JPH0830780B2 - Automatic focus adjustment device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focus adjusting device for a camera, and more particularly to an automatic focus adjusting device that drives a taking lens in various modes.

[Prior Art] The light fluxes from the subject that have passed through the first and second regions of the taking lens, which are symmetrical to each other with respect to the optical axis, are re-imaged to form two images. Determining the mutual positional relationship of the two images, the deviation amount and direction of the image formation position from the planned focus position (whether the image formation position is in front of the planned focus position,
A focus detecting device for obtaining the rear side, that is, the front focus or the rear focus has already been proposed. The optical system of such a focus detection device has, for example, a configuration as shown in FIG. 24. This optical system has a planned focal plane (4) behind the taking lens (2) or further behind this plane. It has a condenser lens (6) at the position and further has re-imaging lenses (8) and (10) behind it. For example, a CCD is provided on the image plane of each re-imaging lens (8) (10). Image sensors (12) and (14) as light receiving elements are arranged. Each image sensor (1
2) The image above (14) is close to the optical axis (18) in the case of the so-called front focus where the image of the object to be focused is formed in front of the planned focal plane, as shown in Fig. 25. Approach each other,
On the other hand, in the case of rear pins, they are far from the optical axis (18). When the two images are in focus, the distance between the two points corresponding to each other is a specific distance defined by the configuration of the optical system of the focus detection device. Therefore, in principle, the focus state can be known by detecting the interval between two corresponding points of the two images.

In an automatic focus adjustment device for a camera with a built-in focus detection optical system, the CCD image sensor integrates the light amount of the subject, the focus detection calculation (defocus amount calculation) using the CCD image sensor output, and the defocus amount The sequence of lens driving, stopping at the in-focus position, and shutter release is program-controlled by a control circuit composed of a microcomputer.

This automatic focus adjustment device continuously performs the above-described sequential automatic focus adjustment control even when the subject image is near the in-focus position, so that the in-focus position can be finally set accurately. Automatic focus adjustment (AF).

By the way, in the case where the subject is approaching or moving away from the camera with the above-described automatic focus adjustment device, the defocus amount is detected by one focus detection and the defocus amount is detected based on the defocus amount. When the photographing lens is moved to the in-focus position by moving the subject, the subject is not in focus because the subject is moving during that time.

Figure 26 shows the situation. The horizontal axis is the time axis, and the vertical axis is the defocus amount on the film surface. In the figure,
The curved line 1 shows the degree of increase in the defocus amount on the film surface when the subject approaches, and the straight line m traces the position where the photographing lens is about to form an image.

The point of time when the subject data is captured is the center A, B,
Let me show you C ... In FIG. 26, T ₀ is the first integration center point. The defocus amount at this time is set to D ₀ . (T ₀
~ T ₁ ) is the time required for focus detection calculation from the center to the end of the integration time. When the lens drive is completed, the lens is stopped and the next integration (T _{2 to} T ₃ ) and calculation (T _{3 to} T ₄ ) are started again. Lens stop time T ₂ the already subject is moving, the defocus amount of already when compared to T ₀ point (D ₁ -D ₀₎ has occurred. The data of the next subject was captured by T ₃
In, it is a T ₅ to finish driving the lens seek the defocus amount (D ₂ -D _1). At this time, the subject has already moved, and even after the lens has been moved, the defocus amount is further generated (D ₃ −D ₂ ), and the defocus amount becomes larger than that at the time point T ₂ . Similarly, the defocus amount at T ₈ is (D ₅ −D ₄ ), and at T ₁₁ (D ₇ −D ₆ ), the point of approaching the focusing zone is conversely distant and AF is in effect. As a result, a delay will occur and shutter release will not be possible when the subject is in focus.

The tracking delay due to such AF control becomes a problem particularly when a long-focus interchangeable lens such as a telephoto lens having a slow focusing speed is used.

The applicant of the present application has proposed one method for solving such a problem in Japanese Patent Application No. 60-280789. This method will be briefly described with reference to FIG. 27. The defocus amount of integral I ₂ is DFB, the defocus amount at integral I ₃ is DFC, and the integral
Defocus amount D when the defocus amount at I ₄ is DFD
If FB <DFC <DFD, the defocus amount DF
D is the difference from the defocus amount DFC calculated by the previous calculation Z = DFD
-By adding a new defocus amount by adding DFC, the delay amount is reduced as much as possible for a moving subject. In FIG. 27, it is understood that the defocus amount when the lens is stopped (at the start of the line segment I ₅ ) is reduced from X to Y by correcting the defocus amount difference Z.

[Problems to be Solved by the Invention] However, since there is a time delay (so-called release time lag) from the time when the shutter release operation is performed until the time when the shooting actually starts, when the subject is moving. Even if the photographing lens is driven following the movement of the subject as described above, the defocus amount may increase again during this release time lag.

Therefore, an object of the present invention is to provide an automatic focus adjustment device capable of favorably focusing on a subject even if the subject moves during such a release time lag.

[Means for Solving Problems] An automatic focusing apparatus according to the present invention detects an image of a subject and converts it into an electric signal, and based on an output of the imaging unit, a focusing lens from a focus position of a photographing lens. First calculation means for calculating the defocus amount, driving means for driving the taking lens, signal output means for outputting a start signal for starting exposure control, and predetermined release operation when the start signal is output. In an automatic focus adjusting device having an exposure control means for starting exposure after the movement, a movement detection means for detecting movement of an object in the optical axis direction based on a plurality of defocus amounts obtained by the first calculation means, and a release. Output means for outputting the release time lag from when the exposure is actually started, the movement of the subject detected by the movement detecting means, and the output means. A second calculation means for predicting a change amount of the defocus amount that may occur due to the movement of the subject in the optical axis direction during the release time lag based on the output release time lag, and the start signal. In the period from the output to the start of exposure, the second
Drive control means for controlling the drive means based on the output of the calculation means.

[Operation] According to the above configuration, the defocus amount from the in-focus position of the photographing lens is repeatedly calculated for the moving subject by the “first calculating means”, and the calculated defocus amount is calculated from the calculated plurality of defocus amounts. The movement of the subject in the optical axis direction is detected by the "movement detecting means".

Now, when the "signal output means" outputs a start signal for starting the exposure control, in response to the output of the start signal, the movement of the subject detected by the "movement detection means" and the "output means" Based on the release time lag output by ", the change amount of the defocus amount that would occur due to the movement of the subject in the optical axis direction during the release time lag is predicted and calculated by the" second calculating means ". . Then, during the period from the output of the start signal to the start of exposure, the "drive control means" drives the photographing lens based on the result of the predictive calculation by the "second calculation means". A focused state can be obtained at the timing of starting exposure.

[Example] FIG. 28 is a graph for explaining the principle of the present invention.
The meaning of the vertical and horizontal axes is the same as in FIG. If it is determined that there is a tracking delay with respect to the subject based on the defocus amounts D ₅ and D ₆ at the time P ₁ when the lens is stopped, the calculation C ₆ at integration I ₆ will follow at the time P _1. The correction is applied and the lens is not stopped at Q ₁ , but the lens is moved further by the correction amount WR and brought to Q ₂ . The correction amount WR will be described later, but the amount of movement when the subject moves in the optical axis direction of the photographing lens of the camera is taken as the defocus amount on the film surface of the camera. This movement amount is the unit cycle of focus detection
Converted to the slope per TI and calculated. In the case of FIG. 29,
The next lens drive time is considered as TI, and at the latest, it will catch up after the time TI. Goodbye, this time TI
There is a delay in tracking the speed of the subject that requires the lens to be driven for a time exceeding the correction amount WR in, but unless the subject is particularly fast, the shooting lens enters the range that can be determined to be in focus. You can say that you are catching up with the subject. Also, in this model, the movement of the subject is assumed to be a linear function of the defocus amount on the film surface, but in reality, for example, when the subject approaches the camera at a constant speed, the defocus amount The change of is not a linear function, but a higher-order function. In this case as well, the correction amount is insufficient even if the follow-up correction is made, but it can be said that the correction amount is still in the in-focus range, so the target correction position in the case of FIG. 28 is the midpoint of the integral I ₈ . it is a P _3.

Since the middle point P ₀ of the integrating I ₆ to the end P ₁ of the operation C ₆ does not move the lens, tracking delay of the object is also occur during this time. It is necessary to consider the delay and the delay during the next driving of the lens (in this period, one cycle of integration and calculation is included). That is, when the subject moves and the tracking delay occurs while the lens is stopped, the movement of the subject from the integration I ₆ through the integration I ₇ to the midpoint of the integration I ₈ is predicted, and correction is performed at the time point P _1. You need to call. That is, in this case, P ₁
You just have to add 2WR correction.

Because the midpoint of the integration I ₈ of this goal, as viewed from P _1, having substantially the same meaning as that of the point P ₂ the result of the next integration I ₇ comes out to target. Because the integration time is short here, it is assumed that P ₂ ≒ P ₃ . Here, the calculation takes 50 msec, while the integration is several msec or less.

FIG. 29, at P ₄ in the lens drive, showing a case where it is determined that the follow delay with respect to the subject based on the defocus amount of D ₃ and D ₄ occurs. Further, it shows a state where the lens is being driven in the state where the tracking correction is continuously added while the object is being tracked in the tracking mode including the case where it is determined that the tracking mode is entered during the stop. When the correction enters the tracking mode when P ₄ such drives the defocus amount by lens which is calculated based on data obtained by integrating I _3, without stopping the lens in Q ₁ be finished driving, further 2WR
Move minutes. As in Fig. 28, the correction target time is
Integral by P ₆ based on the result of the operation based on I ₆ data
It is the midpoint of I ₇ . This corresponds to exactly two cycles of the focusing effect calculation from the midpoint of the integral I ₄ where the tracking delay is detected. This is to attempt to correct and drive a total of two cycles including one cycle taken until the present detection result is obtained within one cycle time when the next result is obtained. In the following, the same operation is repeated, but if the lens drive cannot catch up, that is, if the drive count value to which the correction value is added during the follow-up mode is larger than the predetermined count value, the lens drive speed is switched. . In the figure, it is switched at the Q _2. Even if the drive speed is switched,
The correction value and the target value are considered in the same way. If it catches up on the way and the driving direction is reversed according to the calculation result, the follow-up correction is not performed.

