JPH0293441A - Automatic focusing device for camera with zoom lens - Google Patents

Abstract

PURPOSE:To enhance the degree of freedom for using a zoom lens at the time of determining the composition, etc. in a finder by preventing surely a focal shift by executing automatic focusing again, even if zooming is executed in a focus lock state after focusing. CONSTITUTION:When a first auto focus switch SWAF1 for setting the focusing to an auto mode by driving an AF motor is turned ON, and a focusing priority mode is selected by a second auto focus switch SWAF2, and also, a power zoom mode is selected and focused by a zoom changeover switch SWPZ1, when a zooming lens group is driven by a zoom switch SWPZT or SWPZW, a power zoom driving check is executed, and thereafter, it is returned to an AF processing again and automatic focusing is executed, and thereafter, a release is executed by a timer interruption processing. Even when zooming is executed by a power zoom, it is brought to focusing by a second AF processing, therefore, photographing of a focal shift is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic focusing device for a camera having a power zoom lens.

(Conventional technology) Recently, 9! of electronics technology! In recent years, various automatic cameras have been realized which are equipped with an automatic focusing device and a power zoom lens in which a zooming lens group is driven by a driving means such as a motor.

With this type of automatic focusing device, for convenience of determining the composition in the viewfinder, after focusing with the automatic focusing device, turn on the metering switch, and then the camera will automatically shoot until the release process. The operation of the focusing device can be temporarily stopped.

Some devices have a so-called focus lock function.

By the way, if you install a zoom lens on 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 lock state.

On the other hand, the zooming lens group should always form the subject image on the film surface within the zooming range, but due to manufacturing reasons, the image forming position cannot be adjusted by zooming. There are some things that cause misalignment.

(Problem to be solved by the invention) For this reason, if you move the zoom lens after focusing with the automatic focusing device, it will not necessarily remain in focus, and if you continue to take photos, the focus will shift. There is a risk that a photo shoot will be taken.

The present invention was made based on this background, and an object of the present invention is to prevent out-of-focus photography in this type of camera even when zooming is performed after the camera has been heated to a certain degree. It is something.

(Means for Solving Problem 8) Therefore, the present invention provides a photographic lens having a focusing lens group and a zooming lens group, and calculates the driving amount of the focusing lens group based on the defocus amount and performs an adjustment based on the calculation result. It has a driving device that drives the focusing lens group, and a focusing operation command output means that maintains the state of the focusing lens group in the same state after focusing, and keeps the focusing operation command output means turned on. When the zooming lens group is moved, the driving amount of the focusing lens group is calculated again from the defocus amount, and the driving device is driven based on the calculation result.

(Function) Therefore, even if you perform zooming in the focus lock state after focusing, automatic focusing will be performed again to bring the camera into focus, which will reliably prevent out-of-focus shooting and allow you to use a zoom lens. The degree of freedom in using the zoom lens increases when determining the composition etc. in the viewfinder.

(Example) This invention will be described below with reference to an example of an automatic eye reflex camera shown in the drawings, in which a lens unit is integrally installed in a camera body. It goes without saying that the same method can be applied to so-called compact cameras and still video cameras.

The camera body CB of this automatic eye-reflex camera has a known structure on which various photographic lenses as shown in the figure can be attached interchangeably.
A power zoom type photographic lens L is attached to the camera.

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

The camera body CB is equipped with two CPUs: a main CPU 10 that performs various types of information processing for photographing, and a display CPU II that mainly performs information input via switches, exchanges and displays information on the photographic lens L, etc.

The LCD panel 12 that displays various information centering on these CPUs, the DX printed on the cartridge
A DX code input circuit 13 inputs the ISO sensitivity of the film used from the code, a light receiving element 14 measures the brightness of the subject from the light flux incident through the photographing lens L, and A/D converts the output of this light receiving element. A/D circuit 15,
an exposure control circuit 16 that controls the shutter based on various input shooting conditions; and an AF control circuit 16 that receives a subject image formed by a flux of light incident through the photographic lens L;
A CCD processing circuit 18 is provided for detecting the focusing state of the photographing lens L from the output of the CD 17 and the AF CCD 17.

Further, an autofocus (AF) motor 19 for performing lens focusing includes an AF motor control circuit 20 that calculates the output of the CCD processing circuit 18 and drives the AF motor 19, and detects the drive amount of the AF motor 19 as a pulse. When a conventional type photographing lens L having no AF motor inside the lens is mounted together with the AF pulser 21, driving force is transmitted to the photographing lens L side through a coupler 19a provided at the mount opening.

