JPH0558173B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic focus adjustment method for a camera, and more particularly to an automatic focus adjustment method for a camera that performs focus adjustment while emitting auxiliary light to illuminate an object.

PRIOR ART A technique that adjusts the focus while emitting an auxiliary light when it is determined that the focus detection result without the auxiliary light is emitted is disclosed in, for example, Japanese Patent Application Laid-Open No. 1983-1999.
It is known as No. 126023 etc.

Problems to be Solved by the Invention However, there is no known example that considers processing at the final stage on the premise that focus adjustment by emitting auxiliary light is repeated multiple times.

SUMMARY OF THE INVENTION An object of the present invention is to provide a self-special focus adjustment method that can rationally perform the final process when focus adjustment by emitting auxiliary light is repeated multiple times.

Means for Solving the Problems In order to achieve the above problems, the automatic focus adjustment method of the present invention focuses based on the focus detection result in the final stage of focus detection by emitting auxiliary light. The step of calculating the driving amount of the photographing lens necessary for A step of driving the photographing lens based on the drive amount and displaying that the focus state has been reached after the end of driving, and a step of comparing the above, and if the calculated drive amount is larger than a predetermined value, the photographing lens is moved. The main step is a step for issuing a warning without driving the motor.

Effect According to the automatic focus adjustment method described above, the drive amount obtained in the last focus detection is compared with a predetermined value,
The next operation is controlled based on the comparison result.

Embodiment FIG. 1 is a block diagram showing the basic configuration of a camera using the present invention, and numeral 1 indicates a photographic lens. The brightness distribution of the object light transmitted through the photographing lens 1 is measured by the measuring section 2. The detecting section 3 determines the direction and amount of deviation (in-focus state) of the photographing lens based on the brightness distribution signal from the measuring section 2. get the signal. Then, the driving means 4 drives the motor 5,
When the lens 1 is moved, a signal corresponding to the amount of movement (drive) is outputted from the lens 6, and when a signal corresponding to the amount of shift is outputted, the confirmation means 7 stops the operation of the driving means 4.

The switching means 10 selects a mode in which the auxiliary light is emitted by operating the auxiliary light irradiation means 8 and 9 (hereinafter, the irradiation of the auxiliary light will be referred to as preliminary flash or preliminary illumination, etc. to distinguish it from the flash light emitted during photographing). During measurement, the preliminary irradiation drive means 9 causes the preliminary irradiation means 9 to emit light in response to a measurement signal from the control means 11. When a mode in which preliminary irradiation is not performed is selected, the control means repeatedly outputs operation signals to the measuring means 2, the detecting means 3, and the driving means 4 even after the confirming means 7 outputs a signal to stop the lens 1. On the other hand, in the preliminary irradiation mode, once the confirmation means 7 confirms that the lens 1 has reached the in-focus position, the control means controls the measurement means 2, the detection means 3, the drive means 4, and the preliminary irradiation means 8 and 9. does not transmit operating signals. Therefore, subsequent focus adjustment is prohibited.

FIG. 2 is a circuit diagram showing the entire camera system to which the present invention is applied. Light receiving part FMD is CCD
(Charge Coupled Device) and has two rows of light-receiving elements, each of which is a light-receiving section that receives visible light including near-infrared light from the subject light from the exit pupil of the photographic lens. . Note that various optical systems for receiving light have been proposed and are therefore omitted here, but for example, the one shown in Japanese Patent Laid-Open No. 57-49841 may be used. COC is a control circuit that controls the operation of this light receiving section FMD. MCO1 is a microcomputer (hereinafter referred to as microcomputer) for automatic focus adjustment, and MCO2 is for controlling camera operation. First, the photometry operation based on the above portions will be explained.

When the terminal O3 of the microcomputer MCO1 becomes "High", a "High" pulse is output from the terminal φR of the control circuit COC, and the analog switch AS2 becomes conductive.
The multiple charge storage parts of CCD and FMD are connected to terminal ANM.
is charged to the output voltage of the constant voltage source E1. Then, when the terminal φR becomes "Low", charges corresponding to the amount of light received by each light receiving section are accumulated in the charge storage section. At this time, a signal corresponding to the accumulated charge by the monitor light receiving section (not shown) in the CCD and FMD is output from the terminal ANM. At this time, since the terminal φR is "Low", the analog switch AS1
is conductive, and the output from the monitor light receiving section is given to the inverting input terminal of the comparator AC1.
As charge accumulates, the output voltage gradually decreases. At this time, if the mode does not perform flash preflash by the electronic flash device, the terminal O
1 becomes "Low", the analog switch AS3 becomes conductive, the output voltage of the constant voltage source E2 becomes "Low", and the terminal O1 becomes "Low" if the mode is to perform flash preliminary light emission.
is “High” and analog switch AS4 conducts.
The output voltage of constant voltage source E3 is applied to the non-inverting input terminal of comparator AC1.

When the monitor output from the terminal ANM of the light receiving unit FMD reaches the level of the low voltage source E2 or E3, the output STP1 of the comparator AC1 is inverted to "High",
A transfer pulse is output from the terminal φT of the control circuit COC. By this pulse, the accumulated charge in the charge storage section corresponding to the amount of light received in each light receiving section is transferred to the transfer gate, and the accumulated charge signal is sequentially sent from the terminal ANS to the control circuit COC based on the transfer pulses φ1, φ2, and φ3. Sent. In the control circuit COC, the terminal
The signals sent from the ANS are sequentially converted from A to D,
Every time one AD conversion is completed, a pulse is output to the terminal ADE, and the AD converted data is output to the output terminal ADD.

Furthermore, if a transfer pulse is not output from the terminal φT even after a certain period of time has elapsed since the start of charge accumulation, this means that the brightness of the subject is low, and in this case a pulse is output from the terminal O2, and this pulse When input, the control circuit COC outputs comparator AC1
Transfer pulse φT is output regardless of the output of .

When performing preliminary irradiation using the electronic flash device, the terminal O1 becomes "High", and the voltage from the constant voltage source E3 is input to the non-inverting terminal of the comparator AC1. The output potential of this constant voltage source is higher than the output potential of the constant voltage source E2. Therefore, the transfer pulse φT is output when the amount of charge accumulated by the monitor section is smaller than that in the case where preliminary irradiation is not performed. This is because when performing preliminary irradiation with flash light, the intensity of the flash light changes rapidly, which may cause the charge storage section to overflow due to a delay in the response of the circuit, making it impossible to measure the correct light intensity distribution. This is to prevent this from happening.

As mentioned above, when the terminal O3 of the microcomputer MCO1 becomes "High" to start charge accumulation, a pulse is output from the one-shot circuit OS1, and this pulse is output via the AND circuit AN1 and then via the terminals JB1 and JF1. A light emission start signal is sent to the electronic flash device. Even when preliminary irradiation is performed, if the transfer pulse φT is not output even after a certain period of time has elapsed, a pulse is output from the terminal O2 to forcibly output the transfer pulse, and the charge accumulation operation is stopped. Incidentally, the fixed time period that limits the accumulation time is shorter than that in the case where preliminary irradiation is not performed. This is because the flash light emission time is short and there is no need to keep the integration time long.

When the microcomputer MCO2 reads data from the electronic flash device FLC, this data includes a signal indicating whether preliminary irradiation is possible. Therefore, when a signal indicating that preliminary irradiation is possible is input, the microcomputer MCO2 sets the terminal O16 to "High". The microcomputer MCO1 determines that operation in the pre-irradiation mode is possible if the terminal i2 is “High”, and that it is not possible to operate in the pre-irradiation mode if it is “Low”. Discern.