Next, a method of calculating the inclination per unit period TI of focus detection with respect to the movement of the subject in the camera optical axis direction will be described with reference to FIG.

In the figure, the unit focus detection cycle is defined as S _{1 to} S ₂ , S
₃ to S ₄ or T ₁ through T _3, a T ₁ '~T _3' and the like. Then, assuming that these are continuous and the same subject is viewed, each time is regarded as the same. The current position is calculated as C ₃ .
The defocus amount obtained by the previous integration is LERR. Incidentally, this is the obtained is a time of T _3. The defocus amount obtained by this integration is defined as ERR. This is obtained at T ₃ ′.

The defocus amount corresponding to the movement amount of the subject per unit cycle, that is, the inclination WR is obtained as WR = ERR + ITI-LERR from the figure. Here, ITI is a lens movement amount from the previous integration to the current integration. The relative positions of the previous integration center of the lens is obtained as 1/2 of the sum of the relative positions of the integration start time T ₁ and the end time T ₂ of the lens. T ₁ and T ₂ are values obtained by converting the defocus amount LERR ′ at the time of S ₁ into a lens drive count number in the operation C ₁ and setting the value in the event counter. On the other hand, a focusing encoder is set on the lens, and when the lens moves, a pulse is output from the encoder. This signal is connected to the input of the event counter, and the event counter counts down each time a pulse comes. Therefore,
The amount of lens movement can be known by reading the value of this event counter. These values are T ₁ and T ₂ . Therefore, (T ₁ + T ₂ ) /
2 = Find the center of the previous time with MIL.

Next, a case where the shutter is released during the AF in the follow-up mode will be described with reference to FIG. In the present invention, the lens is driven even during the release time lag in order to improve the followability. That is, the lens is driven even before the exposure operation is started after the release signal is input, for example, while the reflex mirror of the single-lens reflex camera is raised.
However, since the mirror is raised during this time, focus detection (integration and calculation) cannot be performed by the focus detection method of detecting focus by receiving light passing through the mirror. Therefore, the amount WS by which the subject moves while the mirror is moving up is calculated in advance. Assuming that the release time lag time is RTS, from the subject movement WR per unit focus detection time TI, WS = WR ×
RTS / TI. This WS is set as a tracking correction amount, and the lens is moved and stopped before the exposure operation. Then, after the exposure of the film, the lowering of the mirror starts, and at the same time, the automatic winding of the film and the winding operation of shutter cocking are started. (It is not always necessary to perform automatic winding.) At this time, the camera is in the release priority mode in which the shutter release is prioritized over reaching the in-focus state, and before the camera is focused. Assume that the shutter has been released. The result of shooting is naturally blurred, but if the camera is in continuous shooting mode in which continuous shooting is performed, the second and subsequent photos should be in focus as much as possible. Therefore, while the mirror is descending (during this time, integration and calculation cannot be resumed until the mirror is stabilized at the lowered position.) The lens is driven by an amount that does not reach the in-focus state during exposure before the integration is resumed. . In the figure, the lens is stopped when integration is restarted, but there is no problem if integration is performed while moving.

FIG. 1 is a block diagram of a camera control circuit used in an embodiment of the present invention. (1) a microcomputer (hereinafter referred to as a microcomputer) for controlling and calculating the sequence of a camera, and (2) opening and closing a shutter according to an exposure start / end signal from the microcomputer (1), and a mirror-up signal. Exposure control circuit for performing mirror-up and aperture control according to (1), (3) digitizes a signal corresponding to the luminance of the subject by a photometric circuit, and sends it to the microcomputer (1).
(4) is a film sensitivity automatic reading circuit, which digitizes film sensitivity information and sends it to the microcomputer (1).
(5) is a one-frame winding circuit which drives the motor in response to a signal from the microcomputer (1) to wind the film by one frame, and stops driving the motor by turning on the one-frame winding detection switch (S9). (6) is a setting circuit for setting the aperture value and shutter speed, and (7) is ON / OF of the switch (S1).
A pulse generation circuit that generates one pulse each in synchronization with F, (8) is an interface circuit provided between the CCD (9) used for focus detection and the microcomputer (1),
A signal from the microcomputer (1) controls the start and end of charge accumulation in the CCD (9) and A / D-converts the data in the CCD (9) and outputs it to the microcomputer (1).

(10) is a motor control circuit that controls a motor (M) that drives a focus adjustment optical system (not shown) for focus adjustment based on a signal from the microcomputer (1),
(11) is an encoder that monitors the rotation of the motor (M), and generates 16 pulses each time the motor (M) makes one rotation. Reference numeral (12) is a lens circuit provided in the taking lens, which sends unique data to each lens to the microcomputer (1). (13) is an auxiliary light emitting device used at the time of focus detection. (14) is a display circuit for displaying a focus detection state, and (15) is a timer for generating a release signal at regular time intervals in continuous shooting mode in which shooting is continuously repeated. (E) is a power supply battery, which is a microcomputer (1), a switch described later, a reset resistor (RR), and a capacitor (C).
R) and power supply transistor (Tr ₁ ) are directly supplied with power. Power supply transistor (Tr ₁ ) for other circuits
Is supplied with the voltage of the battery.

Next, the switch will be described. (S1) is turned on by the first stroke of pressing a release button (not shown), and the microcomputer (1) executes the flow (AFS) described later by turning on the switch (S1) or turning off the release button. (S2) turns on when the release button is pressed down to the second stroke longer than the first stroke, and this ON causes the microcomputer (1) to execute a release flow described later with reference to FIG. 16 (a). (S3) is a switch that turns on when the mirror is up, and when the release member (not shown) is charged by winding the film by the one-frame winding mechanism, the switch (S3) turns off.
It becomes the state of. (S4) is a so-called one-shot mode in which the focus detection operation is stopped once the photographing lens reaches a focus state, and a so-called continuous mode in which focus detection is continued even once the focus state is reached. Switch to select. (S5) is an exposure mode setting switch, which outputs a 2-bit signal to the microcomputer (1) according to the set mode.
Sent to The exposure control mode of the camera according to the present embodiment includes a program mode (hereinafter referred to as P mode), an aperture priority mode (hereinafter referred to as A mode), a shutter speed priority mode (hereinafter referred to as S mode), and a manual mode (hereinafter referred to as M mode). There are four types.

(S6) is a release priority mode in which the shutter release is prioritized regardless of the focus state, and a focus priority mode in which release is permitted or prohibited depending on the focus state (hereinafter, referred to as "S6").
Switch to switch between AF priority mode) (S7)
Is an end detection switch for detecting that the lens driven at the time of focus detection has been driven to the latest or the farthest or infinity in-focus position. Is executed. (S8) is a changeover switch for switching between continuous shooting mode and one-frame shooting mode, (S9) is turned on when exposure is completed,
This is a one-frame winding detection switch that turns off when one-frame winding is completed.

In the above circuit configuration, when a battery is installed in the camera, power is supplied to the reset resistor (RR) and capacitor (CR), and the reset terminal (RE) of the microcomputer (1) changes from "Low" level to " A signal that changes to "High" level is input, and the microcomputer (1) resets the reset routine (RE
SET). The microcomputer (1) first resets the flag and the output port to an initial state (# 5, # 10).
Next, turn off the auxiliary light emitting device (13), turn off the display,
The lens drive is stopped, the motor is driven when the film winding is not completed, and the power supply transistor (Tr ₁ ) is turned off when the film winding is completed (# 15 to # 30). Then, the auxiliary light flag (auxiliary light F) for emitting auxiliary light is reset, the terminal (OP3) is set to the "Low" level, and the microcomputer (1) is stopped (# 35, # 40). The above steps # 15 to # 40 are mainly effective when shifting from step # 55 described later.

When the release button is pressed in the first stroke with the battery attached, the switch (S1) turns on and the microcomputer (1) executes the flow from AFS in FIG. The microcomputer (1) first resets all the flags and turns on the power supply transistor (Tr ₁ ). As a result, power is supplied to each circuit, and at the same time, the photometry circuit (3) starts photometry. The microcomputer (1) determines whether or not the switch (S1) is ON. If the switch (S1) is OFF, the process proceeds to step # 15 to perform the above-described processing. If the switch (S1) is ON, the next focus detection and subsequent processing are performed. Execute the flow (# 55). When the switch (S1) is ON, it is determined whether or not the auxiliary light flag (auxiliary light F) is set. Proceeding to step # 70, if the auxiliary light flag is not set, skip step # 65 and proceed to step # 70 (# 60, # 65).

Next, the microcomputer (1) reads the time (TI) taken from the start of the previous integration to the start of this integration by the timer (TI), and then resets and starts this timer (TI). And start integration (# 70 ~ #
78). In order to detect the relative position of the lens at this time, the value (CT1) of the counter (hereinafter referred to as the event counter) indicating the amount to drive the lens to the in-focus state is read (# 8
0). Next, a flag (long product F) indicating whether or not the mode is a long integration time mode is determined. If the flag is set, wait for 80 msec to elapse. Then, the auxiliary light emitting device (13) is turned off, and the process proceeds to step # 110 (# 85 to # 95). When the flag (long product F) is not set, the procedure proceeds to step # 110 (# 100, # 105) when 20 msec has elapsed even when the integration is completed or even when the integration is not completed. The integration is terminated when the amount of light incident on the light receiving element of the integration time control monitor provided near the CCD (9) becomes equal to or greater than a predetermined value. Is omitted.

In step # 110, the value of the event counter is read as (CT2) in order to know the relative position of the lens at the end of the integration. Further, the microcomputer (1) dumps CCD data and performs focus detection calculation using this data (# 120, 125). Next, let MIL be the value (MI) indicating the relative position of the lens at the previous integration center, and calculate the lens relative position (CT1) at the start of integration and the lens at the end of integration to find the relative position of the lens at this integration center. Divide the sum with the relative position (CT2) by 2 and set this value as MI (# 130,
# 135). Next, we try to find the amount of lens drive from the previous center of integration to the center of integration this time.
-MI does not work.