However, this is not used in the situation shown in FIG.

The battery 22 not only supplies power to each active element in the camera body CB, but also powers a motor in the photographic lens L, which will be described later.
While power is also supplied to the PU, the photographing lens L has an AF motor 60 (corresponding to the driving means in the present invention), a power zoom (PZ) motor 61, and an automatic aperture control (AE) internally. It has three built-in motors including a motor 62, and has a structure in which autofocus, power zoom, and aperture control are all performed by driving force within the lens.

Note that the photographing lens L has a cam mechanism similar to the conventional one that performs focusing and zooming by moving each lens group relative to each other in the optical axis direction by rotating a cam ring, and the AF motor 60 and PZ motor 61 described above are Each rotates a cam ring.

Each motor is connected to the lens CPU 6 via an AF motor drive section 63, a PZ motor drive section 64, and an AE motor drive section 65.
6.

As information input means to the lens CPU 66, a lens ROM serving as a storage means for storing lens-specific information is used.
87. AF that detects the drive amount of each motor by converting it into pulses
Pulsar 68, PZ Pulsar 69, AE Pulsar 70,
A zoom code plate 7 detects the rotational positions of the zooming cam ring and the focusing cam ring.
1 and a distance code plate 72.

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

In addition to being connected to the control target and input means described above, the lens CPU 66 is also capable of communicating with the camera body CB via an electrical contact group TC, which will be described later. In response to the defocus amount, the driving amount is calculated while referring to the data in the lens ROM 67, and the AF motor 60 is driven while the driving amount is detected by the AF pulser 68. It has a function of rotationally driving the AE motor 62 while detecting the drive amount by the AE pulser 70 based on the aperture value determined on the camera body CB side.

The lens mount port of the camera body CB has an electrical contact group TI consisting of 10 electrical contacts insulated from the base.
(See Figure 2).

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

When the photographic lens L is mounted on the camera body CB, these electrical contact groups TI.

Contacts with the same name T2 form the electrical contact group TC described above.

This system will be explained below based on a more detailed circuit diagram.

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

vDD1gJ child of display CPU11, battery 2
2 is supplied after being transformed by the regulator R and backed up by the supercapacitor 24.
Operates at constant voltage.

In addition, the P1 terminal of the display CPU II is connected to the main CPU 10.
0N10FF 6DC/DC:7 pumper 25
The P2 terminal is connected to the photometry switch SWS, which is turned on by pressing the shutter button once, and the P3 terminal is the release switch SW, which is turned on by pressing the shutter button twice.
The R and P4 terminals are connected to a lock switch 3WL that is turned on when the camera is placed in a shooting state, and data of each switch is input.

Note that the photometry switch SWS corresponds to the focus lock switch in the present invention, and in automatic focusing processing in power zoom and focus priority mode, by turning on this photometry switch SWS, the focus is locked until the release is released. The focus is locked by maintaining the state of each lens group when in focus.

The D C/DC converter 25 is a lock switch SWL
When the photometering switch SWS is turned on while the main CPU is turned on, power is supplied to the VDD terminal of the main CPU to activate it.

Furthermore, the P5 terminal is a mode switch SWM that allows selection of shooting modes such as program shooting, auto shooting, manual shooting, etc. at 8 o'clock, and the P6 terminal is a drive switch S that allows selection of shooting modes such as single shooting, quick shooting, etc. at 08 o'clock. W
DR, P? The terminal is connected to the exposure compensation switch 5WXV which enables the exposure set at 08:00 to be compensated, and the switches connected to these P5 to P7 are set to ONL.
, the respective settings can be changed by operating the up-count switch 5WLIP connected to the P8 terminal or the down-count switch 5WDN connected to the P9 terminal.

The P SEG terminal group is for driving the LCD panel 12, and displays stored information when the lock switch SWL is turned on.

The PA contact group of the main CPU II is the A/D circuit 1 for photometry.
5, and the PB contact group is connected to exposed circuit 16, pc
The contact group is the COD processing circuit 18, the PD contact group is the AF motor control circuit 20, the PE contact group is the AF pulser 21. The PF contact group is connected to the DX input circuit 13.

The A/D circuit 15 is connected to the light receiving cable 14 for photometry, the COD processing circuit 18 is connected to the CCD 17 for AF, and the AF motor control circuit 20 is connected to the A/D circuit 14 in the camera body CB.
As described above, it is connected to the F motor 19.

