 (JP) JP-A-4-360114 (JP, A) JP-A-2-77046 (JP, A) JP-A-2-93419 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB G02B 7/28 G03B 13/36

Claims (1)

(57) Claims 1. A focus detecting means for detecting a defocus amount of each of a plurality of areas in a screen, and a lens driving means for driving a lens based on an output of the focus detecting means. And a lens driving operation is repeatedly performed based on the focus detection result of the selected area, an image plane position after a predetermined time is predicted based on a plurality of past focus adjustment results, and a focus adjustment after a predetermined time is performed. Predictive control means for driving a lens so that the image plane position of the object to be subjected to the image plane position of the lens coincides with the image plane position of the lens.
, When the defocus amount of the focus detection area as the previous control is judged unsuitable for prediction operation, to perform focus adjustment
When an object to be moved away, focus detection used last time
Restrict the area near the area to the area where the area is changed
The defocus amount suitable for the prediction calculation within the range
When the object to be focused is approaching
Forecast without limiting the range in which the area is changed
Detects the defocus amount suitable for calculation and drives the lens.
Autofocus system, characterized in that cause I.