The reason will be described with reference to the graph of FIG. In this graph, the horizontal axis represents time, and the vertical axis represents the movement amount with respect to the movement (a) of the subject image and the movement (b) of the lens on the film surface. In this case, integration and calculation are performed while driving the lens. T ₁ , T ₁ ′, T ₁ ″ indicate the integration start time, T ₂ , T ₂ ′, T ₂ ″ indicate the integration end time, T ₃ , T ₃ ′, T ₃ ″ indicate the operation end time,
Now, it is assumed that T ₁ ′ ≈T ₃ ″, T ₁ ≈T ₃ ′. The reason is that the time required for focus detection depends on the integration, data dump,
This is because most of the focus detection calculation (# 60 to # 125) is spent. The MIL indicating the lens relative position of the center of the previous integration I ′ is the integration start time T ₁ ′ and the integration end time.
Add the value of the event counter indicating the lens position of T ₂ ′ and divide by 2 and insert it. End point T ₁ ′ of operation C ″
As the result of the calculation C ″, a value obtained by converting the defocus amount from the subject position RE1 into the movement number of the encoder is input to the event counter of.
It is a position indicating the defocus amount from the image plane at the central point of the integration I ″.

Next, MI indicating the relative position of the lens at the center of the current integration I includes the subject position RE
Enter the value obtained by converting the defocus amount from 2 to the number of encoder movements. Therefore, MIL, which indicates the relative position of the lens,
The MI has different scale values between the scale with the previous result as the origin and the scale with the current result as the origin. Even if this is simply MIL-MI, the exact amount of lens movement cannot be calculated. If the scales are not aligned, an accurate lens movement amount cannot be obtained.

Therefore, this correction amount is defined as DT. This value DT is a value of the event counter from the object position RE1 showing a lens position of the operation C 'end T _3' (CT3), and converts the operation result value DF2 'at this time the movement speed of the encoder value (LER
R). That is, DT = LER
Obtained by R-CD3. And the amount of lens movement (IT
I) can be obtained by subtracting the above DT from the relative position MI of the lens at the center of integration this time, and subtracting it from MIL.
That is, ITI = MIL- (MI-DT) is obtained. The microcomputer (1) does this in steps # 140 and # 145 of FIG.

Next, the microcomputer (1) uses the lens circuit (12) to input the data of the aperture value Av ₀ and the coefficient value (hereinafter referred to as KL value) for converting the defocus amount into the number of pulses of the encoder. Read the data from the ROM of the circuit (12).
First, the chip select terminal (CS) is set to "High" level, a signal indicating the start of data communication is output, and a variable N indicating the number of read data is set to 0 to execute a serial communication command (# 155, # 160). According to this instruction, a clock is output from the terminal (SCK) of the microcomputer (1), and data is output from the lens circuit (12) bit by bit in synchronization with the rise of the clock. Then, in synchronization with the falling of this clock, the microcomputer (1) connects the terminal (SI
By reading the data from N) and outputting eight pulses, one serial communication is completed. This is performed twice, and the above two types of data are input from the lens circuit (12) (# 165, # 170). When the two types of data have been input, the terminal (CS) is set to the "Low" level to notify the lens circuit (12) of the end of the serial communication (# 175). Next, the process proceeds to a subroutine for exposure calculation (# 180).

This subroutine will be described with reference to FIG. First, the microcomputer (1) sets the open metering value Bv ₀ to the metering circuit (3).
The film speed data Sv is input from the film speed automatic reading circuit (4) (# 2000, # 2005).
The exposure value Ev is calculated from these data and the open aperture value Av ₀ input as described above (# 2010). Next, the exposure control mode is determined, and if it is the P mode, the exposure value Ev is halved to obtain the aperture value Av, and the aperture value Av is subtracted from the exposure value Ev to obtain the shutter sensitivity value Tv. Return (# 2015 ~ # 2025). In the case of the A mode, the set aperture value Av is read, the set aperture value Av is subtracted from the exposure value Ev to obtain the shutter speed value Tv, and the process returns (# 2030 to # 20).
40). In the S mode, the set shutter speed value Tv is read, the set shutter speed value Tv is subtracted from the exposure value Ev to obtain the aperture value Av, and the process returns (# 2045 to # 2055). If none of the above modes, that is, the M mode, the set aperture value Av and shutter speed value Tv are read and the process returns (# 2026 to # 2065).

Returning to the flowchart of FIG. 2, when the exposure calculation is completed, it is detected from the result of the focus detection / calculation whether or not focus detection is impossible. If it cannot be detected, the flow advances to LOWCON. If it can be detected, the low contrast flag LCF indicating that focus detection is impossible
Is reset, and it is determined whether or not it is low light (the subject has a low brightness equal to or lower than a predetermined value) (# 185 to # 19).
Five). If it is not low light, the auxiliary light flag is reset in step # 200, and if it is low light, step # 200 is skipped, and the process proceeds to step # 205. Read on the counter. Next, the defocus amount Δε obtained in this calculation is multiplied by the conversion coefficient KL value to obtain the number of pulses of the encoder. It is set to 0 (# 205 to # 225).

Next, the accuracy check subroutine is entered. In the focus adjustment device used in the present embodiment, in the focus adjustment, an accuracy priority mode in which priority is given to focusing accuracy over time to reach the focusing state, and a speed at which the focusing state is reached than the accuracy is increased. It has a speed priority mode that prioritizes the operation. The speed of the lens control motor relating to this will be described later. In this subroutine, the above two modes are switched depending on the type of lens or various conditions at the time of shooting. This can take various forms.

For example, as shown in FIG. 5 (a), when the continuous mode is used, the focus is often adjusted for a moving subject, so the speed priority mode is set, and when the one-shot mode is set, the still subject is focused. Since it is often adjusted, the accuracy priority mode is set. Alternatively, as shown in FIG. 5 (b), in the A mode, it is considered that it is often desired to accurately focus on a still subject such as a portrait, so the accuracy priority mode is set, and other exposure control is performed. In the mode, the speed priority mode is set. Alternatively, as shown in FIG. 5 (c), when the controlled aperture value (F value) is smaller than 1.7, it is considered that it is often used for portraits and the like, and therefore the accuracy priority mode is set. , Considering that the depth of field of the lens is also somewhat deeper, the speed priority mode is set. This limit F value may be arbitrarily selected as long as it is between F4 and 5.6. Further, as shown in FIG. 5 (d), when the KL value for converting the defocus amount into the number of encoder pulses is large, that is, in a lens in which the change amount of the defocus amount per pulse number is small, it takes time to adjust the focus. And the speed priority mode, and when the KL value is small, the opposite is true.
If the lens driving speed is too fast, accurate focus adjustment cannot be performed and the accuracy priority mode is set. In the latter case, even in the accuracy priority mode, the focus state will be achieved with a small number of pulses, so
The time required for focusing is relatively short.

In this embodiment, the flow is as shown in FIG. 5 (e) so as to include all the judgments in the above four cases, and the judgment state is shown in Table 1. Here, regarding the case classification of the accuracy priority mode and the speed priority mode, the mode having the most priority mode is the mode at that time. When the number of priority modes is the same, priority is given to the threshold value of the aperture value. This is because a lens having a small F-number has a very shallow depth of field, and is likely to be out of focus even with a slight shift.

Returning to FIG. 2, after finishing the accuracy check mode, it is detected whether or not the lens is stopped (# 235). This can be seen by detecting the drive signal to the motor. If the lens has stopped, proceed to the MFZ routine, and if not, proceed to the IDOBUN routine.

First, the MFZ routine will be described with reference to FIG. To memory the defocus amount Δε to another variable Δε _1, focusing the number of zones pulse over the KL value to the amount of the in-focus zone ΔIF (40μ)
Ask for IFP. Next, the value of the amount of the lens moved from the integration center to the end of the calculation is set to a value CTC represented by the number of encoder pulses of 0 (# 240 to # 250). Next, it is determined whether or not ERR, which indicates the defocus amount Δε by the encoder pulse number (hereinafter referred to as the defocus pulse number), is 3 pulses or less, and if it is 3 pulses or less, the current defocus pulse The number ERR is the previous defocus pulse number LERR, the current defocus direction TD is the previous direction LD, and the focus flag (focus F) indicating the focus is set and the focus display is performed (# 255). ~ # 275). Then, a flag (AFEF) indicating the end of the focus detection is set, and it is determined whether or not the mode is the continuous mode from the state of the switch (S4). from
The flow proceeds to the CDINT routine to perform focus detection again. If the microcomputer is in the one-shot mode, the microcomputer (1) does not perform focus detection after waiting for an interrupt.

In step # 255, if the defocus pulse number ERR exceeds 3, it is determined whether the focus flag (focus F) is set, and if it is set, the defocus pulse number ERR is set in advance. It is determined whether the number of pulses is within the focusing zone pulse, and if it is within the focusing zone, the routine proceeds to the INFZ routine from step # 260 (# 290, # 295). When the focus flag (focus F) is not set in step # 290, the current defocus direction TD and the previous defocus direction LD are reversed, or even when they are not reversed, the near zone described in detail later If it is determined in the A determination subroutine that the vehicle is not in the near zone (NZF = 1), the flag (1STF) indicating that the vehicle has passed once is reset, and the process proceeds to step # 295 (# 370 to # 380).

The subroutine of the near zone A determination will be described with reference to FIG.