The P20 terminal of the main CPU 10 is connected to the first autofocus switch 5WAPI, which switches focusing between an auto mode driven by the AF motor and a manual mode driven manually by the user, and the P21 terminal is connected to the shutter release switch 5WAPI. It is connected to a second autofocus switch 5WAP2 that switches the mode between focus priority and release priority.

FIG. 3 shows the circuit of the photographing lens L.

The lens side V BATT contact is connected to each motor drive unit 83, 64.65 in the lens, and switching of these drive units causes each motor 60. 61. 62 directly.

In addition, each motor drive unit 83, 64, 65 is a lens CPU.
66 P)1. It is configured to be connected to and controlled by the PI and PJ terminal groups, and the pulser 88.
69.70 is connected to terminals P20 to P22 and is configured to input the detected drive amount of each motor to the lens CPU 66.

The Vdd contact connects the power supplied from the display CPU 11 on the camera body CB side to the Vdd terminal of the lens CPU 86.
It is supplied to a reset circuit consisting of a resistor R, a diode D, and a capacitor C.

The reset circuit has a certain time constant using a resistor and a capacitor, and changes the m terminal of the lens CPU 8B from active (L) to non-active (H) after a certain period of time has passed since Vdd has been applied and the power supply voltage has stabilized. It has a function to switch and start the program of the lens CPU'6.

The P23 to P27 terminals of the lens CPU 68 are provided on the lens side, and are used as a third autofocus switch 5WAP3 for switching between automatic and manual autofocus, and a zoom changeover switch for selecting whether zooming is performed automatically by a motor or manually. S W PZI,
An image magnification constant switch 5WPZ2 automatically performs zooming as the object moves relative to the object so as to maintain the image magnification of the object, and a PZ motor 69 to move the photographic lens L in a direction where the focal length of the photographic lens L becomes longer. A Te1e-side zoom switch 5WPZT to be driven and a Wide-side zoom switch swpzw to drive a PZ motor to move the lens in the direction of shortening the focal length are connected, respectively.

The lens CPU 66 has an INT terminal to which an electrical signal that interrupts program execution of the CPU is input;
The SCK terminal to which the serial clock from the display CPU 11 on the camera body CB side is input, the Sl/Som terminal for serial data transfer, and the m terminal for synchronizing the serial communication of the lens CPU 66 with peripheral devices. We are prepared.

The INT terminal is connected to the lens CPU66 at L-1-H after the ■ side.
CPυ11 for display on the camera body side B side to enable interrupts, and to prevent serial communication from being executed with the m terminal set to H.
is placed on standby, and serial communication is enabled with L.

Furthermore, the PK terminal group of lens CP066 is connected to lens RO.
The zoom code plate 71 is similar to the PL and PM terminal group of M87.
and a distance M code plate 72 are connected, and the focal length information and distance information corresponding to the actual lens condition are input.

The lens ROM 67 stores unique information of the photographing lens L, such as fixed information and variable information such as the maximum aperture F number, the minimum aperture F number, and the amount of change in the F number due to zooming.

The information stored in the lens ROM 67 is transferred to the camera body CPU via the electrical contact group TC under the control of the lens CPU 66 or directly in response to a request from the camera body side CPU. In a camera system configured in this way and having the functions described above, the first autofocus switch 5WAPI is turned on, and the second autofocus switch 5WAP2 selects the focus priority mode. , Furthermore, the zoom changeover switch 5WPZI
When the power zoom mode is selected and the camera is focused, if the zooming lens group is driven by the Te1e side zoom switch SW PZT or the Wide side zoom switch swpzw, automatic focusing is performed again as described below. Ru.

The process will be explained below using flowcharts shown in FIGS. 4 to 14.

Below, first, a flowchart regarding the power zoom drive check will be explained with reference to FIG.

The following program is the main automatic focusing program (see Figure 5) that starts when the lock switch SWL is turned on, the photometry switch SWS is turned on, and power is supplied from the DC/DC converter 25. This is performed in the same way as the release processing in the timer interrupt processing for A release process is performed by the process.

In the power zoom drive check process, it is determined whether or not the power zoom route is selected at 8°1, and if it is determined to be YES because it is the power zoom mode, 3. 2 and 3. In step 3, it is determined whether constant image magnification control is being performed and whether power zoom driving is being performed for AF in a macro area.

These 3. 2 and 3. If it is judged as YES in step 3, the process returns because it is not subject to processing, and if it is judged as no in step 3. 4 to Wide side zoom switch s
Determine whether wpzw is on or off.

