JPH0792539B2 - Automatic focusing device for camera with zoom lens - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic focusing device for a camera having a zoom lens.

(Prior Art) Recently, with the development of electronics technology, various automatic cameras having an automatic focusing device and a power zoom lens for driving a zooming lens group by a driving means such as a motor have been realized. There is.

Then, in this kind of automatic focusing device, for convenience of determining the composition in the viewfinder, after focusing by the automatic focusing device, if the photometric switch is turned on, after that, it will automatically be released until release processing is performed. Some have a so-called focus lock function that can temporarily stop the operation of the focusing device.

By the way, when a zoom lens is installed in a camera that has an automatic focusing device with such a focus lock function,
It is required that zooming is possible even in the focus locked state.

On the other hand, in the zooming lens group, the object image should be always formed on the film surface within the zooming area, but due to manufacturing reasons, etc., the zooming lens group shifts to the image forming position. There are things that cause.

(Problems to be Solved by the Invention) Therefore, when the power zoom lens is operated after being focused by the automatic focusing device, the focus state is not always kept in focus, and the focus shift when taking a picture as it is There is a risk of taking pictures.

The present invention has been made on the basis of such a background, and an object of the present invention is to prevent an out-of-focus image from being taken even if zooming is performed after focusing once in a camera of this type. It is a thing.

(Means for Solving the Problem) An automatic focusing device for a camera having a zoom lens according to the present invention, in order to achieve the above object, a photographing lens having a focusing lens group and a zooming lens group,
The driving amount of the focusing lens group is calculated from the storage means that stores the unique information of the taking lens and the defocus amount,
It has a driving means for driving the focusing lens group based on the calculation result, and an output means for a focusing operation command for maintaining the state of the focusing lens group as it is after focusing. , This storage means stores the data of the relationship between the focal length of the taking lens and the focus shift, and when the zooming lens group is moved with the output means for the focusing operation command being turned on, the zooming is performed from the storage means. A correction value based on the previous focal length,
Read the correction value based on the focal length after zooming,
The driving means is driven based on the difference between these correction values.

(Operation) Therefore, even if zooming is performed in the focus locked state after focusing, the focus shift amount corresponding to the movement amount of the zooming lens group is read from the storage means, and the focusing lens group is driven based on this. Since the image is corrected and corrected, out-of-focus shooting can be reliably prevented, and the degree of freedom in using the zoom lens is increased when the composition in the viewfinder is determined using the zoom lens. .

(Embodiment) The present invention will be described below with reference to an embodiment of an automatic single-lens reflex camera shown in the drawings. The present invention is a so-called compact camera or still video camera in which a taking lens is integrally installed in a camera body. It goes without saying that the same can be carried out.

The camera body CB of this automatic single-lens reflex camera has a publicly-known structure so that various kinds of photographing lenses as shown in the figure can be exchangeably mounted, and this camera body CB has a power composed of a so-called varifocal lens. A zoom type photographing lens L is attached.

FIG. 1 is a block diagram of a combined system of a taking lens L and a camera body CB according to the present invention.

The camera body CB includes a main CPU 10 for performing various kinds of information processing for photographing, and a display CPU 1 mainly for inputting information by using switches and transmitting / receiving information to / from the photographing lens L.
It is equipped with two CPUs 1 and 1, and an LCD panel 12 that displays various information centered on these CPUs, a DX code input circuit 13 that inputs the ISO sensitivity of the film used from the DX code printed on the Patrone. , A light receiving element 14 for measuring the brightness of a subject from a light flux incident through the taking lens L, an A / D circuit 15 for A / D converting the output of the light receiving element, and a shutter based on various input shooting conditions. An exposure control circuit 16 for controlling, an AF CCD 17 for receiving a subject image formed by a light flux incident through the taking lens L, and this AF
For detecting the focus state of the taking lens L from the output of the CCD 17 for camera C
A CD processing circuit 18 is provided.

An autofocus (AF) motor 19 for focusing the lens calculates the output of the CCD processing circuit 18 to drive the AF motor 19, and detects the drive amount of the AF motor 19 as a pulse. With the AF pulsar 21, the driving force is transmitted to the photographic lens L side via the coupler 19a provided at the mount opening when the conventional type photographic lens L having no AF motor in the lens is mounted. It is not used in the state shown in FIG.

The battery 22 supplies power to each active element in the camera body CB described above, and also supplies power to a motor and a CPU in the photographing lens L described later.

On the other hand, the taking lens L is internally provided with an AF motor 60 (corresponding to the driving means in the present invention) and a power zoom (PZ) motor.
Three motors, 61 and an automatic iris control (AE) motor 62, are built in, and any of auto focus, power zoom, and iris control can be performed by the driving force in the lens.

The photographic lens L has a cam mechanism similar to the conventional one that performs focusing and zooming by relatively moving each lens group in the optical axis direction by rotation of the cam ring.
The AF motor 60 and the PZ motor 61 respectively rotate the cam rings.

