JPH0581006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera having an automatic focus adjustment device for photographing two objects located at different positions in a state where both objects are in focus.

[Prior art]

When subjects A and B are located at different positions, find an intermediate position that internally divides the lens position that focuses on subject A and the lens position that focuses on subject B by a predetermined ratio, and then The aperture is determined by moving the lens to the desired position and dividing the amount of defocus between the lens positions to focus on subjects A and B by the circle of least confusion. The applicant of the present invention has proposed a camera having an automatic focus adjustment device that ensures that objects A and B at different positions are in focus within the depth of field in Japanese Patent Application No. 61-236841.

In this type of lens position adjustment method, as mentioned above, based on the amount of defocus between the respective lens positions for subjects A and B, the lens position that divides the amount of defocus internally by a predetermined ratio is determined. If there is no lens position to bring the subject B into focus and a lens position to bring subject B into focus, the lens cannot be moved to the internal position, and both subjects are in focus. The purpose of shooting cannot be achieved.

For example, when the lens is driven by the amount of def focus obtained by detecting focus on object B at the lens position where object A is in focus, the limit on the infinity side is reached before the driving for the amount of def focus is completed. In the case where the lens hits a certain position, the amount of defocus and focus between the position of the lens to focus on subject A and the position (infinity position) where the lens is moved to focus on subject B. The detected amount of defocus will be different. Therefore, in such a case, the lens cannot be moved to the original transition position (a position where the defocus amount as a result of focus detection is internally divided by a predetermined ratio), and the above-mentioned desired photographic purpose cannot be achieved.

To solve the above problem, when detecting the amount of defocus for object B with the lens in focus on object A, find the amount of defocus so that the lens hits the infinity end or the closest end. In such a state, it is conceivable to prohibit the calculation of the intermediate position and the aperture value, and to indicate that the control has become uncontrollable.

However, in the case of a subject that cannot be brought into focus even if the above-mentioned defocus amount moves from the lens stop position and the lens reaches the infinity end, as long as the lens is used, it will not be possible to bring it into focus. Therefore, as long as such a subject is to be photographed, the photographer cannot improve the photographing situation even if an uncontrollable instruction is issued. On the other hand, for the above-mentioned subjects, the best focus is when the lens is moved to the infinity end, and in such cases, the infinity end position is considered to be the in-focus position of the subject. Even after processing, the lens position and aperture can be controlled so that almost both objects are in focus. Conversely, if the amount of defocus that causes the lens to hit the close end is detected, the photographer can take actions such as moving to improve the shooting situation. Instruct the photographer to move or perform other actions,
It is preferable to instruct the photographer to perform the operation of detecting the amount of defocus for subject B again.

〔the purpose〕

The present invention has been made in view of the above-mentioned matters, and has a configuration in which a focus detection circuit performs focus detection on a first object, and a lens is driven by a lens drive circuit according to the focus detection result. to a first position where the lens is in focus, and with the lens in the first position, the focus detection circuit performs focus detection on the second subject; In accordance with the focus detection result, the lens driving circuit moves the lens to a second position where the second subject is brought into focus, and the lens is moved between the first position and the second position. A lens position control device is provided, which uses a calculation means to calculate an intermediate position at which the focus states of the first object and the second object are approximately equal in accordance with the amount of movement, and causes a lens drive circuit to move the lens to the intermediate position. and a detection means for detecting whether or not the lens has reached the closest end of the lens before reaching the second position when the lens moves from the first position to the second position; and the detection means A determination means is provided for determining that it is impossible to make the focus states of the first and second objects almost equal when the arrival at the closest end is detected, This makes it possible to notify the user that it is impossible to focus on two subjects at the same time.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of a camera equipped with an autofocus device according to the present invention. In the figure, PRS is a camera control device, for example, a one-chip microcomputer with internal ROM, RAM, and A/D conversion functions.
Camera operations such as automatic exposure control function, automatic focus detection function, and film winding/rewinding are performed according to programs stored in the camera, which will be described later.

Microcomputer PRS is a communication signal
SO, SI, and SCLK are used to communicate with peripheral circuits and lenses, and to control the operation of each circuit and lens.

SO is the data signal output from PRS, SI is
The data signal input to PRS, SCLK is the signal SO,
This is the SI synchronization signal.

LCM is a lens communication buffer circuit. When the camera is in operation, the lens power supply VL is applied to the lens, and the signal CLCM from the microcomputer PRS is at a high potential level (hereinafter abbreviated as "H"; low potential is (abbreviated as 'L'), there is a communication buffer between the camera and the lens.

Microcomputer PRS signal CLCM
When set to 'H' and sends predetermined data as an SO signal in synchronization with the SCLK signal, the circuit LCM transmits the buffer signals LCK, SCLK and SO signals through the specified camera-lens interface. Output DCL to lens. At the same time, the buffer signal of the signal DLC from the lens (the part surrounded by the dashed line) is output as an SI signal, and the computer
PRS inputs lens data as an SI signal in synchronization with the SCLK signal.

SDR is a drive circuit for the line sensor device SNS for focus detection, and is selected when the signal CSDR from the computer PRS is 'H'.
Controlled by computer PRS by SCLK signal.

For example, SNS is a pair of CCD line sensors CCD ₁ ,
This is a sensor device including CCD ₂ . φ1 and φ2 are CCD driving clocks generated by the drive circuit SDR in response to the clock CK from the computer PRS, SH is a signal for transferring the charges accumulated in the line sensors CCD ₁ and CCD ₂ to the transfer section, and CLR is a clear signal for clearing the accumulated charges of line sensors CCD ₁ and CCD ₂ , and each of these signals is formed by a drive circuit SDR controlled by a computer PRS.

The output signal OS of the sensor device SNS is clock φ1,
Sensor CCD ₁ outputs in time series in synchronization with φ2,
It is an image signal accumulated in each picture element of CCD ₂ ,
Each bit is output to CCD ₁ and CCD ₂ and sent to the circuit.
After being amplified by the amplifier circuit in the SDR, it is input to the computer PRS as an AOS signal. The computer PRS inputs the AOS signal from the analog input terminal, and in synchronization with the CK signal, converts it from A/D using its internal A/D conversion function and sequentially stores it at a predetermined address in the RAM.

The AGC signal, which is also an output signal of the SNS, is the output of the storage control sensor in the device SNS, is input to the circuit SDR, and is used to control the storage time of the sensors CCD ₁ and CCD ₂ .

SPC is a photometric sensor that receives light through a photographic lens, and its output SSPC is sent to a computer.
It is input to the analog input terminal of PRS, and after A/D conversion, it is used for automatic exposure control (AE).

DDR is a switch sense and display circuit, and is selected when the signal CDDR from the computer PRS is 'H', and communication with the computer PRS is controlled by the SO, SI, and SCLK signals. In other words, the camera display is switched based on the data sent from the computer PRS, and the switch SW ₁ is linked to the release button.
The switch status of the switch group SWS, which is turned on and off in conjunction with various operating members including SW ₂ , is communicated to the computer PRS.

MDR1 and MDR2 are drive circuits for film feeding and shutter charge motors MTR1 and MTR2, and signals M1F, M1R, M2F, M2R
Executes forward/reverse rotation of the motor.

MG1 and MG2 are the magnets for starting the shutter front and rear curtains, respectively, and the signals SMG1, SMG2,
The amplifier transistors TR1 and TR2 are energized, and the computer PRS performs shutter control.

In addition, switch sense and display circuit DDR,
Since the motor drive circuits MDR1, MDR2 and shutter control are not directly related to the present invention, detailed explanations thereof will be omitted.

In-lens control circuit synchronized with synchronization signal LCK
The signal DCL input to the LPRS is data of a command from the camera to the lens, and the operation of the lens in response to the command is determined in advance.