If the Wide side zoom switch is determined to be on, 3
, 5, it is determined whether or not the zooming lens group is being driven. If YES, it is determined in S, 6 whether or not the driving direction of the zooming lens group is the Te1e direction.

On the other hand, 3. If it is determined that the Wide side zoom switch is off in step 4, step 3. 7 to 9, regarding the Te1e side zoom switch 5WPZT in 3. Judgments similar to 4 to 6 are made.

And these 3. 4-6 and 3. In steps 7 to 9, if any 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, the output interval of the zoom pulse of the PZ pulser 69 is changed in step 8.10. is 100
It is determined whether it is equal to or higher than m5ec.

If 100 o+sec is not grooved, the zooming lens group is being driven, so the process returns, and if it is more than that, it is considered that the zooming lens group has reached the end point, so in 3.11 the zoom stop subroutine ( 9th
(see figure), and in 8.12 the zooming lens group is set to T.
e1e Determine whether or not it was driven in the end direction, and answer YES
In the case of 8.13, a 7 lag mark indicating that the zooming lens group exists at the Te1e end is added, and in the case of NO, a flag mark indicating that the zooming lens group exists at the Wide end is added in 8.14.3. Proceed to 17.

On the other hand, above 3. 1. If it is determined that the mode is not power zoom mode and No, the above 3. 4 and S,
7 with both Te1e and Wide power zoom switches turned off, and 8.15
At 8.15, it is determined whether or not the power zoom is in operation. If NO, the process returns; if YES, the zoom stop subroutine is executed at 8.16 (Figure 9).
The tangent after executing this moves to 8°17.

These 3. 13, 14. In response to 16, 8°17~
In step 19, it is determined in order whether or not AF is in progress, whether or not the focus priority mode is on, and whether or not it is in the center of AFF, and if it is determined YES in all of these steps, in step 3.20. The focal length (PZENDF) when the drive of the zooming lens group is stopped is memorized, the timer interrupt is enabled at 8.21, the rough flowchart for AF shown in Fig. 5 is proceeded through A, and the automatic focusing is performed again as described later. and perform corrections associated with driving the power zoom.

On the other hand, above 8. If power zooming is not in progress in steps 5 and 8 and the determination is NO, 3. At 22, the flag mark for AF correction accompanying the power zoom drive of the zooming lens group is set to 0, and at 8.23, it is determined whether the power zoom drive switch is on the Te1e side or the Wide side. That is, in this embodiment, the Te1e side zoom switch 5
It is determined which of the WPZT and the wide side zoom switch swpzw is turned on.

If it is on the Wide side, it is determined at 8.24, and if it is on the Te1e side, it is determined at 8.25 whether or not the zooming lens group is located at the end point on the same side. If it does not exist at the end point, the respective subroutines (see FIG. 7 or 8) are executed at S and 26 and 27 to drive to the end point.

And these 3.26. After 27, 3. 28.
At step 29, it is determined whether AF is in progress and whether or not the focus priority mode is set, and at step S, 30° and step 31, it is determined whether release permission is given and the attached photographic lens is determined to focus on zoom drive. It is determined whether the lens is a so-called varifocal lens that involves a change in position.

The information as to whether this photographic lens is a varifocal lens is stored in the lens ROM built into the photographic lens L.
This is determined by reading out the unique information stored in 87.

However, in these 8.28 to 31, all Y
If it is determined to be ES, the focal pressure M (PZSTRTF) at the start of driving the zooming lens group is memorized at 8.32, and the release permission flag mark is set to 0 in sequence at 8.33 to 8.35, and the focus display is displayed. The light goes out, the flag mark for AF correction by power zoom drive is set to 1, and the process returns.

On the other hand, if there is a determination of No in 8.28-31 above,
Skip the subsequent steps and return.

Next, a flowchart connected to step A will be explained with reference to FIG. 5. Since this flowchart is the main flowchart regarding automatic focusing, the explanation will be given from the start.

That is, this program executes the lock switch SW.
With L turned on, the photometry switch SWS is turned on, and power is supplied from the DC/DC converter 25 to start.

In this way, when you start, first 8. At 8.36, the initialization subroutine is executed, and at 8.37
The contents of the initialization subroutine will be explained later with reference to FIG.

At step 8.37, it is determined whether the AF mode switch (third autofocus switch 5WAP3) is input and the AF mode is set.