MDR is a circuit that drives the focus adjustment motor MO, and when the focus detection result is the front focus and the lens needs to retract, the terminal O4 of the microcomputer MCO1 is used, and when the lens needs to be retracted, the terminal O5 is used. becomes “High”. The rotation of the motor MO is transmitted to the lens side LE via the lens drive unit LD, and the focus of the lens is adjusted. In addition, the drive amount of the lens drive unit LD is converted into a pulse signal by the encoder ENC, and this pulse signal is
It is input to the clock input terminal CPI of MCO1 and the drive amount is counted. Also, the encoder ENC
The pulses are input to the motor drive circuit MDR and used as a reference signal to drive the motor MO so that the lens drive speed is constant.

FDP is a display section that displays the focus adjustment status.
According to the data from the microcontroller's output terminal OP1,
Displays front focus status, focus status, rear focus status, and focus adjustment failure warning.

The switch SMB shown in the upper left corner of the figure is the main switch, and BB is the power battery.
From this power supply battery BB, the microcomputer MCO1,
Power is supplied directly to MCO2. switch S1
is a photometry switch that is closed when the release button (not shown) is pressed in the first step, and when this switch S1 is closed, inverter IN3 and AND circuit AN
3. An interrupt signal is input to the interrupt terminal it of the microcomputer MCO2 via the OR circuit OR4, and the terminal O12 is set to "High", making the transistor BT1 conductive via the inverter IN6, and inverting the inverter IN3 via the power line (+V). ~IN6, AND circuit AN2,
AN3, OR circuit OR4, microcomputer MCO1,
Start supplying power to circuits other than MCO2. and,
The power-on reset circuit is activated based on this start of power supply.
A reset pulse is output from PO1, and the circuit to which power is supplied from the power line (+V) is reset. Further, when the terminal O12 becomes "High", the AND circuit AN3 becomes disabled, AN2 becomes active, and no interrupt signal from the switch S1 is input.

Switch S2 is a release switch that is closed when the release button is pressed in the second step, and S4 is a reset switch that is opened when the exposure control operation is completed and closed when the exposure control mechanism (not shown) is fully charged. It is. Therefore, when the exposure control mechanism is completely charged and the reset switch S4 is closed and the relay switch S2 is closed, an interrupt signal is input to the terminal it via the AND circuit AN2 and the OR circuit OR4. Ru.

The EDO in the center of the figure is a block that outputs the set exposure control data, and the setting data is sequentially sent to the terminal IP based on the read signal from the terminal OP13.
Read from 10. LMC is a photometric circuit for exposure, and the output of the photometric circuit LMC is input to an analog input terminal ANI for A-D conversion. Also, as a reference voltage for the D-A converter of the microcomputer MCO2,
The reference voltage in the photometric circuit LMC is input to the terminal VRI.

EXD is the display circuit that displays the exposure control value.
The exposure control value is displayed based on the display data from OP14. EXC is the exposure control circuit and the terminal OP
The aperture and exposure time are controlled based on signals from 15. In addition, the terminal TIE becomes "High" from the time of shutter release until a certain period of time has elapsed after the trailing curtain starts running, enabling integral operation for controlling the amount of flash light emission during shooting.

LEB is an interface circuit for reading data from the lens side circuit LEC. As described above, when the transistor BT1 becomes conductive, power is supplied from the power supply line (+V) to the lens side circuit LEC via the terminals JB11 and JL1. and,
When the terminal O15 of the microcomputer MCO2 becomes "High", the interface circuit LEB becomes operable, and further, the terminals JB12 and JL2 become "High", so that the lens side circuit LEC also becomes operable. The circuit LEC on the lens side includes a ROM that fixedly stores data for exposure control and automatic focus adjustment specific to this conversion lens at multiple addresses, and the address of this ROM is input via terminals JB13 and JL3. address designating means for sequentially specifying an address based on the output of a code plate corresponding to the clock pulse and focal length of the lens if the lens is a zoom lens;
The data output in parallel from terminal JB13,
Parallel-to-serial conversion means is provided for sequentially outputting one bit at a time via terminals JL4 and JB14 based on a clock pulse input via JL3. The data fixedly stored in the ROM includes check data that is common to all conversion lenses to confirm installation, maximum aperture value data, and maximum aperture value (aperture value when the aperture is at its minimum). value) data, open photometry error data,
Data includes focal length data, and data on the amount of change in aperture according to the focal length setting for a zoom lens. Furthermore, a conversion coefficient KD for converting the amount of defocus detected by the focus detection device into the amount of lens drive,
To correct the difference in focus position between near-infrared light and visible light (difference in defocus amount) due to near-infrared light irradiation to prevent the subject from feeling dazzling during preliminary flash illumination. Data IRD (for correcting the amount of defocus measured using near-infrared light to the amount of defocus measured using visible light), when the driving direction of the lens is changed from one direction to the other, the drive axis on the camera side and There is an extra drive amount, ie, backlash data BLD, etc. when the drive shaft needs to be driven extra due to looseness in the fitting with the driven shaft on the lens side.

Eight clock pulses are output from terminal SCP of microcomputer MCO2, and the circuit on the lens side
In the LEC, the ROM address is updated every time eight clock pulses are input, and the data fixedly stored at the specified address is output in series based on the clock pulse, and the microcontroller
It is read sequentially from the serial input/output terminal SIO of MCO2.

FLB is an electronic flash device control circuit, and FLC is a circuit within the electronic flash device. A specific example of the circuit FLC in the electronic flash device is shown in FIG. 3, and the operation of using the electronic flash device will be explained below in conjunction with FIG. In FIG. 3, BF is the power battery for the electronic flash device, and SMF is the main switch.
DD is a booster circuit, and a high voltage terminal on the secondary winding side of the booster circuit DD is connected to a main capacitor C2 via a diode D1, and the main capacitor C2 is charged with the voltage of the high voltage terminal. Also, 2
The low voltage terminal of the next winding is connected to capacitor C1 via diode D2, and capacitor C1 is charged with its output voltage. When the main switch SMF is closed, transistors BT2 and BT3 become conductive, and power is supplied to the power supply line VF via the boosted output from the voltage stabilizing circuit CV or the output transistor BT3 of the power supply battery BF via the diode D3.
Power is supplied from this power supply line VF to all circuits whose power supply paths are not shown in FIG. Furthermore, when power supply from the power supply line VF starts, a reset signal is output from the power-on reset circuit PO2, and a reset operation is performed on the digital circuit section. The switch SOF is a switch that opens and closes in the same phase in conjunction with the main switch SMF. The resistors R1 to R4 are resistors that divide the charging voltage of the main capacitor C2, and VC is a constant voltage source. When the potential at the connection point between resistors R1 and R2 exceeds the potential of the constant voltage source VC, the comparator
The output of AC21 becomes "High", and when this signal becomes "High", the capacitor C2 is charged to the minimum voltage required for the xenon tube XE1 to emit light, and the light emission start signal is input. and starts the xenon tube XE2 to emit light. When the potential at the contact point between the resistors R2 and R3 exceeds the output potential of the constant voltage source VC, the output of the comparator AC22 becomes "High". In this case, the voltage of the main capacitor C2 has been charged to the voltage required for the xenon tube Charging completion display is performed by . When the potential at the connection point between the resistors R3 and R4 exceeds the output potential of the constant voltage source VC, the output of the comparator AC23 becomes "High". At this time, the xenon tube XE2 for photography emits only the nominal value, and the xenon tube XE1 for preliminary illumination also emits light.
This signal indicates that the main capacitor C2 has been charged to the value required to emit light twice by a predetermined amount, and this signal is sent to the camera side as a preliminary irradiation enable signal. Note that the switch SS is a switch that can be changed manually, and if this switch SS is connected to the terminal EN, the preliminary irradiation enable signal is sent to the camera side, but if it is connected to the terminal DEN, the signal is sent to the terminal PCH.
The input to is always "Low" and the preliminary irradiation enable signal is not sent to the camera side, so the camera does not enter the preliminary irradiation mode, and the output of the OR circuit OR20 remains "Low", so no light is emitted.