The control circuit LPRS analyzes input commands according to a predetermined procedure, performs focus adjustment and aperture control operations, and outputs various lens parameters (aperture f/) from the output DLC.
number, focal length, coefficient of defocus amount vs. extension amount, etc.).

The example shows an example of a single lens that extends entirely, and when a focus adjustment command is sent from the camera, the focus adjustment motor LMTR is activated according to the drive amount and direction sent at the same time. signal
The LMF and LMR are sent out, the motor LMTR is driven, and the optical system is moved along the optical axis to adjust the focus. The amount of movement of the optical system is monitored by the signal SENC of the encoder circuit ENC, and when the predetermined movement is completed, the signals LMF and LMR are set to 'L' to brake the motor LMTR.

When an aperture control command is sent from the camera, a well-known stepping motor operates in conjunction with the aperture mechanism according to the number of aperture stages sent at the same time.
Drives DMTR. Furthermore, since the stepping motor can be controlled in an open manner, it does not require an encoder to monitor its operation.

The circuit LPRS is provided with a memory that stores the parameters such as lens focal length information (focal length information depending on the zoom state in the case of a zoom lens) at a predetermined address.
In addition, the circuit LPRS is provided with a counter that counts the pulses as the monitor signal SENC, and further counts the number of pulses corresponding to the amount of defocus when driving the lens, which will be described later. When the count value changes by a value corresponding to the above-mentioned defocus amount by counting the above-mentioned pulse number, that is, when the count value changed by lens driving matches the value according to the defocus amount, the signals LMF and LMR are set to L. It has a control circuit that stops the motor LMTR. In addition, as described above, this circuit forms a lens stop signal when the motor control stops when the above count values match, and the lens is driven before the change in the count value due to lens drive reaches a value corresponding to the defocus amount. A signal forming circuit is further provided for detecting that the lens is in a stopped state and forming a lens drive disabling signal at this time. The lens drive failure signal is generated by determining, for example, whether or not the monitor signal SENC has been generated for a predetermined period of time or longer in a state where the change in the count value has not reached a value corresponding to the defocus amount. A lens drive disabling signal is generated when the signal is not generated for a predetermined period or more under certain conditions.

In addition, the above display is an LDE for displaying focus and focus detection failure or NG display, and furthermore, DEP ₁ and DPE ₂ described later.
It is assumed that the device has a display element such as a segment that performs display.

The operation of the camera configured as above will be explained using FIG. 2.

When a power switch (not shown) is turned on, power is supplied to the microcomputer PRS, and the computer PRS executes the stored program.

FIG. 2a is a flowchart showing the entire procedure of the above program. When execution of the stored program is started, each step is executed sequentially from step 1.

Step 1: It is determined whether depth mode is selected.

This judgment is made using the signal CDDR from the computer PRS.
is H, designates the circuit DDR, inputs the setting state of the mode selection switch provided in the input switch group SWS to the computer PRS as an SI signal, and determines the setting state of the mode selection switch. .

If the mode is set to normal mode, the process moves to step 2.

Step 2: The state of switch SW ₁ , which is turned on by the first step operation of the shutter button, is detected.

The operation to determine the status of switch SW ₁ is based on the switch group.
This is done in the same way as SWS.

When switch SW ₁ is on, steps 3 and 4 are executed, the process returns to step 1 again, and switch SW ₁ is turned on.
When the lens is off, all flags are set to 0 in step 5, a lens stop command is issued in step 6, and the process returns to step 1.

Therefore, when the mode is set to normal mode and the shutter button is not operated, steps 1→2→5→6 are repeated.

Suppose now that the mode is set to depth mode with the shutter button not being operated.

In this case, during the repetition of steps 1→2→5→6, it is detected in step 1 that the mode has shifted to depth, so the step shifts to step 7.

Step 7: Prohibit release operation.

Step 8: Set all flags except flag DEP ₁ to 0, and set flag DEP ₁ to 1.

Step 9: Determine the state of switch SW ₁ , and if switch SW ₁ is off, proceed to step 10 and subsequent steps; if switch SW ₁ is on, proceed to step 17.

Assume that switch SW ₁ is now off. In this case, a lens stop command is issued in step 10, and the setting state of the flag DEPDN is determined in step 12.

Since the flags other than flag DEP ₁ are set to 0 in step 8, the process moves to step 13, where flags DEPJF and DEPOK are set to 0, and the setting mode is determined again in step 14, and the depth mode is maintained. If the depth mode is released, the process moves to step 15. If the depth mode is released, the process moves to step 16. In step 15, it is determined whether the elapsed time of the internal timer exceeds a predetermined value. It is assumed that this timer starts its timekeeping operation after the depth mode is set.

If the time measured by the timer has not exceeded the predetermined time, the process goes to step 8 again, and if the time has exceeded the predetermined time, the process goes to step 16.

Unless the predetermined time has elapsed after the depth mode is set in steps 9 to 16 above,
Steps 9 to 15 are repeated, and if the switch SW ₁ is turned on within this predetermined time, the process moves to step 17. If the switch SW ₁ is not turned on within the predetermined time, or if the depth mode is canceled, the process proceeds to step 16, where all flags are set to 0, and the process returns to step 1 again.

Therefore, even if the depth mode is set once, if the shutter button is not operated within a predetermined time, the depth mode will be canceled and the mode will return to the normal mode.

Assume that the first step of the shutter button operation is performed within a predetermined time after the depth mode is set. In this case, as described above, the process moves to step 17 and the photometry subroutine is executed. In this photometry subroutine, the output SSPC of the photometry sensor SPC that measures light through the photographing lens is input to the computer PRS, digitized by the internal A/D conversion function, and the digital value is stored in the memory.

After the photometry subroutine is executed, the steps are 18.
Migrate to Migration.

Step 18: Reset the above timer and restart timing operation from the initial state.

Step 19: Detect the set state of flag DEPJF.

Now, in step 8, flags other than DEP ₁ are set to 0, so the process moves to step 20.

The AF control subroutine of step 20 is described after step 100 in FIG. 2b.

The first operation of the AF control subroutine under depth mode will be described below.

Step 200: Detect the set state of flag PRMV. Since this flag is also set to 0, the process moves to step 201.

Step 201: Detect the set state of flag DEPMV. This flag is also set to 0, and the step moves to 204, where it is determined whether or not the depth mode is set. Since the current mode is depth mode as described above, the step shifts to 205.

Step 205: Detect the set state of flag DEP ₁ . Since the flag DEP ₁ was set to 1 in step 8, the step moves to 206.

Step 206 is a focus detection subroutine,
The subroutine starts at step 300 shown in FIG. 2c.
Described below. Next, this subroutine will be described.

Step 300: Execute the image signal input subroutine.

In the image signal input subroutine, first, the computer PRS sets CSDR to H, selects the drive circuit SDR, and transmits the SO signal to the drive circuit SDR. The SO signal at this time is an accumulation start command, and in response to this command, the drive circuit SDR sends a CLR signal to the line sensor device SNS to clear the image accumulation signal of the CCD line sensor, and then performs an accumulation operation on the image. Image light beams incident through the photographing lens are incident on the CCD line sensors CCD ₁ and CCD ₂ of the line sensor device SNS _, respectively.
The image position on CCD ₂ is determined according to the focus state.
To be more specific, when the object is in focus, the same image pattern is projected at the same position on each sensor CCD ₁ and CCD ₂ , and when the subject is in focus or in the rear focus state, the same image pattern is projected on CCD _{1 and CCD 2} .
The image pattern on the CCD ₂ is projected at symmetrically shifted positions depending on the direction and amount of focus shift. Therefore, by detecting the amount and direction of positional deviation between the image patterns on the CCD ₁ and CCD ₂ , the direction and amount of out-of-focus can be detected.