If the camera is not in AF mode, it is not subject to the processing according to this flowchart, and this is to exclude such cases.

Therefore, in AF mode, 3. 38, but if the mode is a manual mode other than the AF mode, manual mode processing is performed and automatic focusing is not performed (M in the fourth diagram).

At step 8.38, it is determined whether manual focus is in progress.

If YES, it means that the AF mode has been switched to manual focus, so as in 8.37 above, it is not subject to the processing in this flowchart, and N
Return the G processing mode to 8°37 with light and enter the manual mode (K in the fourth diagram).

If NO, proceed to 8.39 and switch the photometry switch SWS.
Determine whether or not is turned on, and if YES, S, 4
When the value is 0, a flag mark is placed indicating that the AF mode is in progress, and the AF operation starts.

If 8.39 is determined as No, the user's intention to take a picture is not confirmed, so the process returns to 8.37 above.
The process cycles through steps 37 to 39 and waits for the photometry switch SWS to be turned on.

When AF operation starts at 8.40, AF C starts at 8.41.
Defocus amount dx detected by a detection device such as 0D17
is calculated, and in step S42 it is determined whether the contrast of the signal detected by the CCD 17 is low.

If YES, it is difficult to focus using the CCD 17, so the process returns to 8.37, cycles through 8.37 to 42, and waits for contrast to be restored or manual mode to be selected.

If NO, it is determined in step 5.43 whether or not it is in focus.

If it is not in focus in the current state, it is judged as No, and the process proceeds to 8.44-46, and the release switch S is
A flag mark is placed to prohibit the operation of WR, the focus display is turned off, and the driving fidP of the focusing lens group is calculated from the defocus fidx.

On the other hand, if it is determined that the focus remains as it is at 8.43 above, the process proceeds to 8.47-51, and 8.4
7, it is determined whether image magnification constant control is being performed, and N
In the case of O, the focus display lights up and the release switch SWR is pressed.
A flag mark is attached to permit the operation of 8.50, and the process proceeds to 8.50. Therefore, release processing by timer interrupt processing becomes possible after 8.49.

On the other hand, if YES at 8.47, the focus display is turned off at 8.51 and the image magnification constant control mode is entered (B).

In 8.50, it is determined whether or not the focus priority mode is set, and if YES, the focus is locked by cycling, and if NO, the process returns to 8.37 (A).

On the other hand, as described above, if the determination is No at 8.43 and the driving JtdP of the focusing lens group is calculated, then at 8.52, the driving direction of the focusing lens group is determined from the signal of the detection means, Drive direction is Near
In the case of the side, check whether the focusing lens group exists at the Near end in 8.53, and in the case of the Far side, check in 8.54 whether the focusing lens group exists at the Far end.
Determine whether it exists at the edge.

If YES is determined in 8.53.54, AF processing is started in the macro area.

If it is determined No in 3.53.54, the subroutine (8.55 or 8.56) moves the focusing lens group to the end point on the drive direction side.
(See Figures 10 and 11) and both are 8.57.
Proceed to.

In 8.57, the driving f of the focusing lens group
It is determined whether or not the driving of the idP is completed, and if No, the pulse output interval of the AF pulser 68 is set to 10 at 8.58.
Determine whether it is greater than or equal to 0 rthsec and send 100 m5e
If it is greater than or equal to c, the AF end point processing subroutine (see FIG. 12) is executed in step S59, and the process returns to 3.37.

If it is less than 100 m5ec, return to 8.57 and wait until the drive jldP ends or the output interval of the AF pulser 68 reaches 100 m5ec in step 3. 57. 5
Cycle 8 and wait.

On the other hand, the driving amount dP of the focusing lens group is 8.57.
When the driving is completed and it is judged as YES, the process proceeds to 8.60, executes a subroutine to stop the AF driving (described later in FIG. 13), returns to 8.37, and returns to 8.37.
~43 and 3. If it is in focus at 47-51, release processing is possible, and if it is not in focus, it is 8.37-46 and 3. Cycle through 52-62.

In this way, from the AF process as shown in FIG. 5, the power zoom drive check process shown in FIG. 4 is performed by the timer interrupt process, and after this power zoom drive check process, the AF process is performed again. After focusing by this AF processing, release processing is performed by timer interrupt processing, so even if the zooming lens group is driven by power zoom after focusing by the previous AF processing, the second AF The camera can be brought into focus through processing, preventing out-of-focus shots.

The subroutines used in FIGS. 4 and 5 will be explained below with reference to FIGS. 6 to 14.