Each motor consists of AF motor drive unit 63, PZ motor drive unit 64, AE
It is configured to be controlled by the lens CPU 66 via the motor drive unit 65.

As information input means for the lens CPU 66, a lens ROM 67 (corresponding to the storage means in the present invention, which will be described later) as a storage means for storing information peculiar to the lens, the drive amount of each motor, Includes AF pulsar 68, PZ pulsar 69, AE pulsar 70 for pulse conversion detection, and zoom code plate 71 and distance code plate 72 for detecting the rotational positions of the zooming and focusing cam rings, respectively. is doing.

The code plate is actually composed of a combination of a code plate fixed to the cam ring and a plurality of brushes that are attached to the fixed ring and are in sliding contact with the code plate. However, the term "code plate" is used as a generic term here for the sake of convenience.

The lens CPU 66 is capable of communicating with the camera body CB via an electrical contact group TC described later, in addition to being connected to the above-mentioned controlled object and input means, and is detected on the camera body CB side, for example. The AF amount is calculated by referring to the lens ROM67 data in response to the defocus amount
A function to drive the AF motor 60 while detecting the drive amount by the pulsar 68, or AE while detecting the drive amount by the AE pulsar 70 based on the aperture value determined on the camera body CB side.
It has a function of rotating the motor 62.

At the lens mount opening of the camera body CB, an electrical contact group T1 consisting of 10 electrical contacts is provided while being insulated from the base (see FIG. 2).

On the other hand, the mount portion of the photographing lens L is provided with an electric contact group T2 corresponding to the electric contact group T1 provided on the camera body CB side (see FIG. 3).

When the photographing lens L is mounted on the camera body CB, the electrical contact groups T1 and T2 of the same name contact each other to form the electrical contact group TC.

The system will be described below based on a more detailed circuit diagram.

FIG. 2 shows a circuit of the camera body CB.

The voltage of the battery 22 is supplied to the VDD1 terminal of the display CPU 11 after being transformed by the regulator R and backed up by the supercapacitor 24, and is constantly operating at a constant voltage.

Also, the P1 terminal of the display CPU 11 turns ON / O the power of the main CPU 10.
It is connected to the DC / DC converter 25 that performs FF, and the P2 terminal is a metering switch SW that turns on by pressing the shutter button one step.
The S and P3 terminals are connected to the release switch SW R that turns on when the shutter button is pressed twice, and the P4 terminal is connected to the lock switch SW L that turns on when the camera is in the shooting state, and the data of each switch is input. .

The photometric switch SW S corresponds to a so-called focus lock switch, and corresponds to an output unit of a focusing operation command in the present invention, and is an automatic focusing process in power zoom and focusing priority mode. In this case, by turning on the photometric switch SW S, the state of each lens group at the time of focusing is held and the focus is locked until the shutter is released.

The DC / DC converter 25 has VD of the main CPU 10 when the photometry switch SW S is turned on while the lock switch SW L is turned on.
Operate this by supplying power to the D terminal.

Furthermore, when the P5 terminal is ON, the mode switch SW M that makes it possible to select the shooting mode such as program shooting, automatic shooting, and manual shooting, and when the P6 terminal is ON, it makes it possible to select single shooting, continuous shooting, etc. The switches SWDR, P7 terminals are connected to the exposure compensation switch SWXV that makes it possible to compensate the exposure set when turned on, and these switches connected to P5 to P7 are connected to the P8 terminal with the switches turned on. Each setting can be changed by operating the up-count switch SWUP or the down-count switch SWDN connected to the P9 terminal.

The PSEG terminal group is for driving the LCD panel 12, and displays the information stored when the lock switch SW L is turned on.

The PA contact group of the main CPU 11 is connected to the A / D circuit 15 for photometry, the PB contact group is the exposure circuit 16, the PC contact group is the CCD processing circuit 18, the PD contact group is the AF motor control circuit 20, and the PE contact. The group is connected to the AF pulser 21 and the PF contact group is connected to the DX input circuit 13.

The A / D circuit 15 is connected to the light receiving element 14 for photometry and the CCD
The processing circuit 18 is connected to the CCD 17 for AF, and the AF motor control circuit 2
As described above, 0 is connected to the AF motor 19 in the camera body CB.

In addition, the P20 terminal of the main CPU10 is connected to the first autofocus switch SWAF1 that switches the focusing between the auto mode by driving the AF motor and the manual mode by the user's manual drive, and the P21 terminal is the shutter release mode. Second AF switch SWAF2 to switch between focus priority and release priority
It is connected to the.

FIG. 3 shows a circuit of the taking lens L.

The VBATT contact on the lens side is connected to each motor drive unit 63,6 in the lens.
4 and 65 are connected to each motor 6 from the battery 22 in the camera body CB by switching these drive units.
Directly power 0,61,62.

The motor drive units 63, 64, and 65 are PH and P of the lens CPU66.
It is configured to be connected to and controlled by the I and PJ terminal groups. The pulsars 68, 69, 70 are connected to the P20 to P22 terminals and input the drive amount of each motor detected to the lens CPU 66. It is composed.