After clearing the image signal, the image pattern projected to the position according to the focus state as described above is transmitted to each CCD ₁ ,
The CCD ₂ accumulates data for a predetermined time, and then the drive circuit
A signal SH and clocks φ1 and φ2 are supplied from the SDR to the sensor device SNS. The accumulation time of the above image pattern is the output of the accumulation control sensor in the SNS.
This is determined based on AGC.

When the signal SH and the clocks φ1 and φ2 are supplied to the sensor device SNS as described above, the sensor device
The image signals accumulated in each pixel of each sensor CCD ₁ and CCD ₂ from the output terminal of SNS are sent out sequentially in time series as output OS, amplified by the amplification circuit in the drive circuit SDR, and sent to the computer as signal AOS. Input into PRS sequentially. Computer PRS is the above signal
The AOS is sequentially converted into digital values using the internal A/D conversion function and stored in a predetermined RAM.

With the above operations, the image signal for each sensor corresponding to the image pattern on the sensors CCD ₁ and CCD ₂ is stored in the RAM as a digital value, and the image signal input subroutine is ended and the process moves to step 301.

Step 301: Execute the differential focus amount calculation subroutine. In this subroutine, the sensor CCD ₁ obtained in the above image signal input subroutine and
Based on digital values corresponding to the image pattern on the CCD ₂ , the amount and direction of deviation until in-focus is calculated as the defocus amount DEF. Since the specific method for calculating the amount of defocus is not directly related to this application, a detailed explanation thereof will be omitted.
Since the degree of coincidence between the image patterns of CCD ₁ and CCD ₂ is determined by the focus state, the digital values of each of the above-mentioned sensors corresponding to the pattern are compared and processed, and the degree of coincidence of the data is determined and calculated from the focus state. This is to obtain the amount and direction of deviation, that is, the differential focus amount DEF. Also, in this subroutine, the sensors CCD ₁ ,
Contrast CNT is also determined from digital values corresponding to the image pattern of CCD ₂ , and this contrast detection is also known. A detailed explanation thereof will be omitted.

Step 302: Set flags JF and AFNG to 0.

Step 303: Contrast CNT and constant value
Compare LCLVC, and when CNT<LCLVC, that is,
When the contrast is low, the flag AFNG is set to 1 in step 304, the focus detection subroutine is ended, and the process moves to step 207.

Further, when CNT>LCLVC, that is, when the contrast is sufficient, the process moves to step 305, where it is determined whether or not the calculated differential focus amount DEF is within a constant differential focus amount JFFLD that can be considered to be in focus.
When DEF<JFFLD, flag is set in step 306.
JF is set to 1, the focus detection subroutine is ended, and the process moves to step 207. If the above judgment indicates that DEF>JFFLD, the focus detection subroutine is ended without setting the flag JF to 1, and the process proceeds to step 207.

In the above focus detection subroutine, when the contrast is low, the flag AFNG is set to 1,
Also, when the contrast is sufficient and the amount of defocus is considered to be in focus, set the flag JF to 1,
Also, when the amount of defocus is larger than the range that can be considered to be in focus, the program returns without setting the flag JF to 1.

After the focus state is detected and determined in the focus detection subroutine, a display subroutine is executed in step 207. In this display subroutine, when the flag AFNG is set to 1, the computer PRS sets the CDDR signal to H,
The circuit DDR is designated, and a display signal as an SO signal is transmitted to the circuit DDR, and an LED for indicating that the focus cannot be detected provided on the display device DSP is turned on. Also, when the flag JF is set to 1, the focus display LED is lit in the same way.

After displaying the focus state in the display subroutine, the step moves to 208.

Step 208: Determine the set state of flag JF.

When flag JF is set to 1,
At step 209, the set state of flag DEP ₁ is determined. Since DEP ₁ is currently set to 1,
After executing step 210 and setting the flag DEPJF to 1, the program returns and moves to step 9 again.

Also, when flag JF is 0, the set state of flag AFNG is determined in step 211, and AFNG is set.
When is set to 1, the process returns and goes to step 9 again.

Further, when both flags JF and AFNG are 0, steps after step 212 are executed.

Step 212: Execute a lens drive amount calculation subroutine (referred to as FP calculation subroutine). The subroutine includes step 400 shown in FIG. 2d.
It will be described later.

Step 400: Input the "coefficient S of the amount of defocus versus the amount of projection" from the lens. This input operation causes the computer PRS to set the signal CLCM to H, designating the circuit LCM, and designating the circuit LPRS in the lens via the circuit LCM. Further, the signal SD is transmitted to the circuit LPRS as DCL via the circuit LCM. The signal SO at this time is a command to read the coefficient S, and the circuit LPRS uses the signal SO to read out the coefficient S.
The coefficient S stored in the RAM is transmitted to the circuit LCM as a signal DLC, and the circuit LCM receives the above signal
The DLC is input to the computer PRS as an SI signal, and the coefficient S is input to the computer.

Step 401: Input the "protrusion amount PTM per encoder pulse" from the lens. Applicable
The input operation of PTH is performed in the same manner as the coefficient S described above.

Step 402: Coefficient S and PTH input in each read operation above and calculated defocus amount DEF
Perform the calculation DEF*S/FPH with.

As mentioned above, FPH is the amount of output per encoder pulse, and the encoder ENC is composed of, for example, a pulse plate, which detects the amount of movement of the lens LNS and outputs one pulse for each unit of movement. There is.

Further, the coefficient S is a coefficient of the amount of defocus versus the amount of protrusion, and DEF*S indicates the amount of protrusion corresponding to the amount of defocus, that is, the amount of movement of the lens in response to the defocus amount. Therefore, DEF*S/FPH indicates the number of pulses from the encoder ENC that corresponds to the amount of defocus, and by moving the lens by the number of pulses FP, the lens is driven by the amount of the calculated defocus. Become.

After determining the number of pulses FP corresponding to the amount of defocus in the above FP calculation subroutine, the step moves to 213.

At step 213, a lens drive subroutine is executed. In this subroutine, the computer
Set the CLCM signal to H at PRS, specify the circuit LPRS as described above, and specify the number of pulses FP as described above.
is transmitted to the circuit LPRS as a signal SO. circuit LPRS
Then, the signal LMF or LMR is set to H in accordance with the above FP to drive the motor LMTR.

Note that the above FP is determined according to the amount of defocus, and also includes information on the direction of deviation until focusing, that is, the driving direction of the lens, and the signal LMF or LMR is set to H according to this driving direction information. The lens is driven in the focusing direction.

After starting to drive the lens in step 213, the step moves to 214, sets the flag PRMV to 1, ends the AF subroutine, and returns to step 9.

Now, when the focus is determined in the first AF control subroutine when switch SW ₁ is turned on for the first time in the depth mode, the process returns to step 9 after the focus is displayed as described above. Become. If the switch SW ₁ is kept on in this state, the photometry subroutine is performed again in step 17, the timer is reset in step 18, and the set state of the flag DEPJF is determined in step 19. At this time, the flag DEPJF is set to 1, so the step moves to 21, and the set state of the flag DEPOK is determined. Since the flag DEPOK is initially set to 0, the step advances to step 22.

Therefore, the initial switch SW ₁ in depth mode
In the AF control subroutine during the on operation of
When the focus is suddenly determined, the focus is displayed and then the process moves to step 22.

Further, when it is determined that focus detection is impossible when switch SW ₁ is turned on for the first time in depth mode, steps 9→17→18→19→20 are repeatedly executed as long as switch SW ₁ is turned on, and the focus detection operation is repeated. .