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

This initialization subroutine forms part of the main flowchart related to autofocus explained in FIG. Drive check processing, release processing, etc. are performed as part of the timer interrupt processing.

When entering the initialization subroutine, first 8.10
1, it is determined whether the AF mode switch is input, and if the switch is turned on and the AF mode is in effect, a subroutine for driving the focusing lens group to the Far end is executed at 8.102 (11th step). (see figure).

Then, in 3.103, it is determined whether the output interval of the AF pulse is 100 m5ec or more.

The reason why this is 100 tnsec or more is because the focusing lens group is considered to be located at the Far end.

If it is 100 a+sec or more, the AF stop subroutine (see Fig. 14) is executed in 9.104, and the focusing lens group is aligned with the flag mark present at the Far end and the focusing lens group is near the near Qti.
The flag mark indicating that it does not exist in l is 3.105.106
3.109.

On the other hand, if manual mode is determined in 3.101, a flag mark indicating that the focusing lens group does not exist at the Far end and a flag mark indicating that the focusing lens group does not exist at the Near end are set in 3.107 and 8.108. So, proceed to 8.109.

In 3.109, Fa of the focusing lens group
Let the number of pulses P inf corresponding to the distance from the r end be 0, S, 110. In S, 111, a flag mark indicating that the zooming lens group is not located at the Wide end and a flag mark indicating that the zooming lens group is not located at the Te1e end are set.

Then, in steps 3.112 and 3.113, a flag mark indicating that the focusing lens group driven by the zoom ring in the macro area does not exist at the Far end and a flag mark indicating that the focusing lens group does not exist at the Near end are set.

Further, at S, 114 to S, '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 autofocus is not in progress are set in order.

After that, at 3.117, the macro switch is turned on/off.
Off is determined.

Then, if the macro switch is turned on, 3. A flag mark to that effect is set at 118, or if it is off, a flag mark to that effect is set at 3.119.

These 3.118 or 8.119 (group S, 12
0 to 3. At 122, set a flag mark to indicate that the focusing lens group is not being driven, a flag mark to indicate that the zooming lens group is not being driven, and a flag mark to indicate that the zooming lens is not being driven by AF with macro tilting. .

In addition, in S, 123 to S, 125, the flag mark to enable power zoom driving, the flag mark to start constant image magnification control, and the flag mark to indicate that constant image magnification control is in progress are set to 0, respectively. , 3.1
At 26, start a timer of 5 m5ec, and at 3
．． At step 127, timer interrupt is enabled and the process returns.

Next, with reference to FIG. 7, a subroutine for driving the zooming lens group in the Wide direction will be described.

When this subroutine is entered, the zooming lens group starts to be driven in the wide direction at 3.201, and at 3.20
2, the zooming lens group is being driven in the Wide direction, so the flag mark for driving in the Te1e direction is set to 0.
At 8.203, a flag mark indicating that the zooming group is being driven is added.

Then, at 3.204 and 3.205, a flag mark indicating that the zooming lens group is not located at the Te1e end and a flag mark indicating that the zooming lens group is not located at the Wide end are added.

In addition, in 3.206 and 3.207, a flag mark indicating that the zooming lens group is not located at the Near end in the macro area and a flag mark indicating that the zooming lens group is not located at the Far end in the macro area are added and returned. Ru.

Next, a subroutine for driving the zooming lens group in the Te1e direction will be explained with reference to FIG.

When entering this subroutine, first, at 3.301, the zooming lens group starts to be driven in the Te1e direction, and at 3.30
At 2.2, a flag mark indicating that the zooming lens group is being driven in the Te1e direction is set to 1, and at 3.303, a flag mark indicating that the zooming lens group is being driven is attached.

Then, at 3.304 and 3.305, a flag mark indicating that the zooming lens group is not located at the Te1e end and a flag mark indicating that the zooming lens group is not located at the Wide end are added.

In addition, in 3, 306 and 3.308, there is a flag mark indicating that the zooming lens group is not located at the Near end in the macro area, and a flag mark indicating that the zooming lens group is not located at the Near end in the macro area.
It is returned with a flag mark indicating that it is not located at the r end.

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

3.4 in the subroutine to stop zooming operation
At 01 and 3.402, it is determined whether the zooming lens group is being driven in either the zooming area or the macro area, and if the zooming lens group is not being driven in either area, the process returns directly.

If the zooming lens group is being driven in any area, the driving of the zooming lens group is stopped in 3.403, and the zooming lens group is stopped in any area in 3.404 and 3.405. Returns with a flag mark indicating a certain fact.