TR1 and TR2 are xenon tubes XE1 and XE2 respectively
Trigger circuit that triggers thyristors SC1 and SC2 to conduct, ST1 and ST2 respectively turn off thyristors SC1 and SC2 and connect xenon tubes XE1 and
This is a stop circuit that stops the XE2 from emitting light.
In addition, the xenon tube XE1 is used for preliminary irradiation, and a filter FLT is installed at the light emission position of this xenon tube XE1 to transmit near-infrared light and cut out visible light with a shorter wavelength than near-infrared light. , so that the subject does not feel dazzled when performing preliminary illumination.

In Figure 2, terminal O13 of microcomputer MCO2
When becomes “High”, data can be exchanged between the camera and the electronic flash device. When a pulse with a width of 50 μsec is output from the terminal O14 of the microcomputer MCO2, this pulse is sent to the flash device via the terminals JB2 and JF2. With this pulse, the mode discrimination circuit FMS shown in FIG. 3 discriminates that the mode is for transferring data from the flash to the camera, and sets the terminal DOM to "High". Then, the data output circuit DOU of FIG. 3 becomes operational. Then, when a clock pulse is output from the clock pulse output terminal SCP of the microcomputer MCO2, this clock pulse is inputted to the terminal SCP of the data output circuit DOU in Fig. 3 via the terminals JB2 and JF2, and based on this clock pulse, the electronic flash device A power supply signal indicating that power is being supplied at , a signal to terminal PCH indicating that the electronic flash device is ready for preliminary irradiation, a charge completion signal to terminal CHC, and dimming operation are performed. A signal to terminal FDC indicating whether the
It is sent to the camera side via terminals JF3 and JB3.
Other data sent includes, for example, the maximum and minimum amount of light emitted by the flash, the aperture value set by the flash, the bounce state, and whether or not it is a multi-flash flash. When the data transfer is completed, a pulse is output from terminal r2, and the OR circuit OR
12, the mode discrimination circuit FMS enters an initial state, and its terminal DOM becomes "Low".

Next, 100μsec from terminal O14 of microcomputer MCO2.
When the width pulse is output, the mode discrimination circuit FMS
sets the terminal DIM to “High”. Then, the data input circuit DIN becomes active. Then, the microcomputer MCO2 of the camera body outputs a clock pulse from the terminal SCP, and based on this clock pulse, the aperture value for flash photography is set from the terminal SIO.
Outputs data such as exposure time, film sensitivity, and shooting distance. This data is read into the data input circuit DIN via terminals JB3 and JF3. The display circuit DSP displays the data based on the read data.
is displayed.

When starting the exposure control operation, the microcomputer
A pulse with a width of 150 μsec is output from terminal O14 of MCO2. Then, the mode discrimination circuit FMS outputs the terminal FLM.
Set to “High”. This allows the light emission control circuit to
The FLC becomes active and light emission control is performed.
When the X contact SX of the camera is closed at the same time as the front curtain of the focus shutter of the camera completes travel, a light emission start signal is inputted to the terminal STA from the terminals JB4 and JF4, and a light emission start signal is outputted from the terminal α1. At the same time, terminal α3 changes from “High” to “Low”.
This signal is inverted and sent to the camera side via terminals JF3 and JB3. On the camera side, terminal JB3
When becomes “Low”, the photometric integration circuit (not shown) in the circuit FLB integrates the amount of light reflected from the subject illuminated by the flash light and passed through the aperture (not shown) of the photographing lens. When the integrated amount reaches an analog value corresponding to the film sensitivity from the analog output terminal ANO, a pulse for stopping light emission is output to the terminal JB2. This pulse is at terminal JF2
It is input to the terminal STP of the light emission control circuit FLC via. Then, a light emission stop signal is output from the terminal α2, and the light emission of the xenon tube XE2 is stopped. Also,
The light emission stop signal from terminal α2 is also sent to the display circuit FDP, and when the exposure control operation is completed, the X contact SX
is opened, but based on this signal, the X contact SX
Terminal df becomes “High” for a certain period of time after opening,
During this time, it is displayed that the dimming operation has been performed.
Furthermore, this signal is also sent to the camera side via the data output circuit DOU. Furthermore, when the X contact SX is opened, a pulse is output from the terminal r3, the mode discrimination circuit FMS is reset via the OR circuit OR12, and the terminal FLM becomes "Low".

In the preliminary irradiation mode, when O1 of the microcomputer MCO1 is in the "High" state, a "High" signal is output from the terminal O3 to start accumulation.
A pulse is output from the one-shot circuit OS1, and this pulse is output from the AND circuit AN1.
This pulse is input to the AND circuit AN20 in FIG. 3 via terminals JB1 and JF1. At this time, D
The output of flip-flop DF21 is “High”
and the output of comparator AC23 becomes “High”
and the output of OR circuit RO20 is “High”
Therefore, the pulse input to the AND circuit AN20 is output from the AND circuit AN20. This pulse is sent to the trigger circuit TR1 and the xenon tube
Preliminary irradiation with XE1 begins. And the pulse from the AND circuit AN20 is a flip-flop
Since RF20 is set, the reset state of counter CO6 is released and counter CO6 starts counting. Then, when a certain period of time has elapsed since the start of counting, the terminal f1 of the decoder DE6 becomes "High" and a pulse is output from the one-shot circuit OS22. This pulse is the light emission stop circuit
It is sent to ST1 and preliminary irradiation by xenon tube XE1 is stopped. Also, the terminal f1 of the decoder DE6
becomes “High”, flip-flop RF20 is reset via OR circuit OR22,
The counter CO6 is in the reset state, and the terminal f1
becomes “Low”. In addition, the output pulse of the AND circuit AN20 is sent to the clock pulse input terminal of the D flip-flop DF20, and the output pulse is sent to the clock pulse input terminal of the D flip-flop DF20.
The "High" output of AC23 is latched, and the Q output of D flip-flop DF20 becomes "High".

When the second pulse is output from the AND circuit AN20, the charging voltage of the main capacitor C2 decreases and the output of the comparator AC23 becomes “Low”.
Even if it is, the Q output of the D flip-flop DF20 is "High" at the time of the first light emission, so the output of the OR circuit OR20 is "High", and the pulse is output from the AND circuit AN20. Output. The pulse causes the same light emitting operation as described above. Furthermore, this pulse causes the Q output of the D flip-flop DF21 to become "High". Then, one-shot circuit OS2
A pulse is output from 0, and at the fall of this pulse, a pulse is output from the one-shot circuit OS21, and the D flip-flops DF20 and DF21 are reset to return to their initial states.

FIG. 4 is a flow chart showing the operation of the microcomputer MCO2 shown in FIG. The operation of the system shown in FIG. 2 will be explained below based on this flowchart. When the photometric switch S1 is closed and an interrupt signal is input to the terminal it, the microcomputer MCO2 starts operating. First, it is determined whether the flag LMF is "1". This flag LMF is set to "1" if the exposure control data has been calculated, but when the photometry switch S1 is closed and the interrupt signal is input, the calculation has not been performed yet, so the flag LMF is set to "1". is "0", and the process moves to step S2. In step S2, the terminal O12 is set to "High" to turn on the transistor BT1 and start supplying power via the power supply line (+V). Next, serial input/output operations are performed multiple times to acquire multiple data from the lens circuit LEC, and the conversion coefficient KD necessary for automatic focus adjustment is obtained.
is output to terminal OP10, data IRD for correcting the focusing position of near-infrared light and visible light is output to terminal OP11, and backlash data BLD is output to terminal OP12. ，
Send to IP3 and IP4. Then, the output terminal O10 is set to "High". This signal is input to the interrupt terminal it2 of the microcomputer MCO1, and when this signal is output, the microcomputer MCO1 starts operating.