Also, if a lens drive instruction is given based on the amount of defocus until focusing in the AF control subroutine when switch SW ₁ is turned on for the first time in depth mode, switch SW ₁ will be turned on after the initial AF control subroutine is executed. If it is held, steps 9→17→18→19→20 are repeated again. At step 20 while repeating the above steps
In the AF control subroutine, the flag at step 200
Since 1 is detected by PRMV detection, step
202 is executed to determine whether the lens has stopped.

The operation for determining whether the lens has stopped will be described. In this embodiment, when driving the lens, the number of pulses FP representing the amount of movement of the lens is input to the circuit LPRS as described above, and pulses are sent out from the encoder ENC in accordance with the movement of the lens LMS, and the number of pulses from this encoder is It is counted by a counter in the circuit LPRS, and when it matches the input pulse number FP, the circuit LPRS sets the signals LMF and LMR to L and controls the motor LHTR to stop.

It is assumed that the pulses from the encoder are counted up or down depending on the driving direction of the lens. Since lens drive control is performed in this way, the above input pulse number FP
The pulses from the encoder and the motor match
The circuit indicates that a stop operation has been performed on the LHTR.
This can be determined within the LPRS, and this circuit generates a lens stop signal when the lens drive control described above is not performed.

Therefore, the computer PRS specifies the circuit LPRS as described above and reads out this lens stop signal to determine whether or not the lens has stopped in step 202.

In addition, if the lens hits the infinite end position and stops while driving the lens, the number of pulses from the encoder ENC counted by the counter above will not match the number of pulses FP above, and the lens will stop. Become. Therefore, in such a case, even if the counter and the number of pulses FP do not match, the encoder ENC will not generate pulses, and in the circuit LPRS, under the above conditions, the encoder ENC will not generate pulses for more than a predetermined time. When it detects that the lens is not being driven, the signals LMF and LMR are set to L, the motor is stopped, and a lens drive disabling signal is generated.This signal is stored in the RAM inside the circuit.During normal operation and abnormal operation This is used to determine whether the lens has stopped.

If the lens stop signal cannot be detected in step 202, that is, if it is determined that the lens is still being driven, the AF control subroutine is immediately terminated and the process returns to step 9 again.

Therefore, while the lens is being driven according to the amount of defocus, the above repeating steps are steps 9→17→18→19→20 (200→202).
will be repeated.

While the lens is being driven as described above, when the amount of lens drive, that is, the number of pulses from the encoder ENC, matches the number of pulses FP found in the FP calculation subroutine above, the number of pulses matches. The output LMF and LMR are set to L in the detection circuit LPRS, and the motor
The LMTR will stop and the lens will be driven by the defocus amount. Therefore, if the lens is driven by the defocus amount while repeating the above steps, it is determined in step 202 that the lens has stopped, so the flag PRMV is set to 0 in step 203, and thereafter, as described above, steps 204→ 205→
206 is executed.

At this time, since the lens has been driven by the amount of defocus as described above, when the focus detection operation is performed in step 206, it is determined that the lens is in focus, and the process then moves to steps 208→209→210.

Therefore, the first switch SW ₁ in depth mode
When the lens is driven by the ON operation, the lens moves until it is in focus on the subject, and once it is in focus, it moves to step 22 in the same way as the operation when the above focus judgment is made. do.

Furthermore, since the AF control subroutine is repeated as described above even when the focus cannot be detected, when the focus is no longer detected, the lens is driven to the in-focus position, and then the process proceeds to step 22.

To summarize the depth processing operation when the switch SW ₁ is turned on for the first time in the depth mode, the subject is once brought into focus and then the process moves to step 22 after the object is out of focus.

After bringing the subject into focus as described above, the process moves to step 22, where the set state of the flag DEP ₁ is determined. Flagg
Since DEP ₁ is set to 1 as mentioned above,
The step moves to 23.

Step 23: Display DEP ₁ .

This display is signaled by computer PRS.
Set CDDR to H, specify the circuit DDR, transmit the DEP ₁ display signal as an SO signal to the circuit DDR, and use the circuit DDR to send the signal to the segment in the DSP of the display.
Display DEP ₁ . This will notify the photographer that the first depth process has been completed.

After this, the step moves to 24, and the flag DEP ₁
is set to 0, DEP ₂ is set to 1, then the flag DEPOK is set to 1 in step 25, and the process returns to step 9.

After this, if the switch SW ₁ is kept in the on state, the steps shift from 17 to 18 to 19 to 21. At this time, the flag DEPOK was set to 1 in step 25, so after step 21, step 9 is executed again.
Move to. Therefore, as long as switch SW ₁ is on after the first depth processing is completed, steps 9 → 17 → 18 →
Steps 19→21 are repeated, and the lens continues to be held at the initially focused position. When the shutter button is released from this state and switch SW ₁ is turned off, steps 9→17→18→19→21 are repeated and the steps proceed from step 12 onwards. step
Processing after 12 is as described above, flag DEPJF,
DEPOK is set to 0, and it is determined whether the mode is held at depth or whether a predetermined time has elapsed since switch SW ₁ was turned off after the first depth processing, and the mode is returned to normal mode. or if switch SW ₁ is left off until the predetermined time has elapsed, proceed to step 16.
The process returns to step 1 via , and the depth mode is canceled.

Also, if the mode is held at depth and the release button is operated again within the above time, the switch will be released.
When SW ₁ is turned on, the step moves to 17 again and goes to 2.
The second depth processing is started.

The second depth processing will be explained below.

As described above, the process moves to step 17, where the photometry subroutine is executed, and at step 18, the timer is reset to restart time measurement, and the process moves to step 19. At this point, the flag DEPJF has been set to 0 in step 13 while switch SW ₁ is off, so step 19 is followed by step 19.
Twenty AF control subroutines are executed.

In the AF subroutine, step 200 is performed as described above.
will be held.

At this point, the flag PRMV is set to 0, and the step moves from 200 to 201. At this time, since the flag DEPMV is also set to 0, the step moves to 204, where it is determined whether the mode is depth, and since the mode is currently set to depth, the step moves to 205.
Flag DEP ₁ before starting the second depth processing
is set to 0 in step 24 as described above, so the step moves to 215.

Step 215: Determine the set state of flag DEP ₂ . At this time, flag DEP ₂ is set to step 24 above.
The step is set to 1 in the second step.
The process moves to step 216 in FIG. e, and the above-described focus detection subroutine is executed to determine the focus state for the subject at the time when switch SW ₁ is turned on for the second time in the depth mode.

A flag is displayed as a result of determining this focus state.
When AFNG is set to 1, that is, when the contrast is low and focus cannot be detected, step 217
This is detected and the process moves to step 218.

Step 218: Execute the NG display subroutine. This subroutine lights up the focus detection failure display LED in the same way as the display routine above.
End the AF control subroutine.

If the flag AFNG is not set to 1 in the focus detection subroutine in step 216, that is, if it is determined that the contrast is sufficient, the process advances to step 219 following step 217.

Step 219: It is determined whether the differential focus amount DEF obtained in the focus detection subroutine is greater than a constant value dc. As a result of this judgment |
When DEF |

Therefore, in the second depth processing, when it is detected that the contrast is low or that the amount of defocus is large, the AF control subroutine is immediately terminated and the process returns to step 9.

If switch SW ₁ is kept on in this state, the steps will move from 9 to 17 to 18 to 19 to 20 again, and this step will be repeated until the above focus detection results are different. When it is determined in the focus detection subroutine that the contrast is sufficiently high and that the defocus amount is |DEF|<dc, the process moves to step 220.

Note that the focus detection result at the first step 216 has sufficient contrast and |DEF|
When it is determined that <dc, the process immediately proceeds to step 220 without repeating the focus detection operation described above.

The reason why depth processing is not advanced in the second depth processing when the defocus amount is larger than a predetermined value is that if the subject in the first depth processing and the subject in the second processing are extremely far apart, This is because depth processing in which both objects are brought into focus is not performed with high precision, and processing in depth mode is virtually impossible.