The microcomputer (1) first calculates the number of defocus pulses ERR as E
Use RR1 to determine whether the lens is stopped (# 3000, #
3005). If it is stopped, the process proceeds to step # 3015, and if it is not stopped, the lens movement amount CTC from the integration center to the end of calculation is subtracted from ERR1 and the process proceeds to step # 3015. In step # 3015, it is determined whether or not the following flag (following F) indicating the following mode is set. If it is set, the counter NZC indicating the near zone range is set to 63. In the non-following mode (when the follower flag is reset), set the near zone counter to 100 in the speed priority mode, set the near zone counter to 120 in the accuracy priority mode, and then step # 3035.
Proceed to (# 3015 to # 3030). In step # 3035, it is determined whether or not the defocus pulse number ERR1 is less than or equal to the count value NZC of the near zone counter, and if the count value of the near zone counter is less than or equal to NZC, the flag NZF indicating the near zone is set. If the count value of the near zone counter exceeds NZC, near zone flag NZF
To reset and return (# 3035 to # 3045).
Here, in this embodiment, the range of the near zone is changed depending on whether the speed priority mode or the accuracy priority mode is used.
In this case, since it has nothing to do with the speed control of the motor, a fixed value such as 100 may be used.

Returning to FIG. 6, when it is determined in step # 380 that the near zone flag (NFZ) is set,
After this step, when the defocus amount increases for a moving subject, a flow for correcting the defocus amount will be shown, and such a case will be referred to as a following mode. In step # 385, it is determined whether or not the flag (1STF) indicating that the vehicle has passed once is set. When the flag (1STF) is not set, the flag (1STF) is set, the flag (following F) indicating the following mode is reset, and a following correction flag (following correction) indicating that the correction is further performed. F) is reset and the process proceeds to step # 300 (# 455, # 460, # 445). Step # 38
If the flag (1STF) indicating that the vehicle has passed once in 5 is set, the previous defocus direction (LD) and the current defocus direction (TD) are distinguished, and if the directions are different,
That is, if the directional data is 1,0 or 0,1, the process proceeds to step # 460, and the tracking correction in the tracking correction mode is not performed.
If the previous defocus direction (LD) and the current direction (TD) are the same direction, that is, if the data of both are 0, 0 or 1, 1, the process proceeds to step # 400 and the follow flag (follow F) is set. It is determined whether or not (# 390 to # 400, # 450).
If the follow-up flag is not set in step # 400, the previous defocus pulse number LEER is subtracted from the current defocus pulse number ERR to obtain WR (# 430).
If this value WR is larger than the predetermined amount AA, that is, if the defocus amount (pulse number) is large, the follow-up flag (following F) is set, but in this embodiment, WR becomes a positive value twice. Since the correction is performed at the time of performing, the follow-up correction flag (following correction flag) indicating the correction in the follow-up mode is reset so that the correction is not performed for the first time (# 435, # 440, # 445). . The predetermined amount AA is a value determined in consideration of the noise component, and may be set to 0 if the configuration has no noise component. If the WR is equal to or less than AA, the defocus amount is not large, so that the flow proceeds to step # 460 without correction. When the tracking flag (following F) is set in step # 400, WR is obtained in the same manner as in step # 430, and whether or not this is larger than AA is determined. Since it is not necessary to perform the correction because it has caught up with, the process proceeds to step # 300 with WR as the correction amount set to 0 (# 405, # 410, # 425).

On the other hand, if it is determined in step # 410 that WR is larger than AA, the process proceeds to step # 415, and in step # 415, the difference WR between the previous and current calculation results is set to be larger than the count value NZC of the near zone counter. It is determined whether the set value AX is greater than or equal to the set value AX. The reason why the setting value AX is provided is as follows. In the following mode, that is, when the subject is moving, the subject may move out of the area provided for focus detection due to the movement of the subject. . This is because if the object deviates from this area, it will be focused on another object in the area, and this is to prevent this. For this reason, when the correction amount WR is equal to or more than the set value AX, it means that a desired subject has deviated from the area, and thus the lens movement amount is not updated. That is, when the correction amount WR is equal to or larger than the set value AX in step # 415, the non-update flag (non-update F) for prohibiting the update of the lens movement amount is set and the follow-up correction flag is reset (# 425, # 445). On the other hand, if the correction amount WR is less than AX, the non-update flag is reset, the tracking correction flag is set (# 417 to # 419), and the routine proceeds to step # 300.

In step # 295, if the defocus amount Δε1 is not within the in-focus zone, the process proceeds to step # 300 and the in-focus flag (focus F) indicating the in-focus state is reset. Next, the current defocus pulse number ERR is set as the previous defocus pulse number LERR, and the current defocus direction (TD)
Is the previous direction (LD) (# 300, # 305). And
It is determined whether or not the tracking correction flag (following correction F) is set. When it is set, the tracking correction amount 2WR is added to the defocus pulse number ERR to obtain a new defocus amount, and step # 335 is performed. Go forward (# 315, # 320).

If the follow-up flag (follow-up F) is set in step # 325, the process proceeds to the subroutine of operation III shown in FIG. In the subroutine of the operation III, first, it is determined whether the mode is the AF priority mode.
150 (msec), Td = 100 (ms in release priority mode
ec) and proceed to step # 2215. This Td is provided to drive the lens by a corresponding amount when the release button is pushed down to the second stroke and the lens drive amount is not 0 (in focus) when the release is possible. , Td = Release time lag (50msec) + TC (constant time). The release time lag is a value determined by the camera. On the other hand, TC is set to 100 msec in the AF priority mode and 50 msec in the release priority mode.

The reason that this value TC is changed in each mode is generally AF
Since the priority mode is a mode used when it is desired to accurately focus on the subject, it is desirable to move the lens as much as possible so that the defocus amount becomes zero. Because it is. On the other hand, in the release priority mode, it is important that the release is made at the moment when the user wants to take a picture anyway, so the fixed time is shortened. Next step #
In 2215, the integration period TI is read and Td is divided by this time TI to obtain this ratio R, and the correction amount WR is multiplied by R in order to obtain the amount of movement WS of the subject moving between Td on the image plane (# 2215). , # 2
220). Then, the defocus pulse number ERR is added to this value WS.
And newly obtain the defocus pulse number ERRT (#
2225). Next, it is determined whether the camera is in the AF priority mode.In the AF priority mode, it is determined whether the number of defocus pulses ERRT is 148 or less and in the release priority mode, it is 100 or less. If there is, in the following mode, a following focus flag (following focus F) indicating that the in-focus state has been reached is set, and if it exceeds the set value, the following focus flag is reset and the routine returns. The above set values will be described in a release mode described later.

Then, the flow returns to step # 340 in FIG. 6, and it is determined whether or not the subject is within the following focusing zone by setting the above-mentioned following focusing flag. If within this zone, the flag AFEF indicating the end of focus detection is set. Then, the in-focus display is performed, and the flow proceeds to the flow of TINNZ (# 335 to # 350). If the tracking flag (following F) is not set in step # 335, or if the tracking flag is set but is not within the tracking focus zone in step # 340, the process proceeds to step # 355, and the defocus pulse number ERRT is set to a narrow value to be described later. It is determined whether it is within the focusing zone (# 355). If it is in the narrow focus zone, the narrow focus flag (narrow focus flag) is set and the process proceeds to step # 365. If it is not in the narrow focus zone, step # 360 is skipped and the process proceeds to step # 365. In step # 365, it is determined whether or not the defocus pulse number ERRT is within the display focusing zone described later. , If not within the display focus zone, proceed to TINNZ without displaying. Here, the focusing zone will be described.

(1) Focusing zone (# 295) In a conventional area, if the driving amount of the lens required to reach the in-focus state once becomes 0 and the integration result in a state where the lens is stopped is this area, Indicates that the camera is in focus.

(2) Display focusing zone (# 365) It is wider than the focusing zone of (1) and is a range in which the lens can be accurately moved to the above focusing zone during the release time lag after release. In this embodiment, , Number of pulses
Defocus amount equivalent to 21 (depends on lens)
And Then, regardless of whether the lens is stopped or moving, if the defocus amount falls within this range, display is performed and release permission in the AF priority mode is performed.

(3) Tracking Focus Zone (Step # 340) The zone is the widest and indicates the range in which the focus display in the tracking mode and the release permission in the AF priority mode are performed. In the tracking mode, when the camera continues to follow the movement of the subject while driving the lens, the focusing state (the defocus amount is 0) may not be achieved. However, in the conventional AF priority mode, the shutter cannot be released without stopping the lens. This tracking focus zone is provided to prevent this, and the size of this zone is set to a value that allows the lens to be driven within a release time lag + a fixed time. This value will be described in detail later in the description of the release flow.

(4) Narrow focusing zone (# 355) This zone is almost the same as the focusing zone of (1).
The reason why this zone is provided is described below. When the lens is driven in this zone, the movement amount CTC of the lens that moves from the integration center to the end of the calculation is subtracted from the number of defocus pulses. Now, the number of defocus pulses is a value at the center of integration. However, the number of defocus pulses may not always be a value at the center of integration due to a change in light, hand shake, or electrical noise. Therefore, the correct defocus amount may not be obtained even if the lens movement amount is subtracted from this defocus pulse number.
Even if the lens is driven and stopped by this defocus amount, the focusing state may not be achieved. In such a case, the lens must be moved again according to the result of the next focus detection. If a similar event occurs during this driving, the lens must be driven based on the result of the next focus detection. This zone is provided to prevent the lens from being stopped due to the detection of the in-focus state forever. Therefore, when the defocus amount falls within this narrow focus zone, focus detection is not performed, and the lens is driven until the defocus pulse number becomes zero.

On the other hand, in FIG. 2, when the lens is not stopped in step # 235, the flow proceeds to the IDOBUN flow shown in FIG.

In the flow of IDOBUN in FIG. 8, first, it is determined whether or not the currently calculated defocus direction is different from the previously calculated defocus direction (# 435). If the direction is reversed, the lens is stopped (step # 455), and the flow returns to the CDINT flow after step # 55 in FIG. 2 in order to perform integration again. On the other hand, if the direction is not reversed in step # 435 in FIG. 8, the movement amount CTC of the lens that has moved from the center of integration to the end of calculation is obtained (# 435, # 440). Next, the procedure proceeds to a subroutine for determining near zone A, which will be described later.
If is set, the process proceeds to step # 460, and if not set, the follow-up flag is reset in step # 520 (# 445, # 450). In step # 460 and below, it is determined whether or not the previously calculated defocus direction (LD) and the currently calculated defocus direction (TD) are in the same direction. The driving amount ITI of the lens moved from the previous integration center to the current integration center is added to the pulse number ERR, and the previous defocus amount LERR is subtracted to obtain the correction amount WR (# 460 to # 470,
# 515).