In step S6, data from the block EDO that outputs setting data is taken in, and then serial input/output operation is performed to take in data from the flash in series. Then, it is determined in step S8 whether or not a signal enabling preliminary irradiation is input, and if it is input, the terminal O16 is set to "High".
If no input has been made, the terminal O16 is set to "Low" and the process moves to step S11.

In step S11, the terminal O18 is set to "High". This signal is the input terminal i5 of the microcomputer MCO1.
When read by the microcomputer MCO1, the microcomputer
The MCO2 determines that the A-D conversion operation is being performed, causes the xenon tube to emit light, and does not proceed to the focus detection operation. Next, the microcomputer
The MCO2 determines whether or not the input terminal i15 is set to "High", and if it is set to "High", this terminal i15 becomes "Low". The output terminal O8 of the microcomputer MCO1 is connected to this input terminal i15, and this terminal is set to "High" while the xenon tube is emitting light and a focus detection operation is being performed. Therefore, the microcomputer MCO2
is A-D while this input terminal i15 is “High”
No conversion operation is performed. terminal i
15 is "Low" or becomes "Low", next, the photometry output from the photometry circuit LMC is converted from A to D, and the terminal O18 is set to "Low".
- No longer outputs a signal indicating that D conversion is in progress. All the data necessary for exposure calculation has now been imported.

Next, in steps S15 and S16, exposure calculations for constant light and flash light are performed. And the flag
Determine whether RLF is “1”. RLF is “1”
If so, it means that the process has moved to this step despite the interruption caused by release switch S2.
The process moves to step S33 for release, which will be described later.
On the other hand, if the flag RLF is "0", it means that this step was entered by an interruption by the photometry switch S1, and the step moves to step S18 and the flag is set to "0".
Step by setting LMF to “1” and enabling interrupts.
Move to 20. In step S20, serial input/output operations are performed to send data to the electronic flash device FLC.
In step S21, it is determined whether or not the power supply signal has been read from the electronic flash device. If the power supply signal has been read, the data for flash light photography is displayed on the display; if the power supply signal has not been read, the data for constant light photography is displayed on the display.
Send to EXD and proceed to step S40. Then, in step S40, it is determined whether or not the terminal i12 is set to "High" while the photometric switch S1 remains closed. If it is set to "High", the process returns to step S3 and the same operation as described above is repeated. On the other hand, if it is determined in step S40 that the terminal i12 is set to "Low", the terminal O10 is set to "Low".
to stop the autofocus operation and set the flag
LMF is set to "0", terminal O12 is set to "Low", the transistor is turned off, and the power supply line (+
The power supply from V) is stopped, the display on the display section EXD is turned off, and the microcomputer MCO2 stops operating.

When an interrupt signal is input with the exposure control data calculated, the process moves to step S31 and terminal O1 is input.
0, O16 is set to "Low" to output a signal to stop the automatic focus adjustment operation. Then, the flag RLF is set to "1" to indicate that the interrupt by the release switch S2 has been performed, and the process moves to step S33. In step S33, it is determined whether the input terminal i11 is "High", and if it is "High", the process moves to step S3 for exposure calculation, and the input terminal i11 is "Low".
If so, the process moves to step S34 for exposure control. This input terminal i11 is connected to the output terminal O7 of the microcomputer MCO1, and this terminal outputs the following signals. First, during an automatic focus adjustment operation that does not use preliminary illumination, a "High" signal is output until the movement of the photographic lens completely stops, and a "Low" signal is output when the movement of the photographic lens completely stops. Therefore, since the microcomputer MCO2 does not shift to the exposure control operation while the terminal i11 is "High", it is possible to prevent malfunctions such as when the exposure control operation is executed while the photographing lens is moving. On the other hand, when performing an automatic focus adjustment operation using preliminary irradiation, it is necessary to wait for a certain period of time (for example, 200 m
sec), even if the automatic focus adjustment operation is stopped or a signal to stop the automatic focus adjustment operation is input from the microcomputer MCO2, a "High" signal is output. Therefore, the exposure control operation is not performed for at least a certain period of time after the preliminary irradiation, and the exposure control calculation operation is repeated. This is the A-D of the output of the photometric circuit LMC.
This prevents exposure from being controlled with an exposure control value based on incorrect A-D conversion data due to conversion and preliminary irradiation being executed at the same time. Furthermore, even if the preliminary flash light is near-infrared light, the subject may feel dazzling.
Eyelids may close. However, after a certain period of time, the eyelids will open and normal facial expressions can be photographed.

When the terminal i11 becomes “Low”, step S34
to determine whether or not a power supply signal is input from the flash, and if so, sends the exposure control data for flash light to the control unit EXC, and if no power supply signal is input, controls the exposure control data for constant light. Send control data to control unit EXC. Then, the exposure control operation is started. The microcomputer MCO2 then waits until the exposure control operation is completed, the reset switch S4 is released, and the terminal i10 becomes "Low". Then, when the terminal i10 becomes "Low", it is determined in step S40 whether the photometry switch S1 is closed or not. If it is closed, the process moves to the aforementioned step S3 and data acquisition, calculation and display operations are repeated. If the photometry switch S1 is not closed, the microcomputer MCO2 stops operating after proceeding to step S41 and performing the same operations as described above.

5-1 to 5-3 are flowcharts showing operations for automatic focus adjustment by the microcomputer MCO1. The operation of the circuit of FIG. 2 for automatic focus adjustment will be described below with reference to FIGS. 5-1 to 5-3.
When the terminal O10 of the microcomputer MCO2 becomes “High” to start the automatic focus adjustment operation, the terminal it
An interrupt signal is input to 2, and the operation of the microcomputer MCO1 starts. First, in step #1, the microcomputer MCO2 confirms that automatic focus adjustment is being performed.
The terminal O7 is set to "High" in order to transmit the signal. Then, interrupts by the terminal it1 and the counter are enabled, and interrupts by the timer are disabled, and the terminal O3
By setting “High” to the control circuit COC,
Start charge accumulation operation by CDC and FMD.
In the following description, counters and registers whose symbols are not enclosed in brackets are internal to the microcomputer.

In step #4, in the microcomputer MCO1,
Counter that counts external or internal clock
Set the contents of COR to register ECR1. As will be described later, this data is necessary for calculating the amount of movement of the lens during focus detection in order to perform focus detection while moving the photographic lens, and is not necessary during the first measurement. In step #5, it is determined whether the flag FLF is "1".
This flag is set to "1" when preliminary irradiation by flash is performed, and is set to "0" when measurement is performed using only stationary light. 1st
At the time of the second measurement, preliminary irradiation is not necessarily performed and the flag FLF is set to "0", and the process moves to step #6.