When the process moves to step 220 as described above, the focal length information of the lens is stored in the memory at step 220.
Input to LSTFL.

To input this focal length information, set the signal CLCM to H in the computer PRS, specify the circuit LPRS via the circuit LCM as described above, and read out the focal length information stored in the circuit. executed.

Note that if the lens is a zoom lens, focal length information corresponding to its set zoom state will be read out.

After reading the focal length information in step 220 in this manner, the process moves to step 221.

Step 221: An aperture value that brings both subjects into focus when the first and second depth processing is performed is determined from the calculated amount of defocus.

That is, as shown in Fig. 3, if the lens can be brought into focus when the lens is positioned at DEP ₁ for subject A in the first depth processing, then 1
During the second depth processing, the lens moved to the DEP ₁ position.

In this state, if you perform the second depth processing on subject B, which will be in focus when the lens is moved to the DEP ₂ position, the second depth processing will result in the defocus from lens position DEP ₁ for subject B during the second depth processing. DEF is detected by the focus detection operation described above, and this amount of focus is determined as the lens position DEP ₁ .
Defocus amount between DEP ₂ .

As described above, the depth processing in the present invention involves moving the lens to position DEP ₃ , which internally divides the amount of defocus between two different subjects to 7/17 toward the closest side, and at this position, changing the amount of defocus between DEP ₃ and DEP ₂ . The value obtained by dividing the amount, that is, |DEP|×7/17 by the circle of least confusion 0.035 mm, is adopted as the control aperture. To explain in detail, in general, as mentioned above, if there is a subject A that will be in focus when the lens is positioned at DEP ₁ and a subject B that will be in focus when the lens is positioned at DEP ₂ , the position
Move the lens to the position DEP ₃ that internally divides DEP ₁ and DEP ₂ , and change the lens position DEP ₃ after the lens shift to the original focusing position DEP ₁ or DEP ₂ for one subject.
While keeping the lens at DEP ₃ , by dividing the defocus amount DEF′ between the
An aperture value that satisfies the depth of field that brings the two subjects A and B into focus at their original positions DEP ₁ and DEP ₂ can be obtained.

Therefore, in this application _, using this principle, the above calculation is performed as |DEF _| I'm looking for an aperture that creates a taut condition.
Note that the aperture at this time does not cover the depth for the position DEP ₁ on the infinity side, but considering the characteristics of normal lenses, the above depth does not originally cover the subject on the infinity side. In this application, the internal division point (DEP ₃ )
is set as the 7/17 position on the closest side.

In this way, the aperture value |DEF|×7/17×1/0.035 that brings both subjects into focus is determined in step 221, stored in the memory LSTFNO, and the process proceeds to step 222.

Step 222: It is determined whether flag JF is set to 1 as a result of the focus detection subroutine in step 216.

As a result, if the flag JF is set to 1, the process moves to step 223 and the flags DEPJF and
DEP ₂ Set JF to 1 and end the AF control subroutine.

In steps 222 and 223, for objects for which the setting of flag JF to 1 is detected in the second depth processing, the object in the second depth processing is set to approximately the same position as the subject in the first depth processing. , otherwise the step
Move to 223.

It is now assumed that the subject positions in the first and second shots are different, and the process has proceeded to step 223.

This step 223 executes the above EP calculation subroutine, whereby the number of pulses FP corresponding to the amount of defocus up to the subject in the second depth processing is determined, and the step moves on to steps 224 and thereafter.

Step 224: Set the flag DEPMV to 1.

Step 225: Input count value FCNT representing the current position of the lens.

As mentioned above, the circuit LPRS inputs pulses representing the lens drive amount from the encoder ENC, and when controlling the lens drive, these pulses are counted and the number of pulses FP is determined according to the defocus amount as described above. It is detected whether or not it matches. Therefore, the pulses from the encoder ENC are counted by the circuit LPRS and indicate a predetermined value, and this count value is sent to the computer.
Count value indicating the current lens position in PRS
Entered as FCNT. Also, the above count value of this circuit LPRS is sent as a signal by computer PRS.
By setting CLCM to H, the circuit operates as described above.
LPRS is designated, the above count value is requested as the SD signal at this time, and the count value is input to the computer as the signal SI.

Step 226: The lens is driven in the focusing direction based on the above-mentioned defocus amount in the same manner as in the above-mentioned lens driving subroutine. That is, the lens is driven from the lens position in the first depth process by the amount of defocus determined in the second depth process.

Step 227: The number of pulses FP corresponding to the above-mentioned differential focus amount obtained in the above-mentioned step 223 is input into the memory DEPFP.

Step 228: The current count value FCNT of the lens inputted before lens driving and the number of pulses FP according to the amount of defocus inputted to the above memory.
and input into memory STLPOS.

With this, the position information to which the lens should be moved is set in the memory STLPOS.

That is, as shown in FIG. 3, assume that the lens is at the DEP ₁ position in the first depth processing, and the count value at this time is N ₁ . Then, in the case where it is possible to focus on the subject in the second depth processing by moving the lens to position DEP ₂ in the second depth processing, DEP _1
The lens driving amount FP from DEP ₂ to
Suppose that we obtain

In this case, the above memory STLPOS has N ₂ + N ₁
is memorized. This value N ₁ + N ₂ means that the lens has DEP ₁
It shows the count value when the lens moves from DEP ₁ to DEP ₂ with respect to the counter value N ₁ when it is at , and becomes the count value at the target position to which the lens should move.

The above step 228 ends the execution number AF control subroutine and returns to step 9.

If switch SW ₁ is kept on in this state, steps 17, 18, and 19 are performed after step 9. At this time, assuming that focus determination has not been made in the AF control subroutine during the second depth processing, the process moves to step 20, and the AF control subroutine is executed again.

In this second AF control subroutine, the flag PRMV is set to 0, and the previous AF control subroutine is set to 0.
Flagged at step 224 of the AF control subroutine
Since DEPMV is set to 1, the steps proceed from 200 to 201 to 229, and in the same manner as step 202 described above, it is determined whether the lens has stopped or not, and if the lens has not stopped, the process returns.

Therefore, unless the lens has stopped, the steps 9→17→18→19→20 (200→201→229) are repeated, and when it is confirmed that the lens has stopped, the process moves to step 230.

Step 230: This step is the same as step 225 above, and the count value FCNT is input when the lens is stopped after the second depth processing.

Therefore, if the number of pulses FP found in step 223 in the second depth processing is N ₂ , the lens would normally be driven until N ₂ pulses are sent from the encoder ENC. Therefore, the count value in this state is the lens position DEP ₁ at the end of the first depth processing before the lens is driven.
Letting the count value of the counter in (Fig. 3) be N ₁ , it becomes N ₁ +N ₂ . The steps after this step are
Move to 231.

Step 231: Memory obtained in step 228
The count value representing the current lens position obtained in step 230 is subtracted from the value stored in STLPOS. As mentioned above, the value of the memory STLPOS represents the scheduled lens position when the lens is driven by the amount of defocus determined in the second depth processing after the first depth processing is completed.
Let the count value at the end of the depth processing for the second time be _N1 , and when the pulse corresponding to the amount of defocus from that position is _N2 , it becomes _N1 + _N2 .
The result of the subtraction becomes zero when the lens is driven by the amount of defocus.

Step 232: Detect the lens drive failure signal. This detection operation is performed in the same manner as the lens stop signal detection operation described above.

Now, if it is determined in step 232 that the lens has not stopped due to inability to drive, then the step is
Move to 233.