The Vdd contact supplies the power supplied from the display CPU 11 on the camera body CB side to the Vdd terminal of the lens CPU 66 and the reset circuit including the resistor R, the diode D and the capacitor C.

The reset circuit has a constant time constant with a resistor and a capacitor, and after the power supply voltage is stabilized for a certain time after Vdd is turned on, the ▲ ▼ terminal of the lens CPU 66 is changed from active (L) to non-active (H). It has a function to switch to and start the lens CPU66 program.

The P23 to P27 terminals of the lens CPU66 are provided on the lens side and are provided with a third autofocus switch SWAF3 for switching between automatic and manual autofocus, and a zoom switch SWPZ1 for selecting whether to perform zooming automatically by a motor or manually. , A constant image magnification switch SWPZ2 that automatically performs zooming along with relative movement with the subject so as to maintain the image magnification of the subject, PZ to move the lens in the direction in which the focal length of the taking lens L becomes longer.
A Tele-side zoom switch SWPZT for driving the motor 69 and a Wide-side zoom switch SWPZW for driving the PZ motor so as to move the lens in the direction of decreasing the focal length are connected.

The lens CPU 66 has an INT terminal to which an electric signal for interrupting the program execution of this CPU is input, an SCK terminal to which the serial clock from the camera CPU CB side display CPU 11 is input, and an SI for serially transferring data. It has a / SO terminal and a ▲ ▼ terminal for synchronizing the serial communication of the lens CPU 66 with peripheral devices.

The INT terminal enables interrupts of the lens CPU 66 by L → H after ▲ ▼, and the ▲ ▼ terminal makes the display CPU 11 on the camera body CB side stand by so that serial communication is not executed by H, and serial communication is possible by L. To do.

In addition, the lens CPU67 PK terminal group has a lens ROM67 P
Like the L and PM terminal groups, the zoom code plate 71 and the distance code plate 72 are connected, and the focal length information and the distance information corresponding to the actual lens state are input.

The lens ROM 67 is the unique information of the taking lens L,
For example, unique information such as the maximum aperture F-number, the minimum aperture F-number, the amount of change in the F-number due to zooming, and variable information are stored.

In this embodiment, as will be described below, correction data, which is an eigenvalue of the taking lens L, is stored in the lens ROM 67.

That is, this correction data represents the amount of focus shift when the zooming lens group of the taking lens L is driven to a certain focal length, as the number of pulses to be moved by the focusing lens group, For example, when the taking lens L is a varifocal lens having a focal length of 70 mm to 210 mm, it is as shown in Table 1 below.

The number of correction pulses varies depending on the lens design and which one of n1 to n10 is set to 0.

And the information stored in this lens ROM67 is
Data is transferred to the CPU on the camera body side via the electrical contact group TC in response to a request from the CPU on the camera body CB side or directly from the PU 66.

In the camera system configured as described above and having the above-described function, the first autofocus switch is provided.
SWAF1 is turned on and the second autofocus switch SWAF2
When the focus priority mode is selected by, and when the power zoom mode is selected by the zoom switch SWPZ1 and the focus is achieved, the Tele side zoom switch SWPZ is selected.
When the zoom lens group is driven by the T or Wide side zoom switch SWPZW, the correction operation is performed according to the flowchart described below.

The flow charts shown in FIGS. 4 to 15 will be described below.

The main program for automatic focusing will be described below with reference to the flowchart shown in FIG.

In the program below, the photometering switch SW S is turned on while the lock switch SW L is turned on, and the DC / DC converter 2
It starts when power is supplied from 5.

In this way, when starting, the subroutine of initialization is first executed in S.1, and the process proceeds to S.2. Although the timer interrupt can be performed by the initialization, the contents of the initialization subroutine will be described later with reference to FIG.

In S.2, it is determined whether or not the AF mode switch (FIG. 3, autofocus switch SWAF3) is input to enter the AF mode. This is because when the AF mode is not set, the process according to this flowchart is excluded, and such a case is excluded.

Therefore, if it is the AF mode, the process proceeds to S.3, but if it is the manual mode other than the AF mode, it is performed by the manual mode processing and the automatic focusing is not performed (M in the fourth illustration).

In S.3, it is determined whether or not the manual focus is being performed. MF indicates a flag during manual focus. When this flag MF = 1, it indicates that manual focus is in progress, and when MF = 0, it indicates that manual focus is not in progress. Therefore, in the case of YES, it means that the user has selected the manual focus even in the AF mode. Therefore, as in the case of S.2, the processing according to this flowchart is not applicable.
It goes through the processing mode and returns to S.2 to enter the manual mode (K in the fourth diagram).

That is, in the present embodiment, the switch for switching between auto focus and manual focus is provided not only on the lens side (SWAF3) but also on the camera side (SWAF1), and AF operation is performed on condition that both of them are in the AF mode. It will be possible.

If NO, proceed to S. 4 to determine whether or not the photometric switch SW S is turned on. If YES, add a flag mark indicating that the AF mode is in S. 5 and start AF operation. .