Next, according to FIG. 10, Nea of the focusing lens group
The contents of the drive subroutine in the r-end direction will be explained.

When the subroutine for driving the focusing lens group toward the near end is entered, the driving of the focusing lens group toward the near end is started at 3.501, and at 3.502, since the focusing lens group is being driven toward the near end, the focusing lens group is driven toward the near end. Set the flag mark for drive in the direction to O, and set 3.5
At step 03, a flag mark is placed to indicate that the focusing lens group is being driven.

Then, at 8.504 and 3.505, a flag mark indicating that the focusing lens group does not exist at the Near end, a flag mark indicating that the focusing lens group does not exist at the Far end, and the process returns.

Next, according to FIG. 11, the Far of the focusing lens group
The contents of the end direction drive subroutine will be explained.

When the subroutine for driving the focusing lens group toward the Far end is entered, at 3.601 the focusing lens group starts to be driven toward the Far end, and at 3.802 the focusing lens group is being driven in the Far direction. , Far
The flag mark indicating the driving in the direction is set to 1, and a flag mark indicating that the focusing lens group is being driven is set at 3.603.

And at 8.604, the focusing lens group is Nea.
Add a flag mark indicating that it does not exist at the r end, S, 6C)
At step 5, a flag mark indicating that the focusing lens group does not exist at the Far end is added, and the process returns.

Next, the contents of the AF end point processing subroutine shown in FIG. 12 will be explained.

When entering the AF end point processing subroutine, 3. At 701, the AF stop subroutine (see FIG. 14) is executed, and at 3.702, the number of pulses dPX driven until the focusing lens group is stopped is calculated.

Then, in 3.703, it is determined whether the direction in which the focusing lens group was driven is the Far end direction, and if NO, in 3.704, it is determined whether the focusing lens group is extended from the Far end. Pulse number Pinf
Add dPX @ calculated in 8.702 to Pinf
and Pinf and Pnear (F a
The absolute value of the difference between the number of pulses from the r end to the Near end is defined as Pint (the number of pulses from the Near end); 3.
Proceed to 706.

In 3.706, it is determined whether Pint is smaller than e (the number of allowable error pulses, e.g. e=10), and if No, in 3.707 the focusing lens group is driven to the Near end side. subroutine (10th
Execute (Figure), and at 8.708, the AF pulse output interval is 1
00 m5ec or more.

If it is 100 m5ec or more, execute the focusing lens group AF stop subroutine (Fig. 14) at 3.709, and if it is less than that, repeat 8°708.
Wait until the end point is detected and proceed to 3.710.

On the other hand, if it is determined as YES at 3.708, it skips 8.707 to 709 and goes to 3.710 because it is within the predetermined error range.

In 3.710, a flag mark indicating that the focusing lens group exists at the Near end is added,
In S, 711, Pinf is rewritten to Pnear to eliminate accumulation of errors, and the process returns.

Also, if 3.703 is determined as YES, 5.71
2 to the number of pulses Pinf corresponding to the amount of extension of the focusing lens group from the Far end. 8. Subtract the dPX calculated in step 702 to obtain Pinf. Pin at 713
The absolute value of f is defined as Pint (the number of pulses to the N e a r end), and is set to 3.714.

In 3.714, the Pin
Determine whether t is smaller than e (tolerable error pulse number, e.g. e: 10), and if NO, 3.71
At step 5, a subroutine (FIG. 11) for driving the focusing lens group toward the Far end is executed, and the process proceeds to step 3.716.

In 3.718, the AF pulse output interval is 100
Determine whether it is 111 seconds or more, and if it is 100 m5ec or more, set 3.717 to AF of the focusing lens group.
The stop subroutine (FIG. 14) is executed, and if the value is less than that, 5.716 is repeated, and after detecting the end point, the process proceeds to 3.717.

On the other hand, if it is determined as YES at 3.714, it skips 3.715 to 717 and goes to 3.718, because it is within the predetermined error range.

In 3.718, the focusing lens group is Fa
3.719 with a flag mark indicating that it exists at the r end
Set Pinf: O to correct the origin and return.

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

When entering the AF drive stop subroutine, 3. At 801, the AF stop subroutine (see FIG. 14) is executed, and at 3.802, the number of pulses dPX driven until the focusing lens group is stopped is calculated, and the process proceeds to 3.803.