Step 233: It is determined whether the absolute value of the calculation result obtained in step 231 is 4 or more. As mentioned above, if the lens is driven by the exact amount of focus determined in the second depth process, the calculation result in step 231 will be zero.
When the lens is not driven by the amount of the above-mentioned defocus, or when the lens overruns due to inertia even if the motor stops after being driven by the defocus amount, the smaller the amount of drive is than the planned amount, or the larger the amount of overrun. The larger the value, the larger the above calculation result becomes.

Therefore, in this step, when the above calculation result is 4 or less, the differential focus amount is driven, and the step
It is assumed that the lens has been driven to the scheduled lens position determined in step 228, and the flag DEPMV is set to 0 and the flag DEPJF is set to 1 in steps 234 and 235, and the AF control subroutine is ended.

Also, in step 233, if the calculation result in step 231 is 4 or more, it is assumed that the lens has not yet moved to the scheduled lens position, and the lens drive instruction is issued again in step 236.
After driving the lens, return and end the AF control subroutine.

Assume that it is determined in step 233 that the lens has not yet been driven to the expected lens position, and after the lens is driven again in step 236, the AF control subroutine is terminated and the process proceeds to step 9.

At this time, if switch SW ₁ is held in the on state, steps 17→18→19→20 (200→
Steps 201→229) are executed until the lens stops, and once the lens stops, the above steps 230→231→
232→233 is executed again. Therefore, in step 233 as a result of re-driving, the calculation result in step 231 is 4.
If it is determined that the lens has moved to the scheduled position determined in step 228, steps 234 and 235 are executed; otherwise, the above operation is performed in step 233, and the lens is moved to the scheduled position determined in step 228. This process is repeated until it is determined that the process has moved to the calculated scheduled position. Therefore, these steps 200→201→229→230→231→232→233→236
This ensures that the lens is reliably moved to the scheduled lens transfer position determined in the second depth process. The above operation is an operation when it is determined in step 232 that the lens is not in a drive-incapable state, but in step 232, the lens has moved to a limit position such as the infinite position, and the lens drive has become disabled. If it is determined that this is the case, step 237 is executed following step 232.

Step 237: In this step, it is determined whether the lens has hit the infinite end position and the lens cannot be driven.

As for the above judgment method, since the defocus amount DEF also includes lens drive direction information as mentioned above, the above pulse number FP calculated based on DEF also has a positive or negative sign as information representing the drive direction. By detecting this code at the step, it is determined whether the lens is being driven toward infinity.

In this step, when the lens becomes unable to drive while being driven in the infinity direction, and it is judged that the lens has stopped immediately after hitting the infinity end, the step is stopped.
The process moves to step 234, and thereafter the process is performed in the same way as when the above lens driving is performed correctly.

Furthermore, when it is determined in step 237 that the lens driving direction is on the near side, that is, when it is determined that the lens is stopped at the close end, the flag DEP ₁ is set to ₁ in step 238. ₃ , DEPDN
After setting 0 to 0 and displaying NG on the display device DSP in step 239, the AF subroutine is ended.

Therefore, if the lens hits the close end when driving the lens during the second depth processing and the lens cannot be driven, that is, if the desired image cannot be taken even after depth processing, the lens cannot be driven at a greater depth. The processing is not performed, and the above-mentioned NG display is displayed to inform the photographer that the depth processing is impossible, and to instruct the photographer to start the depth processing again from the first time.

In addition, when the lens is stopped at the infinite end,
The reason why the lens is considered to have been driven normally during the second depth processing is that there is no infinite state beyond the infinite edge for the lens, so the depth processing must be stopped and then repeated again. In this case, the subject that is in focus at the infinite end of the lens is considered to be the subject at the time of the second depth processing, and subsequent depth processing is continued. This is to make it happen.

Furthermore, when driving the lens in the second depth processing, the reason why the lens is servo (closed loop) controlled to the predetermined position is that in the depth mode of the present application, the lens is moved to the position determined in the second depth processing. After that, from this position, we find a position to internally divide the defocus amount obtained in the second depth process into 10/17 x 7/17, and process to move the lens to the above internally divided position, so this is the second time. This is because the lens position in the depth processing must be driven by the exact amount of defocus described above.

Also, since the lens is servo-controlled during the second depth processing, even if switch SW ₁ is turned off while the lens is being driven during the second depth processing, the lens will always be moved to the correct lens position. I can do it. That is, when the switch SW ₁ is turned off during lens driving in the second depth processing, the step shifts from step 9 to step 10, and at that point the lens stops. Also, after this, while switch SW ₁ is off, repeat steps 9 to 15 and turn on the switch again.
When SW ₁ is turned on, the steps are 7→17→18→19→
Move to 20. At this time, the flag DEPMV remains set to 1, so the switch is not activated again.
When SW ₁ is turned on, the process moves to step 20, and when the AF control subroutine is executed, steps 200→201
→ 229 → 230 and the above-mentioned processing is restarted.
It is assumed that the lens stop signal is also generated when the lens is stopped by the lens stop command in step 10. Therefore, after switch SW ₁ is turned on again, the process proceeds to step 230, where the count value representing the lens position (lens stop position when SW ₁ is off) is input as FCNT, and that position and step 228 are entered. The lens is moved as described above by the difference from the planned position determined by the following steps. Therefore, even if you accidentally turn off switch SW ₁ while moving the lens during the second depth processing, you will have to turn it off again.
When SW ₁ is turned on, the lens driving process to the scheduled position is restarted, and the lens is always moved to the correct lens position.

When the lens moves to the expected position through the above operations, steps 234 and 235 are performed as described above, the AF subroutine is ended, and the process moves to step 9.

If switch SW ₁ is turned on in this state, the steps shift from 9 to 17 to 18 to 19. At this time, since the flag DEPJF is set to 1 in step 235, the step advances from 19 to 21, and since the flag DEPOK is set to 0 at this time,
Steps go from 21 to 22. Also, at this time flag
Since DEP ₁ and DEP ₂ are set to DEP ₁ = 0 and DEP ₂ = 1 in step 24 described above at the time of the second depth processing transition, the steps are 22 → 26 → 27 → 28.
Proceed to step 25, display DEP ₂ on the display DSP to indicate that the second depth processing has been completed, set DEP ₂ to 0, set DEP ₃ to 1, and set the flag DEPOK to 1 in step 25. , step 9 again
Move to. If switch SW ₁ is kept on in this state, then step 9 → 17 → 18 → 19
→21→9 will be repeated, and the lens will be 2
It is held at the position determined in the second depth process, and the second depth process is thus completed.

After this, turn off switch SW ₁ and then turn switch SW ₁ again.
When turned on, the steps shift from 9 to 17 to 18 to 19. At this time, since the switch SW ₁ is turned off as described above, the process at step 13 is carried out, and the flags DEDJF and DEDOK are set to 0. Therefore, the step moves from 19 to 20,
Execute the AF control subroutine again.

At this point, the flag DEPMV is set to 0 in step 234, so the AF control subroutine moves to steps 200→201→204→205, and the flag is set in steps 24 and 28.
Since DEP ₁ = 0, DEP ₂ = 0, and DEP ₃ = 1, step 205 is followed by step 205→
Move to 240 and execute step 240.

Step 240: Determine the state of flag DEP2JF. This flag is set to 1 only when step 223 is executed during the second depth processing, that is, when the subject during the first and second depth processing is approximately at the same position.

Therefore, the first and second shots for subjects in different positions
If the depth processing is done for the second time, the step
Move to 241.

It is assumed that the step has now moved to 241.

Step 241: Memory at step 227
The number of pulses FP input to DEPFP, that is, the number of pulses corresponding to the amount of defocus to the lens transition position obtained during the second depth processing, and the step when the lens is driven to the planned position in steps 233 to 235 above. Perform subtraction with the number of pulses found in step 231. That is, for example, as shown in FIG. 3, if the count value representing the lens position DEP ₁ during the first depth processing is _N1 , and the number of pulses FP corresponding to the amount of defocus during the second depth processing is _N2 , then the above steps are performed. The count value representing the lens transition position DEP ₂ scheduled for the second depth processing determined in step 228 is N ₁ +N ₂ .