In step #6, timer register TIR1
Set a fixed value Ka to . This register TIR1 is a register that counts time using software.In addition to this, there is a timer counter TIC that counts the internal clock independently of the software.When the contents of this counter TIC become "0", a timer interrupt is generated. . And register ECR4 contains counter COR.
and set the fixed value K1 in the timer register TIR2. This register TIR2 is also TIR
Like 1, this is a register that counts time using software. Then, it repeats the operation of subtracting "1" from the contents of the timer register TIR2 and determining whether the contents of the register TIR2 has become "0" or not, and waits for a certain period of time. After a certain period of time has passed, input terminal i3 becomes “Low” in step #11.
If it is "Low", as mentioned above, the signal to stop the automatic focus adjustment operation has been input from the microcomputer MCO2, so the automatic focus adjustment operation starts from step #209. Perform an action to stop it. On the other hand, terminal i3
If is “High”, flag in step #12
Determine whether FPF is “1”. this flag
FPF is "1" when the motor MO is stopped, as in the first measurement. Therefore, if the flag FPF is "1" and the motor MO is stopped, the process moves from step #12 to step #15, and in step #6, "1" is read from register TIR1 to which the fixed value Ka is set. Subtract and TIR
Determine whether the content of 1 has become “0”,
If it is not "0", the process returns to step #7 and repeats the same operation. While this operation is repeated, when the output of the comparator AC1 in Fig. 2 is inverted to "High", the terminal φT of the control circuit COC
A transfer pulse is output from , this pulse is input to the interrupt terminal it1, and the microcomputer MCO1 starts its operation from step #24. Furthermore, if it is determined in step #16 that the contents of register TIR1 have become "0", then in step #21 the terminal O2 is
It outputs a pulse to forcibly stop the storage operation as described above, sets the flag TOF to "1", completes the operation, and waits for an interrupt signal to the terminal it1. After starting the accumulation operation in step #3,
The time until it is determined in step #16 that the contents of the register TIR1 are "0" is a fixed time, and the accumulation time is designed not to become longer than this.

Flag when motor MO is driven
The FPF has become "0" and the process moves from step #12 to step #13. In step #13, the contents of counter COR are transferred to register ECR.
Set to 5. And in step #14, #7
The contents of the register ECR4, in which the contents of the counter COR were set in step , are compared with the contents of this register ECR5. A certain period of time has elapsed between steps #7 and #13, and if the lens has not moved during this time, no clock pulse is input from the encoder ENC and ECR4=ECR5. Therefore, even if the motor MO is driven, the lens is at the end position (infinity position or closest position).
This means that the lens has stopped moving. In this case, the flag LSF (“0” during normal focusing operation, a low contrast signal indicating that the contrast of the subject image is low) is output.
When scanning a lens position that is not low contrast, the content is "1"), and if it is "1", it means that scanning is in progress at low contrast, and the process moves to step #158, and if it is "0", it is "1". Normal focusing operation is in progress and the process moves to step #63.

If the flag FLF is "1" in step #5, it is a mode for preliminary flash light irradiation, and in this case, the process moves to step #17. At this time, set the fixed value Kf in register TIR1, subtract "1" from register TIR1, determine whether terminal i3 is "Low", and if it is "High",
Determine whether the content of TIR1 is “0”. If it is not "0", the operation returns to step #18 and is repeated, and when the content of TIR1 becomes "0" in step #20, the process moves to step #21 and the above-described operation is performed. In this preliminary irradiation mode, the storage time limit is much shorter than in the constant light mode. This is configured this way for the following reasons. Light in the near-infrared region is used for the preliminary illumination light so that the human subject will not feel dazzled. On the other hand, when preliminary irradiation is not performed, measurement is performed using constant light, which is generally white light. Therefore, when measuring a mixture of both lights, it is not possible to correct the influence of chromatic aberration on the amount of defocus unless the mixing ratio is known. Therefore, in the preliminary irradiation mode, in order to prevent the steady light component from being measured as much as possible, the maximum accumulation time is set to be approximately equal to the light emission time of the xenon tube XE1, making it possible to accurately correct chromatic aberration. ing. Furthermore, in the preliminary irradiation mode, the motor MO is not driven during measurement, so no end detection operation is performed to determine whether the lens has reached the end.

When a transfer pulse is output from the terminal φT of the control circuit COC and an interrupt signal is input to the terminal it1, #24
The operation starts from step 1. In step #24, the terminal O8 is set to "Low" to enable A-D conversion by the microcomputer MCO2. Then, enable an interrupt to terminal it1, set terminal O3 to “Low”, and register the contents of counter COR.
Import into ECR2. This is data for correcting errors caused by lens movement when the lens is moved during measurement. Next, data obtained by A-D converting the amount of light received by each light-receiving section output from the control circuit COC is sequentially imported, and A-D conversion corresponding to all light-receiving sections is performed.
Once the converted data has been imported, the process moves to step #29. At step #29, flag FLF is “1”
If it is "1", interrupt by timer (the function will be explained later) is enabled and #32
Move on to the next step. If it is not "1", it is determined whether the flag TOF is "1". flag
TOF becomes "1" in step #22 when the accumulation time reaches the limited time. Therefore, when FLF is "0" and TOF is "1", the brightness is low in the constant light mode, and the flag LLF is set to "1" in step #31. Otherwise, the flag LLF is set to "1" in step #32. Set it to “0”,
In #33, the flag TOF is set to "0". #34
Now, the degree of correlation between the two rows of light receiving sections is determined based on the output from the light receiving section FMD, and from this degree of correlation, the amount of defocus and the direction of defocus are calculated. This operation is performed, for example, as proposed in US Pat. No. 4,333,007. This calculated amount of defocus is |LD|, and the direction of the defocus is LD>
When it is 0, it is the front pin, and when LD<0, it is the rear pin.

In step #35, it is determined whether the flag FLF is "1" or not, and when FLF is "0" and measurement is performed using steady light (visible light), the calculated data is
LD is set to the correct value LDt, FLF is “1”
If so, it is the preliminary irradiation mode, and at this time, measurement is being performed with near-infrared light, so only the difference between the focused position of visible light and the focused position of near-infrared light, that is, IRD, is corrected. In order to do this, the calculation LD-IRD is performed and this calculated value is used as the correct defocus amount LDt. The data IRD uses the data sent from the lens as is, but for example, the lens stores correction data for a specific wavelength, obtains data on the wavelength of the light source for preliminary irradiation, and then The correction data may be converted into data corresponding to , and the defocus amount may be corrected using the converted correction data.

At #38, it is determined whether the terminal i3 is "Low", and if it is "Low", the process moves to step #209 as described above. On the other hand, terminal i3 is “High”
If so, then it is determined whether the measured data has low contrast. This low contrast determination is performed by calculating the sum of the absolute values of the differences in output between adjacent light receiving parts in each light receiving part of the light receiving element array.
When this sum is less than or equal to a predetermined value, it may be determined that the contrast is low. Note that in the case of low contrast, the amount of defocus is calculated by comparing the state of the light distribution of the two rows of light receiving elements, so the calculated amount of defocus has poor reliability. When low contrast is determined, the process moves to step #110 and an operation for low contrast is performed. If it is determined in step #39 that the contrast is not low, a flag is set in step #40.
Determine whether LCF1 is “1”. and,
If the flag LCF1 is "1", the previous measured value is low contrast, and in this case, it is determined in step #41 whether the flag FLF is "1". If the flag FLF is "1", then it is #1 because preliminary irradiation by flash is being performed in this measurement.
Perform the operations from step 70. On the other hand, if the flag FLF is "0", it means that the previous measurement had low contrast and the current measurement had sufficient contrast without performing preliminary irradiation. At this time, the flags LCF1, LCF2, SEF1,
Set SEF2 and LSF to “0” and flag TIF to “1”
If it is not "1", the operation from #50 is performed. In this case, the measured value is low contrast, and during the measurement while moving the lens until a measured value that is not low contrast is obtained (hereinafter referred to as low contrast scan mode), a measured value that is not low contrast is obtained. In this case, the operation shifts to the operation of moving the lens based on the amount of defocus from step #50. Also, the flag is set in step #43.
If TIF is "1", the lens scans the entire area in low contrast scan mode, and during this period no measurement value other than low contrast is obtained, and the lens is stopped for a certain period of time and measurements are repeated (hereinafter referred to as low contrast scan mode). (referred to as stop mode). In this case, counter COR is in a mode (timer mode) that counts the internal clock of microcomputer MCO1.
, so set the event count mode (a mode that counts clock pulses from the encoder ENC), set the flag FPF to "1" and TIF to "0", and move to step #50.
The process moves to step 3 and the same operation as in the case where the first measured value is not low contrast is performed.