If NO in S.4, the user's willingness to shoot is not confirmed. Therefore, the process returns to S.2 and S.2-4
Wait for the metering switch SW S to be turned on.

When the AF operation is started in S. 5, the defocus amount dx detected by the detection device such as the CCD 17 for AF is calculated in S. 6, and the S.
In step 7, it is judged whether the contrast of the signal detected by the CCD 17 is low.

In the case of YES, it is difficult to focus with CCD 17, so S. 2
Return to S. 2 to 7 and wait until the contrast is restored or the manual mode is selected.

In the case of NO, it is determined in S.8 whether or not the focus state is achieved.

If it is not in focus as it is, it is judged as NO, proceed to S. 9 to 11, put a flag mark to prohibit the operation of the release switch SW R, turn off the focus display,
Driving amount of focusing lens group from defocus amount dx
Calculate dP.

On the other hand, in S.8, if it is determined that the subject is in focus as it is, the process proceeds to S.12 to 16. MAGIMG is a flag for starting constant image magnification control. When MAGIMG = 1, constant image magnification control is started, and when MAGIMG = 0, constant image magnification control is not performed. In S.12, it is determined whether or not the flag MAGIMG for starting the constant image magnification control is set, and when the constant image magnification control mode is not selected, the normal operation processing is performed. That is, in the case of NO, the focus indicator is turned on, a flag mark permitting the operation of the release switch SW R is attached, and the process proceeds to S. 15. Therefore, after S. 14, release processing by timer interrupt processing becomes possible.

On the other hand, if YES in S. 12, the focus display is turned off in S. 16 and the image magnification constant control mode is entered (B). This process B is
It is started by turning on the SWPZ2, and it calculates the amount of extension of the focusing lens group, inputs the current focal length information of the zooming lens group, calculates the defocus amount, calculates the drive amount of the focusing lens group, etc. Arithmetic processing is performed. by this,
As described above, zooming is automatically performed as the subject moves relative to the camera, and the image magnification of the subject is maintained regardless of the change in the distance between the subject and the camera. The process B is described in detail in Japanese Patent Publication No. 7-13697 by the applicant of the present application.

In S.15, it is determined whether or not the focus priority mode is set, and if YES, the process is repeated to perform focus lock, and if NO, the process returns to S.2 (A).

On the other hand, as described above, if NO is determined in S.8 and the driving amount dP of the focusing lens group is calculated, then in S.17, the driving direction of the focusing lens group is determined from the signal of the detection means. , S when the driving direction is Near.
In step 18, it is determined whether or not the focusing lens group exists at the Near end, and in the case of the Far side, in S. 19, it is determined whether or not the focusing lens group exists at the Far end.

Then, if YES is determined in these S. 18, 19, AF processing in the macro area is started by I.

If NO in these S. 18, 19, S. 2
Subroutine for moving the focusing lens group to the end point on the driving direction side at 0 or S. 21 (see FIG. 11, FIG.
(See Fig. 12), and proceed to S. 22 for both.

In S.22, the driving amount of the focusing lens group dP
Drive is judged to have ended, and if NO, in S.23.
It is judged whether the AF pulser 68 pulse output interval is 100 msec or longer.If it is 100 msec or longer, it is considered that the focusing lens group has reached the end point.
Execute the AF end point processing subroutine (see Fig. 13) and execute S.
Return to 2.

If it is less than 100 msec, return to S.22 and drive amount d
Cycle through S.22 and 23 and wait until the end of P or the output interval of the AF pulsar 68 reaches 100 msec.

On the other hand, when the drive amount dP of the focusing lens group is finished driving in S. 22 and YES is determined, the process proceeds to S. 25 and the AF driving is stopped (described later in FIG. 14).
To return to S.2, S.2-8 and S.12
If focus is achieved at ~ 16, release processing becomes possible. If focus is not achieved, steps S.2-11 and S.17-25 are circulated.

From such AF processing, by timer interrupt processing,
The power zoom drive check process shown in FIG. 5 and FIG. 6 is performed, and after this power zoom drive check process, the release process is performed by the timer interrupt process.

Next, a flowchart regarding the power zoom drive check will be described with reference to FIGS.

In the power zoom drive check process, it is determined in S. 101 whether or not the power zoom mode is set. If YES is determined in the power zoom mode, the image magnification constant control is performed in S. 102 and S. 103. It is determined whether or not it is in the middle and whether or not it is the power zoom drive for AF in the macro area.

ONIMG is a flag indicating whether or not constant image magnification control is being performed. When ONIMG = 1, it means that constant image magnification control is being performed, and when ONIMG = 0, it means that constant image magnification control is not being performed. In the present embodiment, the manual power zoom can be performed by manual operation, but the provision of this step S102 prevents the manual power zoom process from entering during the constant image magnification control. .

If YES is determined in S. 102 and S. 103, the process is not processed and the process returns.If NO is determined in S. 104, the wide side zoom switch SW PZW is turned on / off. to decide.