Next, it is determined whether or not the follow-up flag (following F) is set. When the follow-up flag is not set and the correction amount WR is equal to or larger than the predetermined amount AA, the follow-up flag (following F) and the follow-up correction are performed. The flags (following correction F) are set respectively, and the process proceeds to step # 300 in FIG. 6 (# 480 to # 49).
0).

On the other hand, if the correction amount WR is less than the predetermined amount AA in step # 480, the tracking correction flag (following correction F) is reset, and
The process proceeds to step # 300 (# 480, # 485). Step # 475
When the follow-up flag (follow-up F) is set, the correction amount WR is equal to the predetermined amount AX (count value of the near zone counter).
(Larger than NZC) or more, and if it is more than a predetermined amount, it is determined that the subject has deviated from the focus detection area,
The non-update flag (non-update F) for prohibiting the update of the drive amount of the lens is set, the follow-up correction flag (following correction F) is reset, and the process proceeds to step # 300 (# 500, # 505, # 490).

Conversely, if the correction amount WR is less than the predetermined amount AX in step # 500, the non-update flag (non-update F) is reset, the follow-up correction flag (follow-up correction F) is set, and the process proceeds to step # 300 (# 500). , # 510, # 490).

Returning to FIG. 2, when it is determined in step # 185 that focus detection is impossible, the flow proceeds to the LOWCON flow of FIG. In the LOWCON flow of Fig. 9, the microcomputer (1)
First, it is determined whether or not the follow-up flag (following F) is set. If the follow-up flag (following F) is set, the non-update flag (non-update F) is set (# 52).
0, # 525). Then, it is determined whether or not the flag FIF indicating that this is the first time to pass here is set, and when it is not set, that is, when this is the first time to pass here, this flag FIF is set. The variable N1 is set to 0, and the process proceeds to the CDINT flow of step # 55 and subsequent steps in FIG. 2 (# 5).
30, # 625, # 630).

In step # 530, when the flag FIF is set, 1 is added to the variable N1, and it is determined whether or not this value N1 is 2. If not, step # 55 in FIG. Proceed to the following flow of CDINT, and if it is 2, the follow-up flag (follow-up F) and the non-update flag (non-update F)
Are reset, and the process proceeds to step # 555 (# 535
~ # 550). Steps # 520- # 550, # 625, # 630 above
Then, if the subject is out of the focus detection area in the follow-up mode, the defocus amount may suddenly increase, or it may be determined that focus detection is impossible. Therefore, measures are taken against this. That is, if the focus can be detected even if the defocus amount suddenly increases, it means that the correction amount WR suddenly increases. In this case, the processing in steps # 500 to # 510 in FIG. doing.
On the other hand, when it is determined in step # 185 in FIG. 2 that focus detection is impossible, the flow proceeds to LOWCON in FIG. And
When it is determined that the focus cannot be detected in the tracking mode, that is, when the subject is out of the focus detection area, the normal focus undetectable process from step # 555 is not performed, and the lens is moved based on the previously calculated defocus amount. I'm going to drive. On the other hand, when the follow-up flag is not set in step # 520, the flag FIF is reset and the process proceeds to step # 555.

In steps # 555 and below, count interrupt, timer interrupt, and ENTEVENT interrupt, which will be described later, are prohibited (# 555 to #).
557). Next, it is detected based on the output of the light receiving element provided near the photodiode of the CCD whether or not the cause of determining that the focus cannot be detected is that the luminance of the subject is too low (low light). If the cause of focus detection failure is this low light, it is detected whether or not the auxiliary light emitting device (13) is mounted in the camera, and when the auxiliary light emitting device (13) is installed, the auxiliary light emitting device (13) is detected. The light emission mode is set and it is determined whether or not the auxiliary light flag (auxiliary light F) is set (# 560 to # 570). When the auxiliary light flag (auxiliary light F) is set in step # 570, that is, when the auxiliary light is emitted but the focus cannot be detected due to the low light, the low-con display indicating the focus detection is disabled. The microcomputer (1) waits for an interrupt in order to stop the focus detection (# 570, # 585, # 590). Conversely, step # 5
If the fill light flag is not set at 70, this flag (fill light F) is set, and the long integration flag (long product F) indicating a mode with a long integration time is set, and the step of FIG. 2 is performed. # 55 and below Flow to CDINT. Step # 5
If it is determined in 55 that it is not low light, or if it is determined in step # 565 that the auxiliary light issuing device (13) is not loaded, low contrast display is performed (# 595). Then, determine the flag LBF indicating the lens retraction mode,
When the flag LBF is not set, the lens extension control command is issued.On the other hand, when the flag LBF is set, the lens extension control command is issued to output the instruction to drive the lens drive motor. The focus detection flow following step # 55 in FIG. 2 proceeds to CDINT to perform focus detection (# 600, # 605, # 610, # 615).

Next, the flow of the lens drive control shown in FIGS. 10 to 13 will be described. First, before that, speed control of the lens driving motor in the embodiment will be described. Motor speed types are outside the near zone (out zone)
There are 5 types: speed in the near zone, three speeds in the near zone, and step drive. Depending on the number of defocus pulses at that time in each of the accuracy priority and speed priority modes in the following mode and non-following mode. Thus, the above five types of lens speed control are performed. These are shown in Table 2 and explained. The rotation speed of the motor is 20,000 rpm.
(Out zone), 5,000rpm (near zone 1), 2,500r
There are five types: pm (near zone 2), 1,000 rpm (near zone 3), and step drive. Of these, the step drive is used only in the non-follow-up mode in which accuracy is prioritized, and the lens control is performed with high accuracy.
The difference in the speed of the lens with respect to the number of defocus pulses in the near zone is faster as the speed up to focusing is required. The higher the speed of the motor, the worse the stopping accuracy of the motor. How these speed controls are performed in the sequence of cameras is described below.

First, the TINNZ flow shown in FIG. 10 will be described. In step # 630, the microcomputer (1) determines whether or not the lens is stopped, and if the lens is not stopped, is a flag (non-update F) indicating that the lens drive amount is not updated set? If it is set, the process proceeds to step # 700 without updating the lens drive amount (# 630, # 635). If the lens is stopped in step # 630, the flow advances to step # 680 to proceed to a near zone determination subroutine for determining whether or not the vehicle is in the near zone. The near zone subroutine will be described with reference to FIG. In step # 2300 of FIG. 11, the microcomputer (1) determines whether or not the follow-up flag (following F) is set, and if it is set, the count value NZC of the counter indicating the near zone range is set to 63. If it is set in the non-following mode (when the follower flag is reset), the count value NZC of the near zone counter is 100 in speed priority mode, and the count value NZC of the near zone counter in precision priority mode. Set to 120 respectively and proceed to step # 2310 (# 2300, # 2305, # 2325 ~
# 2335). In step # 2310, the number of defocus pulses
Near zone counter value NZC set by ERR
If it is less than or equal to the count value NZC of the near zone counter, the flag NZF indicating the near zone is set, and if it is equal to or more than the count value NZC of the near zone counter, the near zone flag NZF is reset. Return (# 2310 to # 2320).

Then, returning to step # 685 in FIG. 10, it is determined whether or not the near zone flag NZF is set. If not, a value obtained by subtracting the count value NZC of the near zone counter from the defocus pulse number ERR Into the event counter EVENTCNT (# 685 to # 69)
0). This event counter EVENTCNT subtracts 1 each time a pulse is sent from the encoder (11) in Fig. 1 and executes an interrupt (INTEVENT) indicating the entry of the near zone when the counter content becomes 0. belongs to. When the input to the event counter EVENTCNT is completed, the process proceeds to the event counter set (EVENTCNT set) subroutine in step # 695, and when this subroutine is completed, the process proceeds to step # 700. Call this subroutine the 10th
The description is shown at the upper right of the figure.

In this subroutine (EVNTCNT set), the interrupt (INTEVENT) by the event counter is permitted, and further timer interrupt and counter interrupt (CNTR interrupt) described later are prohibited and the process returns (# 2350 to # 2360).

In step # 635 of FIG. 10, when the non-update flag (non-update F) is not set, the movement amount CTC of the lens moved from the integration center to the end of the calculation is subtracted from the defocus pulse number ERR to actually The number of defocus pulses to be driven is set, and the process proceeds to the near zone determination subroutine shown in FIG. 11 (# 645, # 650). When the flag NZF indicating the near zone is not set in this subroutine, the count value NZC of the near zone counter is subtracted from the defocus pulse number ERR and the count value of the event counter EVENTCNT is set to the event counter set (EVENTCNT set) subroutine. , Go to step # 700 via this subroutine (# 655, # 670,
# 675). When the near zone flag NZF is set in step # 655 or step # 685, the defocus pulse number ERR is set to the drive counter ENZCNT.
, And proceeds to the timer I set subroutine shown in FIG. 14. After the subroutine ends, the process proceeds to step # 700 (# 660, # 665). In this subroutine, the motor speed with respect to the number of defocus pulses in the near zone is determined for each of the modes shown in Table 2 (tracking mode, speed priority in non-tracking mode, and precision priority). The speed control of the motor in the present embodiment is performed by turning on / off the energization of the motor depending on whether or not a pulse is transmitted from the encoder within a predetermined time, thereby keeping the motor speed constant, and changing the predetermined time. Changes the speed of the motor. The shorter the predetermined time, the higher the speed of the motor. The timer equivalent to 5000 revolutions per minute is A1, the timer equivalent to 2500 revolutions is A2, the timer equivalent to 1000 revolutions is A3, and A1 <A2 <A3 The relationship is

The details of the timer I set subroutine shown in step # 665 of FIG. 10 will be described with reference to FIG. 14. In steps # 2400 to # 2455, the motor speed is set so as to be as shown in Table 2. The set timer is set, and in steps # 2460 and # 2465, the count interruption and the timer interruption are permitted, respectively, and the routine returns. Where a ₂
= 61, a ₃ = 30, b ₁ = 31, b ₂ = 15, c ₁ = 79, c ₂ = 31. Flag indicating step drive mode in step # 2435
If STEPF is set, the process proceeds to step # 2470.
In step # 2470, it is determined whether or not the motor drive is stopped, and if it is not stopped, the step drive flag ST indicating that the count interrupt by the encoder pulse has been performed with the value of the drive counter that should perform step drive
Judge whether PDRF is set and set this flag STPDRF
Is set, this flag STPDRF is reset and the timer is set to D1 (# 2470 to # 248
Five). On the other hand, if the motor is stopped or the step drive flag STPDRF is not set, this flag
Set STPDRF and set D2 to the timer (# 24
70, # 2475, # 2490, 2495). The driving time at this time is shorter and D1 <D2.