In addition, in steps 230 to 236, as described above, the lens is driven until the planned lens position and the current position of the lens are within 4 pulses, so the count value representing the actual lens position DEP ₂ in the second depth processing is As shown in Figure 4, N ₁ +N ₂ ±α, 4≧α≧−
4, and has an error within ±α from the planned lens position.

Then, in step 231 above, the planned position (N ₁ +
N ₂ )−lens transition position (N ₁ +N ₂ ±α), and this ±α is obtained.

Therefore, in this step 241, the number of pulses _N2 corresponding to the amount of defocus obtained in the first depth processing is subtracted from the above ±α.
The actual lens movement amount N ₂ ±α between the lens position DEP ₁ after the first depth processing and the actual lens position after the second depth processing is determined, and this is input into the memory DEP ₂ FP.

Since the distance between the actual lens positions DEP ₁ and DEP ₂ is calculated in this way, even if the lens is stopped at the infinite end as described above, the distance between the actual lens positions DEP ₁ and DEP ₂ can be accurately calculated. This allows the amount of movement to be detected.

After the amount of movement of the lens positions DEP ₁ and DEP ₂ is determined in step 241, the sign of the defocus amount DEF from DEP ₁ to DEP ₂ determined in the second depth processing is determined in step 242. As described above, the defocus amount DEF also includes information representing its driving direction, and the direction of movement from the position DEP ₁ to the position DEP ₂ is determined by determining the sign of the DEF. In this embodiment, a positive sign indicates the driving direction toward the closest side, and a negative sign indicates the driving direction toward the infinite side.

Assuming that the lens positions are now in the relationship shown in FIG. 4, the lens is driven in the close-up direction when moving from DEP ₁ to DEP ₂ , so the defocus amount DEF is positive, and in this case, the process proceeds to step 243. Transition.

Step 243: DEP ₁ obtained in step 241 above
Find the number of pulses that internally divides the number of pulses representing the amount of movement between and DEP ₂ into -7/17.

As a result, the number of pulses corresponding to the amount of movement from DEP ₂ to DEP ₃ is determined as shown in FIG.

Further, when it is detected in step 242 that the drive is in the infinite direction, step 244 is executed instead of step 243.

In such a state, the relationship between DEP ₁ and DEP ₂ is as shown in FIG.

Therefore, in step 244, the number of pulses that divides the distance between DEP ₁ and DEP ₂ into 10/17 is determined, and this number of pulses is
This is the number of pulses representing the amount of lens movement from DEP ₂ to DEP ₃ .

By doing this, in the second depth processing of the lens, when the lens is driven in either the near or infinity direction, the lens position DEP _{3 will be set to DEP 3} , with the near side being 7 and the infinity side being divided into _10. The number of moving pulses can be calculated from the above lens position of the present application.
Migration to DEP ₃ is now possible.

In this way, in step 243 or 244 position DEP ₂
After determining the number of pulses from the encoder necessary to shift from DEP ₃ to DEP 3, the steps proceed to 224 and subsequent steps.

Therefore, after this, the lens is driven in the above steps in the same way as the lens drive during the second depth processing.
After moving from the position DEP ₂ by the number of pulses determined in steps 243 and 244 and moving to the above position DEP ₃ , the flag DEPMV is set to 0 again in steps 234 and 235.
DEPJF is set to 1.

That is, in step 227 executed in the third depth processing, the data from the position DEP ₂ obtained in steps 243 and 244 is stored in the memory DEPFP.
DEP is the number of movement pulses up to ₃ , and is the number of pulses for step 228.
Then, the count value representing the lens position of DEP ₃ will be stored in the memory STLPOS.

Therefore, after performing step 244 or 243, each of the steps 224 to 228 described above is executed, and the process proceeds to step 9. From then on, as long as switch SW ₁ is kept on, the lens of the second depth processing is applied. The same steps as driving 9→17→18→19→20 (200→201
→229) or 20 (200→201→229→230→231→232→
233→236) or 20(200→201→229→230→231→
232 → 237) is executed repeatedly and the memory is
The lens is driven until it reaches a count position within ±4 of the count value stored in STLPOS (position of DEP ₃ ), and when the lens moves to a position within ±4 pulse range of DEP ₃ , as shown above. Flag DEPMV becomes 0 at steps 234 and 235.
DEPJF is set to 1 and lens driving in the third depth process is completed.

Furthermore, even when the lens is driven during the third depth processing, servo (close) control is used to reach the scheduled lens position, and even if switch SW ₁ is turned off once while the lens is being driven, the lens will still be driven to the scheduled position. At the same time, if the lens moves to the limit position on the close side and becomes unable to drive, the depth processing will not proceed and an NG display will be performed, and if the lens stops at the infinite position, the lens will be held at that position. This is used to perform the subsequent depth processing.

After completing the lens driving in the third depth processing in this way, the steps progress from 9 to 17 to 18 to 19. At 19, the flag DEPJF of 1 is detected, and the step advances to 21 and thereafter, and the flags DEPOK,
The set state of DEP ₁ , DEP ₂ , and DEP ₃ is detected.
At this point, flags DEPOK, DEP ₁ and DEP ₂ are set to 0 and DEP ₃ is set to 1, so the process proceeds to steps 21→22→26→29→30. In step 30, set the flag DEP ₃ to 0,
After setting DEPDN to 1, the program proceeds to step 31 and executes the DAV calculation subroutine shown in FIG. 2f.

In the DAV calculation subroutine, step 500 is first executed.
Execute.

Step 500: Lens focal length information is entered into memory NWFL. Detection of this focal length information is performed in a manner similar to step 220 described above.

Step 501: Subject A is brought into focus by shifting the lens to DEP ₁ during the first depth processing determined in step 221, and brought into focus by shifting the lens to DEP ₂ during the second depth processing. The aperture value that guarantees the depth to bring both subject B into focus, that is, the aperture value input into the memory LSTFNO in step 221 (referred to as LSTFNOAV) and the memory mentioned above.
Calculation of focal length information (referred to as f ₁ ) stored in LSTFL and focal length information (referred to as f _o ) stored in memory NWFL LSTFNOAV×
(f _o /f ₁ ) ² is performed and this is set as the control aperture AVdep.

This calculation is performed in order to be able to supply an aperture with a depth that keeps both objects in focus even if the zoom ratio of the lens is varied during the depth processing and the focal length information changes.

The above aperture value LSTFNOAV is a value determined based on the amount of defocus when the focal length is _f1 ,
The amount of defocus has a characteristic that in relation to the focal length, it changes four times when the focal length doubles.

In other words, if DEF is the amount of def focus when focus is detected at lens position DEP ₁ with focal length f ₁ , then 4DEF is the amount of def focus when this same subject is detected at focal length 2 f ₁ , and the above aperture value LSTFNOAV Also, if the focal length changes by a factor of 2, it changes by a factor of 4.

Therefore, when the focal length at which the above-mentioned aperture value LSTFNOAV was calculated and the focal length at the time of shooting change due to zoom operation, etc., the above-mentioned aperture value LSTFNOAV
Even if you perform aperture control with , it is no longer possible to guarantee the depth of field when both subjects are in focus.

Therefore, in this application, LSTFNOAV×(f _o /f ₁ ) ² is set as the control aperture value AVdep, and when the focal length changes twice compared to when calculating LSTFNOAV, the aperture is set to 4.
We are looking for an aperture value that guarantees that both subjects are always in focus, regardless of zoom operations.