If it is determined that the Wide zoom switch is on, S. 10
In step 5, it is determined whether or not the zooming lens group is being driven. If YES, in step S. 106 it is determined whether or not the driving direction of the zooming lens group is the Tele direction.

On the other hand, when it is determined in S. 104 that the Wide side zoom switch is off, in S. 107 to 109, the same determination as in S. 104 to 106 is made for the Tele side zoom switch SWPZT.

Then, in S. 104 to 106 and S. 107 to 109, when one of the power zoom switches is turned on and the zooming lens group is driven in the same direction as the turned on power zoom switch, In 110, it is judged whether the output interval of the zoom pulse of the PZ pulsar 69 is 100 msec or more.

If it is less than 100 msec, the zooming lens group is in motion, so it returns, and if it is longer than that, it is considered that the zooming lens group has reached the end point.
In step 111, the zoom stop subroutine (see Fig. 10) is executed. In step S. 112, it is determined whether or not the zooming lens group has been driven toward the Tele end. If YES, step S. 113
Then, a flag mark indicating that the zooming lens group exists at the Tele end, and in the case of NO, a flag mark indicating that the zooming lens group exists at the Wide end are attached at S. 114, and the process proceeds to S. 117.

On the other hand, in S. 101, if it is determined to be NO instead of the power zoom mode, in S. 104 and S. 107.
When both Tele and Wide power zoom switches are turned off, proceed to S. 115, S. 1
In step 15, it is judged whether or not the power zoom is in operation. If NO, the process returns. If it is YES, the zoom stop subroutine (Fig. 10) is executed in step S.116, and then step S.117 is executed.
I will proceed.

In response to these S. 113, 114, and 116, in S. 117 to 119, it is sequentially determined whether or not AF is in progress, whether or not the focus priority mode is in effect, and whether or not AF correction is in progress. If YES is determined in step S, the focal length (PZENDF) when the driving of the zooming lens group is stopped is stored in S. 120, and the process proceeds to the flowchart shown in FIG. 6 by R to follow the power zoom drive. Make a correction.

On the other hand, if the power zoom drive is not being performed in S. 105 and 108 and it is determined to be NO, the flag mark of the AF correction associated with the power zoom drive of the zooming lens group is set to 0 in S. 121, and S. 122 And the power zoom drive switch is T
Judge whether the ele side is the Wide side. That is, in this embodiment, it is determined which of the Tele side zoom switch SWPZT and the Wide side zoom switch SWPZW is turned on.

If it is Wide, it is S.123, and if it is Tele, it is S.123.
At 124, it is determined whether or not the zooming lens groups are located at the end points on the same side. If they are located, they are returned. If they are not located at the end points, S. 12
Subroutines (see FIG. 8 or FIG. 9) are executed at 5 and 26 to drive to the end points.

Then, after these S. 125, 126, in S. 127, 128, it is determined whether or not the AF is in progress and whether or not the focus priority mode is set, and in S. 129, 130, it is determined whether or not the release is permitted. It is determined whether or not the photographic lens in use is a so-called varifocal lens, which is accompanied by a change in the image forming position during zoom driving. The information as to whether or not the taking lens is a varifocal lens is determined by reading from the unique information stored in the lens ROM 67 built into the taking lens L.

Then, in these S. 127-130, all YES
If it is determined that the focal length (PZSTRTF) at the start of driving the zooming lens group is stored in S. 131,
In S. 132 to 134, the release permission flag mark is set to 0, the focus display is turned off, and the power zoom drive is used.
The AF correction flag mark is set to 1 and the process returns.

On the other hand, if the determination at S. 127 to 130 is NO, the process skips the subsequent steps and returns.

Next, a flow chart connected to R will be described with reference to FIG.

In S. 135, when the AF is in progress in S. 117 to 119, the focus priority mode is set, and the AF correction is in progress, when the driving of the zooming lens group stored in S. 131 is started. A correction value (PSTRT) corresponding to the focal length (PZSTRTF) is read from the lens ROM 67.

This is to calculate the amount of shift of the focusing lens group due to the driving of the zooming lens group below.

Then, in S. 136, similarly, the correction value (PEND) corresponding to the focal length (PZENDF) when the driving of the zooming lens group that was stored in S. 120 is read, and in S. 137 (PSTRT
-PEND) is calculated and used as the focusing correction amount (AFCR).

Focus correction amount (AFCR) for S. 138
Determines whether or not is 0, and if NO, AFC in S. 139
Let the absolute value of R be dP.

In S.140, it is determined whether or not the AFCR is positive, and in the case of NO, in S.141, the focusing lens group is set to N.
A subroutine (Fig. 11) for driving toward the ear end is executed, and if YES, a subroutine (Fig. 12) for driving toward the Far end is executed at S. 142.

Then, in S. 143, it is determined whether or not the driving of the dP is completed, and in the case of NO, in S. 144, the AF pulser 6
It is determined whether the pulse output interval of 8 is 100 msec or more and the focusing lens group reaches the end point. YE
If it is judged as S, the AF end point processing subroutine (Fig. 13) is executed at S. 145 and proceed to S. 147. If it is judged as NO, it returns to S. 143 and circulates S. 143, 144, Wait for the end of dP drive or the detection of the end point.