Returning to FIG. 10, the motor is driven in step # 700. Then, it is determined whether or not the near zone flag NZF is set, and if not set, the moving integration flag NIDF indicating that the integration is performed while moving the lens is set (# 705, # 745). Next, it is determined whether or not the motor is stopped. If the motor is stopped, wait for the motor startup time and proceed to step # 735. If not stopped, immediately proceed to step # 735 (# 750, # 7
55). In step # 735, it is determined whether or not the defocus pulse number ERR has entered the narrow focus zone, and if it is within the narrow focus zone, the microcomputer (to move the lens by the remaining defocus amount without performing integration). In 1), the control waits for interruption, and if it is not the narrow focus zone, step # 55 in FIG.
Go to the focus detection flow CDINT below (# 735, # 740).
If the near zone flag NZF is set in step # 705, the flow proceeds to WNZ3. First, it is determined whether or not the moving integral flag (NIDF) is set. If not, the process proceeds to step # 735. Go forward (# 710). on the other hand,
If the moving integration flag (NIDF) is set in step # 710, the process proceeds to a near zone 3 determination subroutine for determining whether the count value ENZCNT of the drive counter is within the defocus pulse number of near zone 3 (see Table 2).

The details of the sub-zone 3 determination subroutine are shown in FIG. 15 and explained. First, it is determined whether or not the follow-up flag (following F) is set, and when this flag (following F) is set, Count value of drive counter
If ENZCNT is 15 or less, set the flag NZ3F indicating that it is within the near zone 3 and return. If ENZCNT exceeds 15, reset the flag NZ3F and return (#
2500 to # 2510, # 2535). Conversely, in the non-following mode and the speed priority mode, if the count value ENZCNT of the drive counter is 30 or less, set the flange NZ3F and set 30
If it exceeds, reset and return. Further, when the non-following mode is the accuracy priority mode, the flag NZ3F is set when the count value ENZCNT of the drive counter is 31 or less, and when the count value exceeds 31, the flag NZ3F is reset and the process returns.

Returning to FIG. 10, when the near-zone 3 flag NZ3F is not set in step # 715, that is, when the near-zone 3 area is not set, the process returns to step # 712, where the near-zone 3 area is set and the flag NZ3F is set. Resets the moving integration flag NIDF (#
720). Next, when it is determined whether or not the follow-up flag (following F) is set, or when the follow-up flag (following F) is not set and the speed priority mode is set, the process proceeds to step # 735. Go forward (# 725,
# 727). If the mode is the accuracy priority mode, step # 727 is repeated until the lens stops (until the count value ENZCNT of the drive counter becomes 0). This is because the step integration in the accuracy priority mode cannot perform the moving integration correctly because the speed is not constant.

The above-described movement integration will be described with reference to FIG.
FIG. 21 shows the rotation speed of the motor on the vertical axis and the time on the horizontal axis. The upper part shows whether or not the moving integral is possible depending on the state of the motor. In this example, 20,0
Moving integration is prohibited until stepping into near zone 3 during deceleration from 00 rpm, during step drive, and during acceleration from motor stop to 20,000 rpm. This is because during these periods acceleration and deceleration are not always constant, so that the center of integration during movement is not clear, and it is considered that there are many errors in focus detection. On the other hand, when accelerating into or near the near zone, the focus detection error is about a few pulses in terms of the encoder pulse due to the originally low speed of the motor and the short time during acceleration. Integrating is not practical. Therefore, in this embodiment, the time required for the focus adjustment is shortened as much as possible by performing the movement integration as described above.

Next, returning to FIG. 10, the event count interrupt INTEVENT shown in the lower right will be described. Event counter (EVENCN
T) subtracts 1 from the count value each time a pulse comes from the encoder (11). When the count value of the event counter becomes 0, the flow enters this interrupt INTEVENT. In this flow, first, INTEVE in step # 2550
Disables NT interrupts and releases RESF flag
If this flag RESF is set, 40 is added to the count value of the drive counter EVENCNT, and the process proceeds to a timer R set subroutine to be described later to control the rotation speed of the motor (# 2550, # 2555, # 2570, # 2575). If the flag RESF is not set in step # 2555 and the shutter is not being released, the count value of the near zone counter NZC is added to the count value of the drive counter ENZCNT, and the process proceeds to a timer I set subroutine described later. Then, the near zone flag NZF is set, and the flow proceeds to the flow of WNZ3 following step # 710 (# 2560 to # 2567).

Next, the counter interrupt (CNTR interrupt) shown in FIG. 12 will be described. This counter interrupt is controlled by the encoder (1
Executed every time a pulse is generated from 1). When entering this flow, the microcomputer (1) first sets the drive counter EVEN
The count value of CNT is decremented by one, and it is determined whether the count value of the drive counter ENZCNT has become 0 (# 800 to # 8)
05). And the count value of the drive counter EVENCNT is 0
If not, it is determined whether or not the step mode flag STEPF indicating the step drive is set (# 815), and if it is set, the process proceeds to step # 835. If the flag STEPF is not set in step # 815, the process proceeds to step # 820. If the count value of the drive counter ENZCNT exceeds 6 even in the precision priority mode, the step drive is not performed. As a matter of fact, proceed to step # 840. Here, a flag TIPASF indicating that a timer interrupt has been entered before this counter interrupt
Is set, and if it is set, it is reset and the process returns. If the flag TIPASF is not set, the motor is turned off (# 845). On the other hand, in step # 820, the accuracy priority mode is set, and the count value of the drive counter ENZCNT is 6
In the following cases, the process proceeds from step # 825 to step # 830, the flag STEPF indicating the step mode is set, the step drive flag STPDRF is further set, and then the motor is turned off in step # 845 (# 830, # 835 , # 84
Five). Next, it is determined whether or not the flag RESF indicating the release is set, and when it is set, the routine proceeds to the timer R setting subroutine, and when it is not set, the timer I setting subroutine is proceeded to.
After the end of the subroutine, the program returns (# 850 to # 860).
The timer R set will be described at the time of release.

In step # 805, when the count value of the drive counter ENZCNT becomes 0, that is, when the lens finishes driving to the in-focus point, the motor is stopped, the step mode flag STEPF is reset, and the timer interrupt and count interrupt are reset. Prohibit inclusion (# 870- # 880). When the release flag RESF is set, the process returns. When the release flag RESF is not set, the process proceeds to the DRVED flow described later (# 885).

In the DRVED flow, first, a flag 1STDF indicating that the flow has passed once when the count value of the drive counter ENZCNT becomes 0 in the one-shot mode
Is set, and if it is set, the focus detection flow CD from the second step # 55 onwards
Proceed to INT (# 895). This flag 1STDF in step # 895
If is not set, the process proceeds to step # 900, it is determined from the state of the switch (S4) whether the continuous mode is the one-shot mode, and if it is the one-shot mode, the focus flag is set, and this flow The flag 1STDF indicating that the light beam has passed once is set, and the flow proceeds to the focus detection flow CDINT (# 900, # 910, # 915). Step #
If the mode is 900 and it is in continuous mode, it is judged whether the tracking flag is set or not. If it is not set, the flow advances to the INFZ flow from step # 260 onward in FIG. 6 to control the focus display and the like (# 905).

Figure 13 shows the timer interrupt flow. This timer interrupt is executed when no pulse is sent from the encoder within the time set in the timer 1 set routine. In FIG. 13, the microcomputer (1) determines a flag RESF in step # 950 and determines whether or not this timer interrupt has been performed during the release. If it is during release, the flow proceeds to a timer R set subroutine described below (# 950 to # 960). Next, the flag STEPF is determined to determine whether the mode is the step mode. If the mode is not the step mode, the flag TI indicating that the timer interrupt has been performed is determined.
Set PASF, energize the motor and return (#
965 to # 975). When in the step mode, it is determined whether or not the flag STPDRF indicating step driving is set, and if it is set, the motor is energized. Return (# 975, # 980, # 985).

When the release button is pushed down to the second stroke and the release switch (S2) is turned on while the above focus detection and focus adjustment are being performed, a signal that changes from “H” to “L” is output by the microcomputer (1 ) Terminal (INT2)
The release interrupt flow shown in FIG. 16A is executed. First, the microcomputer (1) determines whether or not film winding is completed, and if completed, inhibits the release interrupt and the AFS interrupt from step # 45 in FIG. 2 (a), respectively. Then, a release flag RESF indicating the release mode is set (# 1000 to # 1012).

If the winding of the film has not been completed in step # 1000, it is determined whether or not the release switch (S2) has been turned ON. When S2) is OFF, the flow proceeds to the CDINT flow from step # 55 in FIG.

If the release flag RESF is set in step # 1012, then in step # 1014 the interrupt INTEVENT for entering from the out zone to the near zone is prohibited, and step # 10
At 16, it is determined whether the near zone flag NZF is set. If the near zone flag is not set in step # 1016, the value is not set in the drive counter, so the value obtained by adding the count value NZC of the near zone counter to the count value of the event counter EVENTCNT is counted by the drive counter. Step as value ENZCNT #
Continue to 1025. In step # 1025, the state of the switch (S6) is detected to determine whether or not the mode is the AF priority mode. If the mode is the AF priority mode, the process proceeds to step # 1110. If the mode is the release priority mode, the process proceeds to step # 1030.