When flag LCF1 is “0” in step #40, or when flag LCF1 is set to “0” in step #43 mentioned above,
When TIF is "0" or from step #46, the process moves to step #50. In step #50, the lens movement amount ND is calculated by multiplying the defocus amount LDt by the conversion coefficient KD. Next, LID is the data in the range that can be considered to be in focus, and it is multiplied by the conversion coefficient KD to determine the amount of movement of the lens in the in-focus area.
Calculate IFD. In step #52, flag
It is determined whether the FPF is "1" or not, and if it is "1", the process moves to step #75, and if it is "0", the process moves to step #53. Therefore, if the motor MO is being driven, the process moves to step #53, and if the motor MO is not being driven, the process moves to step #75.

In step #53, charge is accumulated by calculating the difference τ between the content outputs of register ECR1, which captures the contents of counter COR at the start of charge accumulation in the light receiving unit FMD, and register ECR2, which captures the contents of counter COR at the end of accumulation. Calculate the amount of movement τ of the lens inside. Then, set the contents of counter COR at this point in register ECR3 and register ECR2.
The difference t between the contents of ECR3 and ECR3 is calculated, and the amount of movement t of the lens during calculation of the amount of defocus is calculated. The calculated amount of defocus is assumed to be a value based on the measured value at the middle of the lens movement during the accumulation time, and the lens movement amount ND calculated is the amount that the lens moves by τ/2+t from the point of measurement. Therefore, in step #56, |ND|−(τ/
2+t)=NDc is calculated to correct the movement amount. In step #57, this corrected movement amount data |NDc| is compared with the data of the focus area IFD, and if |NDc|≦IFD, it is in the focus area, and step #58 is performed. Then, terminals O4 and O5 are set to "Low" to stop the motor MO, flags IFF and FPF are set to "1", and the process returns to step #2 to perform focus detection for confirmation.

If it is determined in step #57 that |NDc|>IFD, the process moves to step #61 and the contents of counter COR are set in register ECR3, and the contents and the counter at step #27 are set.
The COR contents are compared with the contents of the set register ECR2. When it is determined that ECR2=ECR3, the lens has reached the end, and in step #63, terminals O4 and O5 are set to "Low" to stop the rotation of the motor MO and flags ENF and FPF are set to "1". ”, return to step #2, and perform the measurement again.

If it is determined in step #62 that ECR2≠ECR3, the correction data is stored in step #66.
Determine whether NDc has become a negative value.
If the value is negative, the calculated amount of movement |
The correction amount (τ/2+t) is larger than ND|, which means that the lens has passed the in-focus position. Therefore, in this case, proceed to step #71, set the terminals O4 and O5 to "Low", stop the rotation of the motor MO, and set the flag SCF,
Set the FPF to "1" and return to step #2 to perform focus detection for confirmation.

If it is determined in step #66 that NDc>0, then in step #67 it is determined whether the driving direction of the lens is the retraction direction (ND>0). And if ND>0, #68, ND<0
(feeding direction), it is determined in step #69 whether the flag SIF is "1". This flag SIF is set to "1" if the moving direction of the lens at this point is in the retracting direction, and is set to "0" if the moving direction of the lens is in the extending direction. Therefore, when the flag SIF is "0" in step #68 or "1" in step #69, the direction of lens movement at this point and the calculated direction of lens movement are reversed. Therefore, proceed to step #71 mentioned above, stop the motor MO, and set the flag.
Set SCF and FPF to "1" and return to step #2 to perform focus detection for confirmation. On the other hand, if the direction is not reversed, the data NDc calculated in step #56 is set in the counter COR, and the process returns to step #2 to perform the next measurement.

When the flag FPF is "1" in step #52, the motor MO is stopped and focus detection is performed without preliminary irradiation. In this case, first determine whether |ND|≦IFD, and if |ND|≦IFD, display the focus in step #76, and return to step #2 to select the next focus. Performs detection operation. On the other hand, |ND|>
If it is IFD, proceed to step #80 in Figure 5-2. In steps #80 to #82, the flag
Determine whether IFF, SCF, and ENF are "1". These flags are set to "1" when the moving lens is temporarily stopped and focus detection is performed for confirmation as described above, and if any of the flags is set to "1", Move to step #84. In steps #84 to #86, as in steps #67 to #69 described above, it is determined whether the direction in which the lens was previously driven matches the direction obtained by the current focus detection. Determine and if it is reversed, #87,
Invert the flag SIF in step #88, and
In step 1, the counter calculates the value obtained by adding the backlash data BLD to the data of the movement amount |ND|
Set it to COR and move on to step #96.
On the other hand, if the directions match, it is determined in step #89 whether the flag ENF is "1".
If the flag ENF is "1", the lens has reached the end as described above, and in this case, the lens cannot be driven in the calculated direction, so a warning is displayed. #2
Return to step 1 and perform the next focus detection operation. On the other hand, if the flag ENF is "0", the movement amount data |ND| is set in the counter COR in step #95, and the process proceeds to step #96.

When the flags ENF, SCF, and IFF are all "0", it is the first focus detection operation, and the moving direction is determined in step #92, and if ND>0, the flag is
Set SIF to “1”, set SIF to “0” if ND<0,
At step #95, the movement amount data |ND| is set in the counter COR, and the process moves to step #96.

In step #96, the mode is set to event count mode, in which the data set in the counter COR is subtracted by the clock pulse input from the encoder ENC, and then the terminal 04 or 05 is set to "High" depending on the direction of movement. as motor
Start MO rotation, flags FPF, IFF,
Set SCF and ENF to “0” and display the front pin or rear pin according to the contents of the flag SIF #2
The process returns to step 1 and the next focus detection operation is performed.

If it is determined in step #39 that the measurement result is low contrast, the process moves to step #110. At step #110, the flag
It is determined whether the FPF is "1" or not, and if it is "1", this is the first measurement and the process moves to step #111. In step #111, it is determined whether the flag LLF is "1". As explained in steps #29 to #33, this flag LLF is a flag that is "1" when the subject brightness is low, and if this flag LLF is "1", #112
If it is "0", the process moves to step #121.

At step #112, terminal i2 becomes “High”
Determine whether it is. and terminal i
If flag SEF2 is "Low", it is determined in step #113 whether flag SEF2 is "1". This flag SEF2, which will be described later, is a flag that becomes "1" when the lens travels over the entire area in the low-contrast scan mode. Therefore, if the flag is set to "1", the process moves to step #144 to enter the low contrast stop mode, which will be described later. On the other hand, if the flag SEF2 has become "0", the process shifts to the low control scan mode from #121.