On the other hand, if YES is determined in S. 143 as the dP drive amount is completed, the AF drive stop subroutine (FIG. 14) is executed in S. 146, and the process proceeds to S. 147.

In response to S. 145 and 146, in S. 147 and 148, it is determined whether or not the focusing lens group exists at the near end or the far end, and the focusing lens group is
S if neither near nor far end.
Proceed to 149, if any, skip the following steps and return.

On the other hand, if AFCR = 0 is determined in S. 138, the process skips S. 139 to 148 and proceeds to S. 149.

In response to these S. 148 and S. 138, the release permission flag mark is set in S. 149, the focus display is lit on the LCD 12 in S. 150, and the process returns.

As is clear from the above description, if the power zoom is driven after focusing on S.8, the focal length of the zooming lens group stored in S.120 and S.131 of the power zoom drive check process by the timer interrupt process The correction value corresponding to is read out from the lens ROM 67, the focusing lens group is driven and corrected in S. 141 and S. 142 based on the calculation result, and if the correction is made, the release permission and combination are performed in S. 149 and 150. The focus is displayed.

Therefore, even in such a case, it is possible to reliably prevent out-of-focus shooting.

The subroutine used in FIGS. 4 to 6 will be described below with reference to FIGS. 7 to 15.

First, the initialization subroutine will be described with reference to FIG.

This initialization subroutine forms part of the main flow chart relating to automatic focusing explained in FIG. 4, and enables timer interruption in SI. 127, as will be described later. Therefore, the power zoom shown in FIG. The drive check process and the release process are performed as part of the timer interrupt process.

When entering the initialization subroutine, first, SI. 101
It is determined whether or not the AF mode switch has been input at, the switch is turned on, and if the AF mode is set,
At SI. 102, a subroutine for driving the focusing lens group to the Far end is executed (see FIG. 12).

In SI. 103, the AF pulse output interval is 100 m.
It is determined whether or not sec or more.

This is 100 msec or more because it is considered that the focusing lens unit is located at the Far end.

If it is 100 msec or more, the AF stop subroutine (see Fig. 15) is executed in SI. 104, and the flag mark that the focusing lens group is at the Far end and that the focusing lens group is not at the Near end are displayed. Flag marks are set up on SI. 105 and 106 and proceed to SI. 109.

On the other hand, when it is determined that the manual mode is set in SI. 101, a flag mark indicating that the focusing lens group does not exist at the Far end in SI. 107 and SI. 108, and Nea
A flag mark indicating that it does not exist at the r end is set, and SI.
Proceed to 109.

In SI. 109, the pulse number Pinf corresponding to the distance from the Far end of the focusing lens unit is set to 0, and SI. 11
In 0, SI. 111, a flag mark indicating that the zooming lens unit is not located at the Wide end and a flag mark indicating that the zooming lens unit is not located at the Tele end are set.

Then, in SI. 112 and SI. 113, a flag mark indicating that the focusing lens group by the zoom return drive in the macro region does not exist at the Far end and a flag mark indicating that the focusing lens unit does not exist at the Nert end are set.

Furthermore, in SI. 114 to SI. 116, a flag mark indicating that release is not permitted, a flag mark indicating that manual focus is not in progress, and a flag mark indicating that auto focus is not in progress are set in order.

Then, in SI. 117, it is determined whether the macro switch is on or off.

If the macro switch is turned on, SI. 118 sets a flag mark to that effect, and if the macro switch is off, SI. 119 sets a flag mark to that effect.

After these SI. 118 or SI. 119, SI. 120 ~ S
In I.122, a flag mark indicating that the focusing lens unit is not being driven, a flag mark indicating that the zooming lens unit is not being driven, and a flag mark indicating that the zooming lens is not being AF-driven in the macro area are set in order.

Further, in SI. 123 to SI. 125, the flag mark indicating that power zoom drive is possible, the flag mark for starting the constant image magnification control, and the flag mark indicating that the constant image magnification control is in progress are set to 0, respectively. , Start a 5msec timer in SI. 126, enable timer interrupt in SI. 127, and return.

Next, a subroutine for driving the zooming lens group in the Wide direction will be described with reference to FIG.

When this subroutine is entered, driving of the zooming lens group in the Wide direction is started in S. 201, and since the zooming lens group is being driven in the Wide direction in S. 202, the flag mark for driving in the Tele direction is set to 0. , Also, in S. 203, a flag mark indicating that the zooming lens group is being driven is added.

Then, in S. 204 and S. 205, a flag mark indicating that the zooming lens unit is not located at the Tele end and a flag mark indicating that the zooming lens unit is not located at the Wide end are added.

Also, in S. 206 and S. 207, a flag mark indicating that the focusing lens unit is not located at the Near end in the macro region and a flag mark indicating that the focusing lens unit is not located at the Far end in the macro region are added, and the return is performed. It

Next, referring to FIG. 9, a subroutine for driving the zooming lens group in the Tele direction will be described.