To begin with the description of the release priority mode, first, it is determined whether or not the following mode is set, based on whether a following flag (following F) is set. In this calculation I subroutine, the release time lag (switch S2)
The amount of defocus amount is estimated as the amount of movement of the subject during the period from when the exposure is turned on until the actual exposure starts), and this amount is added to the amount of defocus until this mode (release) is entered. Are seeking. This subroutine is shown and described in FIG.

In the subroutine of the calculation I shown in FIG. 17, the movement of the subject during one cycle of the focus detection time, that is, the movement inclination (in terms of defocus amount) of the subject in the unit focus detection time in the optical axis direction is obtained. The moving amount (in terms of defocus amount) of the moving subject is obtained. That is, in step # 2600, the release time lag time RST is divided by the unit focus detection time TI to obtain the ratio R, and the object movement amount WR in the unit time is multiplied by this ratio R to obtain the movement amount WS during the release time lag. Drive this counter ENZCNT
In addition to the count value of, the count value of the new drive counter ENZCNT is obtained and the process returns (# 2600 to # 2610).

Returning to FIG. 16 (a), when it is not in the follow-up mode in step # 1030, the subroutine of the operation I is skipped and the process proceeds to step # 1036. Then, it is determined whether or not the count value of the drive counter ENZCNT is 3 or less. If it is 3 or less, it is determined to be in focus, the motor is stopped, the process proceeds to step # 1190, and if it exceeds 3, the process proceeds to step # 1140. Go forward (# 113
6, # 1137). The flow from step # 1140 onward described below is to drive the lens during the release time lag when the release is permitted. Step #
In 1040, it is determined whether the count value of the drive counter ENZCNT is 13 or less, and if it is 13 or less, the flag e1F that sets the motor speed to 1000 rpm is set and the timer R described later is set.
Proceed to the set subroutine (# 1080, # 1090). If the count value of the drive counter ENZCNT is larger than 13 and equal to or smaller than 40, the process proceeds to the timer R set subroutine (# 1045, # 1
090). If the count value of the drive counter ENZCNT is larger than 40 and smaller than 66, the motor speed is set to 5000 rpm
Then, the flag e2F is set to proceed to the timer R setting subroutine (# 1050, # 1085, # 1090).

Here, the timer R setting subroutine shown in FIG. 19 will be described. This is a routine for setting a timer for setting the speed of the motor, like the subroutine for setting one timer. First, in step # 27080, it is determined whether or not the AF priority mode is set, and if it is the AF priority mode, the process proceeds to step # 2785. This will be described later. On the other hand, when the release priority mode is set, it is determined whether or not the flag e1F is set. If it is set, the process proceeds to step # 2760 to set the timer 1 to A3 (1000rp
Then, the timer interrupt and the count interrupt are permitted, and the process returns (# 2765, 2770). 100 rpm in step # 2705
If the setting flag e1F is not set, it is determined in step # 2710 whether or not the 5000 rpm setting flag e2F is set. If it is set, the process proceeds to step # 2800 to stop the motor. It is determined whether or not the flag Fe2F for correcting the amount α1 that is too much is set is set. When this flag Fe2F is set, A1 is set in the timer 1 (corresponding to 5000 rpm) in step # 2830, and the process proceeds to step # 2765. . If the flag Fe2F is not set in step # 2800, step # 2805
Then, this flag Fe2F is set in step # 2810, and this overshoot amount α1 is added to the count value of the drive counter ENZCNT in step # 2810 to make a new count value of the drive counter ENZCNT, and the process proceeds to step # 2830 to set timer 1 to A1 . Explaining the overshoot amount, if the motor is stopped from 1000 rpm, the overshoot amount is negligibly small, but if the motor is stopped from 5000 rpm, the overshoot will be too large. This amount is almost specific to the rotation speed of the motor, and the variation for each lens is small. Therefore, if a certain value α1 is added to the count value of the drive counter ENZCNT, the lens can reach the in-focus position. The motor starts to stop, and the motor can be stopped properly when the lens reaches the focus position.

When both flags e1F and e2F are not set in steps # 2705 and # 2710, it is determined in step # 2745 whether or not the count value 100 of the drive counter ENZCNT is exceeded, and when it is exceeded, from the count value of the drive counter ENZCNT.
Subtract 40 and count value of the event counter EVENTCNT
, Go to the event counter set (EVENTCNT set) subroutine in Figure 10 and return (# 2730,
# 2735).

If the count value of the drive counter ENZCNT is 100 or less in step # 2745, the process proceeds to step # 2750. Here, it is determined whether the count value of the drive counter ENZCNT is greater than 14, and if it is greater than 14, the process proceeds to step # 2830. Set timer 1 to A1 (equivalent to 5000 rpm) and go to step # 276
Go to 5. In step # 2750, drive counter ENZCNT
If the count value of is less than 14, the process proceeds to step # 2755, and it is determined whether the count value of the drive counter ENZCNT exceeds 4. When the count value of the drive counter ENZCNT is 14 or less and is greater than 4, the timer 1 is set to A2 (corresponding to 2500 rpm) in step # 2850, and when it is 4 or less, the timer 1 is set to A3 (1000 rpm) in step # 2760. ,
Further, in steps # 2765 and # 2770, the timer interrupt and the count interrupt are enabled and the process returns.

Returning to FIG. 16 (a), when the drive counter ENZCNT and the count value exceed 66 in step # 1050,
At 5000 rpm or less, the count value of the drive counter ENZCNT cannot be set to 0 (focus), so the release time lag is increased by a predetermined time (50 msec when not in the AF priority mode in this embodiment) to drive the motor again. I have to. However, in the continuous shooting mode, which represents the continuous shooting mode, the lens is not driven until a predetermined time, which is an increase in the time lag, is provided because it is desired to shoot as soon as possible. Therefore, in step # 1055, the switch (S
The state of 8) is detected to determine whether or not the camera is in the continuous shooting mode. If the camera is in the continuous shooting mode, the process proceeds to step # 1095.
On the other hand, when the mode is not the continuous shooting mode, the process proceeds from the step # 1055 to the step # 1060, and it is determined whether or not the mode is the tracking mode.
In the follow-up mode, the subroutine of calculation II is executed to calculate the movement amount of the subject within the predetermined time set in step # 1065, and then the process proceeds to step # 1070. on the other hand,
If the tracking mode is not set in step # 1060, it is determined that the subject is stopped, and step # 1065 is performed.
Proceeding to step # 1070, the timer is set in the above-described timer R set subroutine in accordance with the count value of the drive counter ENZCNT, and after waiting for 50 msec, the lens is moved. (# 1060 to # 1075).

Next, the subroutine of the operation II in the step # 1065 will be described with reference to FIG. In this subroutine, first
In step # 2650, it is determined whether or not the camera is in the AF priority mode. In the case of the AF priority mode, the time TC is set to 100 msec. In the case of the release priority mode, the time TC is set to 50 msec. The ratio R is obtained by dividing by TI, and in step # 2670, the defocus amount (count WR) of the object moving within the unit focus detection time is multiplied by this ratio R to obtain the tracking delay defocus amount WS until exposure. In step # 2675, WS is added to the count value of the drive counter ENZCNT, a new count value of the drive counter ENZCNT is obtained, and the process returns. In Step # 1095, which was advanced from Steps # 1055, # 1075, and # 1090, the motor speed is low speed (5000 rpm).
It is determined whether or not it is below, and it is not low speed (that is,
At 20,000 rpm), the motor does not stop immediately even if the motor stop signal is output, so the motor brake signal is output (# 1095, # 1100). Then, in steps # 1103 and # 1107, the count interrupt and timer interrupt are prohibited, and the process proceeds to step # 1190. Step #
If the speed is low at 1095, proceed directly to step # 1190. When it is in the AF priority mode in step # 1025, it is determined whether or not the flag AFEF indicating the end of focus detection is set, and if it is not set, the release flag RESF is reset and the process returns (# 1110, # 117).
0).

In this embodiment, even if the focus state is detected again after the exposure is completed, the release button will not be released if it is continuously pressed, and the release button will be released again.Here, in step # 1170, the release flag The RESF is not reset, while the release flag RESF is judged in the step following step # 250, and if set, this step # 11
If you proceed to step 15, you can use the method of releasing immediately after focusing.

If the flag AFEF is set in step # 1110, it is determined in step # 1115 whether or not the mode is the tracking mode. If not, the process proceeds to step # 1190. When in the follow-up mode, the drive counter ENZCNT is calculated by calculating the distance of the moving object during the release time lag in the subroutine of calculation I of step # 1120 (shown in FIG. 17).
If the count value is not more than 13, the flag f1F for controlling the motor at 1000 rpm is set, the flow proceeds to a timer R set subroutine for setting a timer for controlling the speed of the motor, and the flow proceeds to step # 1190 ( # 1120, # 112
5, # 1175, # 1185). Drive counter E in step # 1125
If the count value of NZCNT is 21 or less, step # 1185
The routine proceeds to step # 1190 from the timer R set subroutine. Further, when the count value of the drive counter ENZCNT exceeds 21 in step # 1140, it is determined in step # 1145 whether or not the continuous shooting mode is set, and if the continuous shooting mode is set, the release priority mode is the same as described above. , Shall be taken immediately and proceed to step # 1190. If the continuous shooting mode is not set in step # 1145, it is the AF priority mode, and the lens is always brought to the in-focus position. Therefore, control is performed to move the lens for a predetermined time (100 msec). In other words, the lens is brought to the in-focus position by taking 150 msec together with the release time lag (50 msec). Here, since the mode is the following mode, the process proceeds to the subroutine of the calculation II in step # 1150 to obtain the amount of defocus in which the subject moves during the 100 msec, and the count value of the necessary drive counter ENZCNT is obtained. Then, the process proceeds to a timer R set subroutine to control the speed of the motor based on this value and waits for 100 msec (# 1150 to # 116
Five).