If it is determined in step #112 that the terminal i2 is "High", it means that light emission for preliminary irradiation is possible at this time, and the operation shifts to the preliminary irradiation mode from #114. At step #114, flags FLF, FFF, and LCF1 are set to “1”.
and set FPF to “0”. Flag FLF is a flag to indicate that it is in preliminary irradiation mode.
FFF is a flag that becomes "1" when the first measurement is performed in the preliminary irradiation mode, and LCF1 is a flag that becomes "1" as soon as it is determined that the contrast is low. In step #115, terminal 01 is set to "High" to perform focus detection operation in preliminary irradiation mode, and step 08
By setting “High” and operating in preliminary irradiation mode, A-D by microcomputer MCO2 is performed.
Sends a signal instructing the conversion operation to be inhibited. Then, it is determined whether a signal indicating that A-D conversion is in progress is input from the microcomputer MCO2 to terminal i5, and if terminal i5 is "High" and A-D conversion is in progress, A-D conversion is performed. After completing the process and waiting for i5 to become "Low", the focus detection operation moves to perform preliminary irradiation.

In step #117, a constant value T0 is set in a timer counter TIC for counting a constant time (for example, 200 msec) after performing preliminary irradiation. This counter TIC counts down based on the clock pulse inside the microcomputer MCO1, and when the internal value reaches "0", a timer interrupt is generated if a timer interrupt is possible, and #260 (described later)
Perform the operation of the step and return to the original flow.
In #118, the flag RSF is set to "1". This flag RSF is set to "1" until a certain period of time has elapsed after preliminary irradiation, and when a timer interrupt occurs after the elapse of the certain period of time, it is set to "0" at step #260. And this flag RSF
While is "1", the output terminal 07 becomes "High" and the microcomputer MCO2 does not shift to the exposure control operation. Note that when timer interrupts are disabled, no interrupt operation is performed even if timer TIC becomes "0", and when timer interrupts are enabled, timer interrupts are immediately activated and the timer interrupt operations are performed. It will be done. Flag RSF at step #118
When is set to "1", the process returns to step #2 and a focus detection operation for performing preliminary irradiation is executed.

When flag LLF is "0" in step #111, or flag SEF2 is set in step #113.
When is "0", the process moves to step #121 and starts operating in low contrast scan mode. First, flags LCF1, LCF2, and LSF are set to "1", and then the calculated defocus direction is determined, and the flag SIF is set to "1" or "0" depending on the determined direction, and the lens is set to that direction. move in the direction. Then, a warning is displayed and a flag is displayed.
When FPF is set to “0”, the contents of counter COF are “0”
When this occurs, the interrupt signal is not accepted and the process returns to step #2 to perform the next measurement.

If the flag FPF is “0” in step #110, the process moves to step #140 and the flag is set.
Determine whether FLF is “1”. flag FLF
If is "1", it means that the focus detection result in the preliminary irradiation mode is low contrast.
At this time, set the terminal 01 to “Low” and the 5th-
Proceed to step #200 in Figure 3. Then, in step #200, it is determined whether the flag FFF is "1". If the flag FFF is "1", it means that the first focus detection was performed in the preliminary irradiation mode, and in this case, the flag FFF is The flag is set to "0" and the process returns to step #115 to perform the second preliminary irradiation mode operation. On the other hand, #2
If the flag FFF is "0" at step 00, it means that the second measurement was performed in the preliminary irradiation mode, and in this case, a warning is displayed, a timer interrupt is enabled, and the process moves to step #211. and stop the operation.

If the flag FLF is "0" at step #140, then it is determined whether the flag TIF is "1" at step #142. If the flag TIF is "1", it is the low contrast stop mode, and the process returns to step #2 to perform the next measurement. #142
If the flag TIF is “0” in the step of
At step #143, it is determined whether SEF2 is "1". If it is "1", it means that even if the lens scans the entire area in low-contrast scan mode, only a low-contrast focus detection value can be obtained, and in this case, the low-contrast stop mode operation starts from #144. do.

In step #144, fixed data T1 is set in the counter COR, the mode is switched to a timer mode in which the contents of the counter COR are subtracted by the internal clock pulse of the microcomputer MCO1, and the flag TIF is set to "1" to enable counter interrupts. Return to step 2 and perform measurement. In this mode, focus detection is repeated with the lens stopped for a certain period of time, and if a measurement value that is not low contrast is obtained during this period, the lens is driven using the movement amount data based on this measurement value, and the lens is set to low contrast for a certain period of time. If only a focus detection value of 1 is obtained, the same operation as the first measurement is performed again.

If it is determined in step #143 that the flag SEF2 is "0", then in step #150 it is determined whether the flag LCF1 is "1".
If it is not "1", this means that the previous focus detection value was not low contrast, and the current focus detection suddenly became low contrast.
In this case, move to step #151 and flag
Set LCF1 to “1” and LCF2 to “0”, and terminal 0
4. Set 05 to "Low" to stop the operation of the motor MO, set the flag FPF to "1", and return to #2 to redo focus detection. If the flag LCF1 is "1" at step #150, then it is determined whether the flag LCF2 is "1" at step #155. And if flag LCF2 is “0”,
This is a case where the previous focus detection value suddenly becomes low contrast, and the current focus detection value obtained by redoing focus detection is also low contrast. Therefore, in this case, the above-described low-contrast scan mode starting operation is performed from step #121.

At step #155, flag LCF2 becomes “1”
When , it is operating in low contrast scan mode. In this case, the counter is set in step #156.
The contents of COR are set in register ECR3, and it is determined in step #157 whether the contents match the contents of register ECR2, which has taken in the contents of counter COR in step #27. If they do not match, the lens has not reached the end, so the process returns to step #3 and performs the focus detection operation. On the other hand, if the contents of registers ECR2 and ECR3 match, it means that the lens has reached the end, and #15
Stop driving the motor MO in step 8.
Then, in step #159, it is determined whether the flag SEF1 is "1" or not. If it is "1", it means that the lens has reached one end, and therefore the lens has reached both ends and is completely closed. This means that the area has been scanned. Therefore, at this time flag SEF2
Set it to “1” and move to step #112.
It is checked whether preliminary irradiation is possible from the flash, and if preliminary irradiation is possible, the system shifts to preliminary irradiation mode, and if preliminary irradiation is not possible, it shifts to low control stop mode.

If flag SEF1 is "0" in step #159, it means that the lens has reached the end for the first time in low contrast scan mode, and in this case, reverse flag SIF, reverse the rotational direction of motor MO, and set flag SEF1. Set it to "1" and return to step #3 to perform measurement.

If the flag FLF is "1" in step #41, it means that the result of measurement in the preliminary irradiation mode is not low contrast. At this time, the fifth
- Move to step #170 in Figure 3. #17
At step 0, terminal O1 is set to “Low”,
The lens movement amount ND and the focus area IFD are calculated from the defocus amount data LDt and the focus area data obtained in step #37, and the conversion coefficient KD, respectively. And at step #173 | ND
When |≦IFD, an in-focus display is performed, the flag FFF is set to "0", and the flow moves to step #211 to end the operation.

If it is determined in step #173 that |ND|>IFD, the process moves to #180 and sets |ND| to the counter COR, sets it to event count mode, enables counter interrupts, and disables timer interrupts. shall be. Then, it is determined whether the flag FFF is "1" or not, and if it is "1", it means that the first measurement was performed in the preliminary irradiation mode, and in this case, the process directly proceeds to step #188. On the other hand, if FFF is "0", this means that the second measurement has been performed. In this case, the process moves to step #178, and the data LND near the in-focus area is multiplied by the conversion coefficient KD to calculate the data NFD of the nearby area. And in step #179 |ND|≦NFD
Determine whether it is. ｜ND｜＞
In the case of NFD, it is considered that either the first focusing operation is not performed normally or the second focusing operation is unreliable. Furthermore, due to variations in conversion coefficients, etc., it is difficult to accurately move the lens to the in-focus position with just one movement, and it is considered that the focusing operation is basically impossible. Therefore, in this case, proceed to step #201 and issue a warning, then enable timer interrupts and #2
The process moves to step 11 and the operation is stopped.