When this subroutine is entered, first, in S. 301, driving the zooming lens group in the Tele direction is started, and in S. 302, the flag mark indicating that the zooming lens group is driving in the Tele direction is set to 1, and in S. 303, zooming is performed. Add a flag mark that the lens group is driving.

Then, in S. 304 and S. 305, a flag mark indicating that the zooming lens unit is not located at the Tele end and a flag mark indicating that the zooming lens unit is not located at the Wide end are attached.

Further, in S. 306 and S. 306, a flag mark indicating that the zooming lens group is not located at the Near end in the macro region and a flag mark indicating that the zooming lens unit is not located at the Far end in the macro region are added and the process is returned.

Next, the contents of the subroutine for stopping the driving of the zooming lens group will be described with reference to FIG.

S. 40 in the subroutine for stopping the zooming operation
1 and S. 402, it is determined whether the zooming lens group is being driven in any of the zooming area and the macro area. If the zooming lens group is not being driven in any area, the process is returned as it is.

If the zooming lens group is being driven in any area, the driving of the zooming lens group is stopped in S. 403, and the zooming lens group is stopped in any area in S. 404 and S. 405. Put a flag mark to that effect and return.

Next, referring to FIG. 11, the contents of the driving subroutine for the focusing lens group in the direction toward the Near end will be described.

When the subroutine for driving the focusing lens group toward the Near end is entered, the focusing lens group is set to Nea in S. 501.
Since the driving is started toward the r end and the focusing lens group is driving in the Near direction in S. 502, the flag mark for driving in the Far direction is set to 0, and the focusing lens group is driving in S. 503. Put a flag mark to the effect.

Then, in S. 504 and S. 505, a flag mark indicating that the focusing lens group does not exist at the Near end is attached, and a flag mark indicating that the focusing lens group does not exist at the Far end is attached and the process is returned.

Next, referring to FIG. 12, the contents of the driving subroutine for driving the focusing lens unit in the Far end direction will be described.

When the subroutine for driving the focusing lens group toward the far end is entered, the focusing lens group is moved to Far with S. 601.
The drive starts in the end direction, and the S.602 focusing lens group is driving in the Far direction. Therefore, the flag mark for driving in the Far direction is set to 1 and the focusing lens group is driving in S.603. Put a flag mark.

Then, in S. 604, a flag mark indicating that the focusing lens group does not exist at the Near end is attached, and in S. 605, a flag mark indicating that the focusing lens group does not exist at the Far end is attached and the process is returned.

Next, the contents of the AF end point processing subroutine shown in FIG. 13 will be described.

When entering the AF end point processing subroutine, the AF stop subroutine (see Fig. 15) is executed in S. 701, and S. 702
Calculate the number of pulses dPX driven until the focusing lens group is stopped at.

Then, in S. 703, it is determined whether or not the direction in which the focusing lens unit was driven is the Far end direction, and NO
In the case of S. 704, dPX calculated in S. 702 is added to the number of pulses Pinf corresponding to the amount of extension from the Far end of the focusing lens group to obtain Pinf, and in S. 705, Pinf and Pnear (Fn
Pint is the absolute value of the difference in the number of pulses from the ar end to the Near end)
Define it as (the number of pulses to the Near end), and proceed to S. 706.

In S. 706, it is determined whether or not Pint is smaller than e (the number of allowable error pulses, for example, e = 10),
In the case of NO, the subroutine (FIG. 11) for driving the focusing lens unit to the Near end side is executed in S. 707, and S. 70
At 8, it is determined whether the AF pulse output interval is 100 msec or more.

If the time is 100 msec or longer, execute the AF stop subroutine (Fig. 15) for the focusing lens group in S.709 to execute S.709.
Proceed to 710, and if less than that, repeat S. 708 and wait for the detection of the end point.

On the other hand, if YES in S. 706, S. 70
Fly from 7 to 709 and proceed to S. 710. This is because it is within a predetermined error range.

Then, in S. 710, a flag mark indicating that the focusing lens unit exists at the Near end is added, and the S. 71
In 1 rewrite Pinf with Pnear to eliminate error accumulation and return.

If YES is determined in S. 703, in S. 712, the pulse number Pinf corresponding to the amount of extension from the Far end of the focusing lens group is subtracted from dPX calculated in S. 702 to Pinf, and S. The absolute value of Pinf is defined as Pint (the number of pulses up to the Near end) in 713, and S.714 is followed.

In S. 714, it is determined whether Pint is smaller than e (permissible error pulse, for example, e = 10) as in S. 706. If NO, the focusing lens group is set in S. 715. Execute the subroutine (Fig. 12) to drive to the Far end side, and proceed to S.716.

In S.716, it is determined whether or not the AF pulse output interval is 100 msec or more. If it is 100 msec or more, in S.717, the AF stop subroutine of the focusing lens group (15th
Figure) and if less, repeat S. 716,
Wait for the end point to be detected and proceed to S.717.

On the other hand, if YES in S. 714, S. 71
Fly 5 to 717 and proceed to S. 718. This is because it is within a predetermined error range.