3. In 803, it is determined whether the direction in which the focusing lens group was being driven is the Far end side direction,
If NO, 3.804 is F of focus shift lens group.
The number of pulses Pinf corresponding to the amount of delivery from the ar end is 3.
．． Add the dPX calculated in 802 and get 8 as Pinf.
．． Proceed to 805.

3.805, Pinf is Pnear (F
a subroutine to drive the focusing lens group toward the Near end at 3.806 (Figure 10) 3.
Proceed to 807.

3.807, the AF pulse output interval is 100
Determine whether the end point has been reached based on whether it is greater than or equal to m5ec, and if it is greater than or equal to 100 m5ec, the rate is 3.80.
Execute the AF stop subroutine (Fig. 14) at 8 and proceed to 3.809, if less than 3.807
Repeat.

Then, at 3.809, a flag mark indicating that the focusing lens group exists at the Near end is added,
S, at 810, rewrite Pinf with Pnear and return.

On the other hand, if YES is determined in 3.803, the number of pulses Pinf corresponding to the amount of extension of the focusing lens group from the Far end is set to 3.802 in 3.811.
'? ' Subtract the calculated dPX to Pinf, S, 8
In step 12, it is determined whether Pinf is positive or not.

If YES, the process returns; if No, the subroutine (FIG. 11) for driving the focusing lens group toward the Far end is executed at 8°813, and the process proceeds to 3.814.

In 3.814, it judges whether the output interval of the AF pulse is 100 m5ec or more, as in 3.807 above.

If it is more than 100 tnsec, proceed to 8.815,
8. Execute the AF stop subroutine (Fig. 14).
Proceed to 818, and if it is less than that, repeat 8°814.

In 3.816, the focusing lens group is Fa
Add a flag mark indicating that it exists at the r end, S, 817
Set Pinf to 0 and return.

Next, the AF stop subroutine will be explained with reference to FIG.

When entering the AF stop subroutine, 3. At step 901, it is determined whether or not the focusing lens group is in AF driving. If YES, the process proceeds to 3.902; if NO, the process returns directly.

At 3.902, the driving of the focusing lens group is stopped, and at 3.903, a flag mark indicating that the driving of the focusing lens group is being stopped is added, and the process returns.

(Effects of the Invention) As described above, the present invention provides a photographic lens having a focusing lens group and a zooming lens group, and calculates the driving amount of the focusing lens group from the defocus amount and performs focusing based on the calculation result. It has a driving device for driving the lens group, and a focusing operation command output means for maintaining the state of the focusing lens group in the same state after focusing, and the output means for outputting the focusing operation command remains on. When the zooming lens group is moved, the driving amount of the focusing lens group is calculated again from the defocus amount, and the driving device is driven based on the calculation result.

Therefore, even if you zoom while the focus is locked after focusing, automatic focusing will be performed again to ensure that the image is in focus, thereby reliably preventing out-of-focus shooting. The degree of freedom in using the zoom lens is increased when determining the composition, etc.

[Brief explanation of drawings]

The drawings relate to embodiments of the present invention, and FIG. 1 is a block diagram showing the entire system, FIG. 2 is a circuit diagram inside the camera body, FIG. 3 is a circuit diagram inside the lens unit, and FIG.
The figure shows the power zoom drive check processing subroutine, Figure 5 is the main flowchart of automatic focusing in this system, Figure 6 is the initialization subroutine, and Figure 7 is the subroutine for power zoom drive check processing.
The diagram shows a subroutine for driving the zooming lens group toward the wide end, and FIG.
FIG. 9 is a subroutine for driving the zooming lens group toward the near end, FIG. 10 is a subroutine for driving the focusing lens group toward the near end, and FIG. 11 is a subroutine for driving the focusing lens group toward the far end. FIG. 12 shows a subroutine for AF end point processing, FIG. 13 shows a subroutine for stopping AF driving, and FIG. 14 shows a subroutine for stopping AF. L; Photographic lens, 5WSi output means (photometering switch), 10.11,
66; CPU. 60; Drive device.

Claims (1)

[Claims] a photographing lens having a focusing lens group and a zooming lens group; a driving device that calculates the driving amount of the focusing lens group from the amount of defocus and drives the focusing lens group based on the calculation result; and a means for outputting a focusing operation command to maintain the state of the group as it is, and when the zooming lens group is moved with the outputting means for the focusing operation command turned on, focusing is performed again from the defocus amount. An automatic focusing device for a camera having a zoom lens, which calculates a driving amount of a lens group and drives the driving device based on the calculation result.