After this step 501, the step proceeds to 502.

Step 502: In this step, it is determined whether the lens attached to the camera is a zoom lens or a fixed focus lens.

This discrimination operation is performed by the computer PRS in the same way as the above-mentioned transmission of focal length information from the lens to the camera.
The circuit LPRS is designated at , and the zoom lens information or fixed focus lens information stored in the RAM in the circuit is read out and input to the computer PRS, and the above determination is made based on this input information.
Note that since the zoom lens or fixed focus lens information is determined for each lens, the zoom lens information is stored in the RAM of the lens for the zoom lens, and the fixed focus lens information for the fixed focus lens is stored in the RAM of the lens.

If it is determined in this step that the attached lens is a zoom lens, step 503 is executed and a constant value AV _ZM is added to the aperture value AVdep to obtain a correction control aperture value AVdep'. By adding this constant value AV _ZM , the aperture value becomes an aperture value that is slightly closer to the aperture value than the calculated aperture value AVdep, that is, an aperture value that has a deeper aperture depth.

This addition process is to absorb the error with respect to the calculated aperture value AVdep. That is, the above
In determining AVdep, even if there are various error factors, the above-mentioned error is corrected by setting the actual control aperture to a deeper aperture value.

Further, if it is determined in step 502 that a fixed focus lens is attached, step 504 is executed instead of step 503.

In this step 504, a constant value AV _SNG is added to the above aperture value AVdep to determine the correction control aperture value.
We are looking for AVdep′. This addition process also has the purpose of error correction similar to that of the zoom lens described above.

Note that the constant value is in the relationship AV _SNG < AV _ZM . The reason why AV _SNG and AV _ZM are set in this relationship is that zoom lenses include more error factors than fixed focus lenses, so the amount of correction for them is increased.

After determining the correction control aperture AVdep' in the above step, the step moves to 505.

Step 505: Find an integer J that satisfies J≦(4·log AVdep′/log ² +1)<(J+1) (1).

J is a value twice the apex value, and by determining this J, an apex aperture value with an accuracy of 1/2 stop of the apex value can be obtained.

In other words, the above formula (1) is a modified formula of (2 ^1/4 ) ^J-1 ≦AVdep′ < (2 ^1/4 ) ^J ……(2), and J that exactly corresponds to AVdep′ is To find it, J can be found using (2 ^1/4 ) ^J = AVdep′...(3). In this case, J is a value that includes not only integers but also decimals, and if J is calculated in (1) based on the above equation (2), the decimal part of J calculated using the above equation (3) will be rounded up.

Therefore, the aperture value J obtained using formula (1) is twice the apex value of AVdep' and is rounded up with 1/2 stop precision, indicating the aperture value on the narrower side. Further correction for error absorption is performed in the step processing. Thereafter, the process proceeds to step 506, where the J obtained in step 506 is processed by 2 ^J/4 and converted into a real number of aperture value for each 1/2 stop apex.

In addition to the purpose of the above-mentioned error absorption, the processing in step 505 is to match the mechanically controlled number of stages of the aperture of the camera, and since an aperture value of 1/2 stage of the apex is obtained, As the number of control stages, 1/2 ⁿ stage precision such as 1/8, 1/4, 1/3, etc. can be used.

When the DAV calculation subroutine is completed as described above, the process moves to step 32 to perform the DAV display subroutine. This subroutine is
This is a routine for displaying the real number of apertures obtained in the DAV calculation subroutine described above, and the display operation is performed in the same way as the display operation as described above.

When step 32 is performed, the process moves to step 33 to permit the release operation, moves to step 25, sets the flag DEPOK to 1, and returns to step 9.
Therefore, if switch SW ₁ is kept on in this state, the steps will be 9→17→18→19.
→Repeat step 21. Also, in this state, even if switch SW ₁ is turned off, steps 9→10→12→14→15 are repeated, and even if switch SW ₁ is turned on again, steps 9→17→18→19→21 are repeated. Repeated.
Therefore, even if the switch _SW1 is accidentally turned off after all depth processing is completed, the depth processing results will be maintained as they are.

When the second step of the shutter button is operated in this state, the release operation process in the AE control subroutine in step 3 is performed in the interrupt process, and the aperture signal is sent to the computer PRS according to the aperture value J determined by the above calculation. It is transmitted to the circuit LPRS through the circuit LCM as the SO signal of the step motor
The DMTR is driven, and the aperture linked to the motor is stopped down in accordance with J above, and the shutter release operation is performed. The shutter value will be controlled based on the shutter value determined based on the above.

With the above operation, in depth mode, the lens is set to a focus position that divides subjects at different positions into 7 on the close side and 10 on the infinity side, and the aperture is used to ensure that both subjects are in focus. Photographs will be taken at an aperture of .

In addition, in the case of the second and third depth processing described above, the actual driving amount of the lens is determined based on the number of pulses determined according to the amount of defocus obtained in the second depth processing, and the method of this actual driving amount is calculated. Since the lens is driven, even if the zoom ratio changes during depth, or even if the lens hits the infinity end, the lens will accurately move to the 7/17 internal dividing point of both subjects as described above. This means that it is possible to do so.

In addition, in depth mode, transition to release operation by turning on switch SW ₂ is prohibited until the third depth processing is completed, so even if you accidentally operate the second step of the release button while in depth mode. Subsequent depth processing can be executed, and even if the shutter button is erroneously operated until the depth mode ends, the mode is maintained.

In addition, in the embodiment, the counter that counts the pulses from the encoder ENC counts up and down the input pulses, and always indicates the value representing the lens position after the lens is driven.Furthermore, when driving the lens by the amount of defocus, the counter counts the input pulses up and down, and when driving the lens by the amount of defocus, the counter counts the pulses before the lens is driven. Although the lens drive amount is controlled to be the defocus amount by determining whether the change in the count value from the value has reached a value corresponding to the defocus amount, other methods can be used to control the lens drive amount. You may do so.

Further, a limit switch may be provided at each limit end as a method of detecting when the lens hits the infinite end or the closest end position.

Also, a method for determining whether or not the lens will hit the limit edge when the lens is driven based on the second defocus amount is to compare the calculated defocus amount, the current lens position, and the distance to the lens limit edge. In this case, absolute value information must be detected from the lens as current position information of the lens.

〔effect〕

As described above, in the present invention, when the lens hits the close side during the second depth processing, the subsequent depth processing is canceled and a warning is issued, and the state where the lens hits the infinity side is canceled. When this occurs, normal depth processing is allowed, so it is possible to provide a camera suitable for depth processing in which different subjects are brought into focus.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the camera of the present invention, FIGS. 2a to 2f are explanatory diagrams showing programs built in the computer PRS of the embodiment of FIG. 1, and FIG. FIGS. 4 and 5 are explanatory diagrams for explaining the operation of the embodiment shown in FIG. PRS...computer, LRRS...control circuit, LCM...buffer circuit, DMTR...aperture control motor.

Claims (1)

[Claims] 1. A focus detection circuit performs focus detection on a first object, and according to the focus detection result, a lens drive circuit moves the lens to a first position where the first object is in focus. the focus detection circuit performs focus detection on the second subject with the lens located at the first position, and the lens is moved by the lens drive circuit according to the focus detection result. The second subject is moved to a second position where the second subject is in focus, and the first subject and the second subject are moved in accordance with the amount of lens movement between the first position and the second position. a lens position control device for calculating an intermediate position where the focal states of the lenses are substantially equal to each other using a calculation means, and moving the lens to the intermediate position by a lens drive circuit, and moving the lens from the first position to the second position. a detection means for detecting whether or not the lens has reached the closest end before the lens reaches the second position during the transition; 1. A camera comprising a determination means for determining that it is impossible to make the focal states of the first and second subjects substantially equal.