In S. 718, a flag mark indicating that the focusing lens group exists at the far end is added, and in S. 719, Pinf =
The origin is corrected to 0 and the process returns.

Next, the contents of the AF drive stop subroutine will be described with reference to FIG.

When the AF drive stop subroutine is entered, the AF stop subroutine (see Fig. 15) is executed in S. 801 and S. 802
The number of pulses dPX driven until the focusing lens group is stopped is calculated in step S. 803.

In S. 803, it is determined whether or not the direction in which the focusing lens group was driven is the Far end side direction, and in the case of NO, in S. 804, it corresponds to the extension amount from the Far end of the focusing lens group. Calculated by S. 802 to pulse Pinf dPX
And add as Pinf and proceed to S.805.

In S. 805, it is determined whether Pinf is smaller than Pnear (the number of pulses from the Far end to the Near end). If YES, the process is returned. If NO, the focusing lens group is moved toward the Near end in S. 806. Execute the driving subroutine (Fig. 11) and proceed to S.807.

In S. 807, whether the AF pulse output interval is 100 msec or more is used to determine whether the end point has been reached, and 100 m
If it is longer than sec, the AF stop subroutine (Fig. 15) is executed in S. 808 and proceed to S. 809. If it is shorter than that, S. 807 is repeated.

Then, in S. 809, if the focusing lens group is N
With a flag mark indicating that it exists at the end of the ear, in S. 810
Rewrite Pinf with Pnear and return.

On the other hand, if YES in S. 803, S.
At 811, dPX calculated at S.802 is subtracted from the pulse number Pinf corresponding to the amount of extension from the Far end of the focusing lens group to obtain Pinf, and at S.812, it is determined whether Pinf is positive.

If YES, the process returns, and if NO, the subroutine for driving the focusing lens unit to the Far end side in S. 803 (first
2) and proceed to S.814.

In S. 814, similarly to S. 807, it is determined whether the AF pulse output interval is 100 msec or more.

If it is 100 msec or more, proceed to S.815, execute the AF stop subroutine (Fig. 15) and proceed to S.816, and if it is less than that, repeat S.814.

In S.816, a flag mark indicating that the focusing lens group exists at the far end is added, Pinf is set to 0 in S.817, and the process returns.

Next, referring to FIG. 15, the AF stop subroutine will be described.

When the AF stop subroutine is entered, it is determined in S.901 if the focusing lens group is in AF drive and YE
In case of S, proceed to S. 902, and in case of NO, return as it is.

In S. 902, the driving of the focusing lens group is stopped, and in S. 903, a flag mark indicating that the driving of the focusing lens group is stopped is added, and the process returns.

(Effects of the Invention) As described above, according to the present invention, since the focus deviation caused by zooming is corrected according to the focal length data before and after zooming, before zooming,
Alternatively, it becomes possible to perform more accurate focus compensation than correcting the focus according to one of the subsequent focal length data.

[Brief description of drawings]

1 is a block diagram showing the entire system, FIG. 2 is a circuit diagram inside a camera body, FIG. 3 is a circuit diagram inside a photographing lens, and FIG. Main flowchart of automatic focusing in this system, FIGS. 5 and 6 are flowcharts of power zoom drive check processing, FIG. 7 is a subroutine of initialization, and FIG. 8 is a subroutine for driving the zooming lens group in the Wide end direction. , Fig. 9 shows Tele of zooming lens group
Driving subroutine in the end direction, FIG. 10 is a subroutine for stopping the driving of the zooming lens group, FIG. 11 is a subroutine for driving the focusing lens group in the Near end direction, and FIG. 12 is driving in the Far end direction of the focusing lens group. Subroutine, Fig. 13 shows AF end point processing subroutine, Fig. 14 shows
AF driving stop subroutine, FIG. 15 is an AF stop subroutine. L: taking lens, SW S: focusing operation command output means (photometric switch), 10, 11, 66; CPU, 60; drive means, 67; storage means (lens ROM).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Kawasaki Inventor Masahiro Kawasaki 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd. (56) Reference JP-A-62-231207 (JP, A) JP 62-296110 (JP, A) JP 62-62313 (JP, A) JP 1-304411 (JP, A) JP 62-284317 (JP, A) JP 61-133912 (JP , A)

Claims (1)

[Claims] 1. A photographing lens having a focusing lens group and a zooming lens group, a storage means for storing unique information of the photographing lens, a driving amount of the focusing lens group is calculated from a defocus amount, and the calculation result is obtained. Based on the driving means for driving the focusing lens group, and the output means of the focusing operation command for maintaining the state of the focusing lens group as it is after focusing, the storage means is provided with the taking lens, This storage means stores data on the relationship between the focal length of the taking lens and the focus shift, and when the zooming lens group is moved while the output means for the focusing operation command is on, the storage means is stored. Read the correction value based on the focal length before zooming and the correction value based on the focal length after zooming. Automatic focusing device of a camera having a zoom lens, characterized by driving the driving means based on the difference value.