In step #179, it is determined that |ND|≦NFD, and it is considered that control operation is possible.Next, the direction of movement is determined, and whether or not the direction of movement is reversed from the previous time is determined. Discern. And when it is determined that it is reversed |
ND｜+BLD calculation and movement amount data｜
Correct ND| by the backlash data and reset this data to the counter COR. On the other hand, if it is not reversed, the data set in step #180 is left unchanged and the process moves to #188. Then, the moving direction is determined, a signal corresponding to the direction is set in the flag SIF, and the motor MO is rotated in the determined direction.

Next, the contents of counter COR are stored in register ECR2.
Terminal i3 becomes “Low” after setting it to
If it is "Low", timer interrupt is enabled and the process moves to step #209. On the other hand, if it is "High", the process moves to #196 and the contents of the counter COR are set in the register ECR3. Then register at step #197.
Determine whether the contents of ECR2 and ECR3 match. And if ECR2≠ECR3 then ECR3
Set the contents in ECR2 and return to step #194. Therefore, in the preliminary irradiation mode, when data is obtained through measurement, the lens is driven based on this data, but no measurement operation is performed during this driving. Then, when the lens moves by the calculated amount of movement, a counter interrupt is generated and the lens is stopped as described later, and if it is the first time, it moves to the second operation, and if it is the second time, it displays the focus. to stop operation. Also, when it is detected in step #197 that the lens has reached the end, the terminal O
4. Set O5 to “Low” to stop the motor. Then, in step #200, it is determined whether the flag FFF is "1" or not. If it is "1", it is the first measurement, so the flag FFF is set to "0" and the process returns to step #115 described above for the second preliminary irradiation mode. Have them take measurements. On the other hand, if it is determined that the flag FFF is "0" in step #200, it means that the lens has reached the end due to the second operation, and in this case, a warning is displayed. Then, a timer interrupt is enabled, the process moves to step #211, and the operation is stopped.

When the contents of the counter COR become "0", a counter interrupt is generated and the operation starts from step #230. In step #230, it is determined whether the flag TIF is "1". When it is "1", a certain period of time has elapsed in the low contrast stop mode, and only low contrast measured values have been obtained during this time. At this time, interrupts are enabled and flags TIF, SFF1, and SEF
2. Set LCF1, LCF2, and LSF to "0", set flag FPF to "1", and return to step #2 as event count mode. Therefore, the measurement is performed under the same conditions as the first measurement.

When the flag TIF is "0" in step #230, it means that the lens has moved by the calculated amount of movement. In this case, the motor MO is stopped and an interrupt is enabled. Then, in step #235, it is determined whether the flag FLF is "1".
If it is “1”, it is the preliminary irradiation mode and #2
Move to step 38. In step #238, it is determined whether the flag FFF is “1” or not, and it is set to “0”.
If so, it means that the second focusing operation in the preliminary irradiation mode has been completed, a focus display is performed, a timer interrupt is enabled, and the process moves to step #211. On the other hand, if the flag FFF is "1", it means that the first focusing operation has been completed in preliminary irradiation mode.
The flag FFF is set to "0" and the process returns to step #115 to perform the second focusing operation.

If the flag FLF is "0" in step #235, this means that preliminary irradiation is not performed, a measured value that is not low contrast is obtained, and the lens has moved by the calculated amount of movement. At this time, the flag
Set IFF and FPF to "1" and return to step #2 to perform confirmation measurements.

When a timer interrupt occurs, the flag RSF is set to "0" in step #260 and the operation returns to the time when the interrupt occurred. Note that, like other interrupts, once a timer interrupt occurs, it is no longer possible to do so unless the interrupt is enabled.

When it is determined in steps #11, #19, #38, and #195 that terminal i3 has become “Low”, terminal it1 and the counter are determined in step #209.
COR interrupts are prohibited and the event count mode is set to proceed to step #213. on the other hand,
From steps #176, #203, and #243, the process moves to step #211, in which interrupts by terminal it1 and counter COR are disabled, and it waits for terminal i3 to become "Low". Then, when the terminal i3 becomes "Low", the process moves to step #213. At step #213, terminal O
4. Turn O5 “Low” to stop the motor MO, and then turn off the display. and terminals O1, O
2. Set O3 and O6 to "Low" to stop the operation of the automatic focus adjustment circuit. And RSF,
Set all flags except FPF and SIF to "0" and set flag FPF to "1". Next, set the contents of counter COR in register ECR2, and after a certain period of time, register the contents of counter COR.
Set to ECR3. Then, it is determined whether ECR2=ECR3, and if ECR2≠ECR3, the contents of register ECR3 are set in register ECR2, and the process returns to step #219. and ECR
If 2=ECR3, the movement of the lens has completely stopped, and the process moves to step #223.

At step #223, flag RSF is “1”
If it is “1”, it means that a certain period of time (200 msec) has not elapsed since preliminary irradiation, and the flag RSF becomes “0” after the certain period of time has elapsed.
Wait until it becomes. Then, when the flag RSF becomes "0" or is "0", the microcontroller sets terminal O7 to "Low" in step #244.
Exposure control operation by MCO2 is possible, and the terminal it
The microcomputer MCO1 stops operating, allowing interrupts to the microcomputer MCO2.

Effects As described above, according to the automatic focus adjustment method of the present invention, the drive amount obtained in the last focus detection is compared with a predetermined value, and the next operation is controlled based on the comparison result. . That is, if the amount of drive is smaller than a predetermined value, the photographing lens is driven based on this amount of drive, and after the end of the drive, it is displayed that the in-focus state has been reached. Further, if the driving amount is larger than a predetermined value, a warning display is performed without driving the photographing lens. Therefore, if the drive amount calculated based on the last focus detection result is larger than a predetermined value, that is, if the focus detection result is unreliable, no drive is performed, and unnecessary movement of the photographic lens is avoided. Can be suppressed.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the basic configuration of a camera to which this invention is applied, Fig. 2 is a circuit diagram showing the entire camera system to which this invention is applied, and Fig. 3 is a block diagram showing the basic configuration of a camera to which this invention is applied.
A circuit diagram showing a specific example of the flash circuit FLC shown in the figure, Fig. 4 is a flowchart showing the operation of the microcomputer MCO2 shown in Fig. 2, and 5-1, 5-2, 5-3.
The figure is a flowchart showing the operation of the microcomputer MCO1 shown in FIG. First step...#1-5-20, Second step...#24-41-170-173-19
3. Third step...#230-235-24
0-115-118-2-5-20, 4th step...#24-41-170-173-183
~179, 5th step...#184~19
3. Sixth step...#201.

Claims (1)

[Claims] 1. A first step of detecting the focus of the subject by receiving the subject image formed by the photographing lens while emitting auxiliary light to illuminate the subject; and detecting the focus of the subject in the first step. A second step of calculating the driving amount of the photographing lens necessary to focus on the subject based on the focus detection result and driving the photographing lens based on this driving amount, and again after the second step is completed. The third step is to perform focus detection while emitting an auxiliary light, and the amount of drive of the photographic lens necessary for focusing is calculated based on the focus detection result detected in the third step. A fourth step in which the driving amount is compared with a predetermined value; and as a result of the comparison in the fourth step, if the calculated driving amount is smaller than the predetermined value, the photographing lens is driven based on this driving amount, and the lens is driven. After the completion of the comparison, the fifth step displays that the in-focus state has been reached, and as a result of the comparison in the fourth step, if the calculated drive amount is larger than a predetermined value, a warning is displayed without driving the photographing lens. A camera automatic focus adjustment method consisting of a sixth step to perform.