Here, the case of the timer R set in the AF priority mode will be described with reference to FIG. In the case of the AF priority mode, the process proceeds from step # 2780 to step # 2785, and 1000rp
When the flag f1F indicating the m drive is set, the routine proceeds to step # 2760, and the timer 1 is set to A3 (corresponding to 1000 rpm). If the flag f1F is not set in step # 2785, the driving counter EN is set in step # 2790.
It is determined whether the count value of the ZCNT is 28 or less. If the count value is not 28 or less, a time A1 corresponding to 5000 rpm is set in the timer 1. Similarly, if the count value of the drive counter ENZCNT is 8 or less, the process proceeds from step # 2795 to step # 2760 to set the timer 1 to A3 and control the motor to 1000 rpm.
If it is larger than 28, the process proceeds from step # 2795 to step # 2850 to set timer 1 to A2 and set the motor to 2500
Control to rpm.

Table 3 shows the relationship between the number of rotations of the motor and the encoder pulse and the time required for focusing in each of the AF priority mode and the release priority mode.
Is. To briefly explain the relationship between the number of rotations and the pulse of this motor, in AF priority mode, this mode is selected so that the lens is released when the lens is in focus, so it is higher than the release priority mode Focusing accuracy is required, and the use time of 1000 rpm is extended to reduce stop errors due to motor inertia.

In the AF priority mode, a control method that constantly monitors the number of revolutions without adopting 20,000 rpm is used to improve the focusing accuracy.

On the other hand, in the release priority mode, focus detection accuracy is also required, but since exposure is required earlier than that, the setting time of the motor drive during release is shortened compared to the AF priority mode. I have.

Returning to FIG. 16 (a), in step # 1190, the auxiliary light emitting device (13) is turned off, and then the display is turned off (# 11).
90, # 1195). Next, a mirror-up start signal and an aperture control signal are output to the exposure control circuit to control the mirror-up and the aperture to a predetermined value Av, and wait for the mirror-up to be completed (# 1200 to # 1210). During this time, if the mirror up of about 50 msec is completed, a motor stop signal is output,
Wait 10 msec for the motor to stop, prohibit interrupts, output an exposure start signal, and start running one curtain. (# 1215-1230). Then, the exposure time Tv is measured, and when it reaches a predetermined Tv, an exposure end signal is output and the system waits for the closing of two curtains (# 1235 to # 1240).

Next, proceeding to FIG. 6 (b), the microcomputer (1) outputs a one-frame winding start signal in step # 1243 to start film 1
Make the piece roll up. Then, in step # 1245, it is determined whether or not the camera is in the continuous shooting mode. When the camera is not in the continuous shooting mode, the terminal (OP3) is set to "L" so that continuous shooting is not performed, and the process proceeds to step # 1275. On the other hand, in the continuous shooting mode, the terminal (OP3) is set to "H" level in step # 1247, and a timer start signal is output to the timer circuit (15) in FIG. Next, when the focus flag is not set or the focus zone is not entered, enable the counter interrupt and the timer interrupt to drive the motor so that only the remaining count value of the drive counter ENZCNT is driven. Drive and proceed to step # 1275 (# 1250, # 1255, # 1265, # 1270). If AF is completed and focus is achieved during this time, the process returns from step # 885 in FIG. 12 to step # 1275 again to loop step # 1275. When the in-focus flag (in-focus F) is set and is within the in-focus zone, the in-focus display is performed in step # 1260 and then the process proceeds to step # 1275 to wait for the mirror to go down (# 1250 to # 1260). , # 1275).

When the mirror down is completed, a signal to stop the motor for driving the lens is output, and this stops for 20 msec.
After waiting, the flags other than the follow flag are reset, the release interrupt is permitted, and the flow returns to the CDINT flow from step # 55 onward in FIG. 2 (# 1280 to # 1295). However, steps # 1280 and # 1285 are not always necessary here, and the process may return to CDINT with the lens being driven.

In the present embodiment, when the release button is continuously pressed while the continuous shooting mode is set, the terminal (OP3) goes high and the timer circuit (15) starts counting time. At a predetermined time, a signal that changes from "H" level to "L" level is input to the terminal (INT4) of the microcomputer (1). When this is input, the microcomputer (1) again
16 Start the interrupt from step # 1297 in Fig.
In step # 1297, an "L" level signal is output from the terminal (OP3) to stop the timer circuit (15), and thereafter, the release flow operation from step # 1000 is similarly performed.

Next, the flow of the termination interruption shown in FIG. 20 will be described. This is the process flow when scanning at low contrast, when the contrast of the subject is detected while driving the lens, and the end of the lens is reached without detecting a sufficient contrast level for focus detection. It is.
This end is detected by a switch (S
7) is provided, and this switch (S7) is turned on when the lens reaches either the end position of the closest position or the infinity position, and the terminal (INT3) of the microcomputer (1) is set to the “H” level. , The microcomputer (1) performs the flow of the termination interrupt shown in FIG. In this flow, first, the motor is stopped in step # 1350, and it is determined in step # 1355 whether or not the flag LBF for retracting the lens is set. If not set, the lens is extended and the end is reached. So, set this flag LBF in step # 1360 and step # 136
Start the inversion drive at 5 and proceed to the CDINT flow in FIG.
If the flag LBF is set in step # 1355, it means that contrast detection is not possible because the lens has reached the end after making one round trip.
At 70, the microcomputer (1) indicates that it is impossible.

Next, a modified example is shown. The contents of the modified example are as follows.

1) In the release priority mode during release, eliminate 20,000 rpm of the motor and reduce stop error.

2) If the count value of the drive counter ENZCNT does not become 0 within the predetermined time in the AF priority mode during release, release lock is performed.

3) In the AF priority mode and the precision priority mode during release, the motor speed is only 1000 rpm, release is possible only when the count value of the drive counter ENZCNT becomes 0, and release lock is performed when it does not become 0. To increase the focusing accuracy.

 A modified example accompanying the above change is shown and described in FIG.

First, in the change accompanying (1), steps # 1095 to # 1107 in FIG. 16A are deleted. This is 20,000 rpm
This is because (high speed) disappears (see FIG. 22). This and steps # 1745 and # 27 in FIG.
30, # 2735 is deleted, and this is also deleted because the high speed mode is not in the release (not shown). Furthermore, step # 255 in the INTEVENT flow
5, Delete # 2570 and # 2575.

Next, a change associated with (2) is that a drive counter ENZC is provided between step # 1150 and step # 1160 in FIG.
Step # 1155 for determining whether or not the NT count value exceeds 148 is inserted, and if it exceeds 148, step # 1170
And resets the release flag RESF and returns. This value 148 will be explained with reference to Table 3. It takes 60 msec until the number of pulses reaches 28.
90msec after subtracting sec is the time that can be driven at 5000rpm,
The number of pulses that can be driven is 4/3 x 90 = 120.
Add up to 148.

The point to be changed in accordance with (3) is that, after step # 1125 of FIG. 16A, a step of determining whether or not the accuracy priority mode is provided is provided as step # 1130. Proceed to step # 1145 to prohibit modes above 1000 rpm. Also, after step # 1150, step #
A determination step for determining whether or not the mode is the precision priority mode is provided as 1152. When the mode is the precision priority mode, the count value of the drive counter ENZCNT is 40 or less (150 msec × 4/15 (1000r
pm)), a step # 1153 for judging whether or not the flag is f40 is provided.
Then, the process proceeds to step # 1175 to perform the processing thereafter. If it exceeds 40, the release flag RESF is reset in step # 1170 and the routine returns. Step #
If it is not the precision priority mode in 1152, the flow proceeds to step # 1155, and the subsequent steps are performed.

[Advantages of the Invention] As described above, according to the present invention, focus adjustment is performed by predicting the amount of defocus at the start of exposure, so that focus is achieved at the start of exposure even if the subject is moving.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flow chart showing the operation of the apparatus of FIG. 1, FIG. 3 is a graph showing the offset of the event counter of the focus detection apparatus, and FIGS. FIG. 20 is a flow chart showing the operation of the apparatus shown in FIG. 1, FIG. 21 is a time chart showing the relationship between movement integral control and motor drive control, and FIGS. 22 and 23 show modified examples. Flowchart, Figures 24 and 25
The figure shows the principle of focus detection, FIGS. 26 and 27 show the principle of conventional tracking correction, and FIGS. 28 to 31 show the principle of tracking correction applied to the embodiment of the present invention. It is a figure. 1 ... Microcomputer, 2 ... Exposure control circuit, 3 ... Photometric circuit, 10 ... Motor control circuit, 11 ... Encoder, 12 ... Lens internal circuit, 13 ... Auxiliary light generator, 15 ... Timer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Taniguchi 2-30 Azuchi-cho, Higashi-ku, Osaka-shi, Osaka, Osaka, Osaka International Building Minolta Camera Co., Ltd. (72) Hiroshi Otsuka 2-chome, Azuchi-cho, Higashi-ku, Osaka-shi, Osaka No.30 Osaka International Building Minolta Camera Co., Ltd. (56) Reference JP-A-60-214325 (JP, A)

Claims (1)

[Claims] 1. An image pickup device for receiving a subject image and converting it into an electric signal; a first calculation device for calculating a defocus amount from a focus position of the image pickup lens based on an output of the image pickup device; Drive means for driving the exposure control means, signal output means for outputting a start signal for starting the exposure control, and exposure control means for starting the exposure after a predetermined release operation when the start signal is output. In the focus adjustment device, movement detection means for detecting movement of the object in the optical axis direction based on a plurality of defocus amounts obtained by the first calculation means, and release from the time the shutter is released until the actual exposure is started. Output means for outputting a time lag, the movement of the subject detected by the movement detection means,
Second calculating means for predicting and calculating the amount of change in the defocus amount that would occur due to the movement of the subject in the optical axis direction during the release time lag, based on the release time lag output by the output means; Drive control means for controlling the drive means based on the output of the second computing means during the period from the output of the start signal to the start of exposure, and the focus state is set at the timing of the exposure start. Is characterized in that