JPH08205017A - Camera - Google Patents

Abstract

PURPOSE: To use an optical finder in response to the mode by providing a mode for usual focus adjustment by an automatic focus device and a mode hardly causing an out of focus. CONSTITUTION: A revision range of a focal distance of a zoom lens 10 is limited to be a prescribed zoom magnification by a zoom limit means and the drive range of a focal lens 106 by an automatic focus means is limited by a focus limit means. That is, when the conversion range of the focal distance of the zoom lens 10 is limited in the optical finder mode (mode hardly causing out of focus), the drive range of the focus lens 106 is limited within a prescribed range. Thus, when an image pickup distance is within a range of 1m to infinite, out of focus is not easily caused and the method is suitable in the case of using an optical finder 12 whose out of focus cannot be especially confirmed. Furthermore, the automatic focusing is made stable by limiting the drive range of the focus lens 106.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly to a video camera having a zoom lens and an autofocus device.

[0002]

2. Description of the Related Art An autofocus device for a video camera extracts a high frequency component of an image signal obtained through a photographing optical system and an image pickup device such as a CCD, and integrates and averages the extracted high frequency components to determine a focused state. An evaluation value for evaluation is obtained, and the focus lens is drive-controlled so that the evaluation value takes the maximum value, and focus adjustment is performed.

This system has many merits such that the image signal of the photographing screen can be used and the configuration of the lens and the like is simplified.

[0004]

However, when the shooting scene changes and the subject distance changes drastically, the focus direction (front focus or rear focus) cannot be known, and it is not possible to cope with a rapid change in the subject distance. , The focus is out of focus, and it may take time to focus.

The present invention has been made in view of the above circumstances. In addition to the normal focus adjustment mode using the autofocus device, a mode in which the focus is hard to blur is provided.
It is an object of the present invention to provide a camera capable of properly using these modes.

[0006]

In order to achieve the above object, the present invention provides a zoom lens, an autofocus means for driving a focus lens in the zoom lens for focus adjustment, and a focal length of the zoom lens. Limiting means for limiting the change range of the zoom lens to a predetermined zoom magnification or less, and when the change range of the focal length of the zoom lens is limited by the zoom limiting means, the focus lens is driven by the autofocus means. It is characterized in that it is provided with focus limiting means for limiting the range.

Further, the autofocus means is arranged to switch the drive speed of the focus lens to a low speed when the drive range of the focus lens is limited by the focus limiting means. Further, as the autofocus means, one that moves the focus lens to adjust the focus so that the integrated average value of the high frequency components of the image signal obtained via the zoom lens and the image sensor is maximized is used. . The autofocus means is restarted each time the zoom limit means limits or cancels the range of change of the focal length of the zoom lens.

Further, a monitor for displaying an image based on an image signal obtained through the zoom lens and the image pickup device, and an optical finder having a focal length change range smaller than a focal length change range of the zoom lens. , A switching means for selecting one of the mode using the monitor and the mode using the optical viewfinder, and the zoom limiting means is configured to change the mode using the optical viewfinder by the switching means. When selected, the changing range of the focal length of the zoom lens is limited to the changing range of the focal length of the optical viewfinder.

[0009]

According to the present invention, the zoom limiting means limits the range of change of the focal length of the zoom lens to a predetermined zoom magnification or less, and the focus limiting means limits the driving range of the focus lens by the autofocus means. I have to. That is, if the change range of the focal length of the zoom lens is limited, the focus is less likely to be out of focus, and if the drive range of the focus lens is limited to cover a predetermined shooting distance range, autofocus is stabilized. Therefore, when the subject to be photographed is limited to a certain degree and a subject within a predetermined photographing distance range is photographed, the above-mentioned restriction is provided, and even if there is a rapid change in the subject distance, the focus is hardly blurred. Or, even if the focus is slightly out of focus, the focus can be immediately adjusted by the autofocus means.

Further, when the drive range of the focus lens is limited, the drive speed of the focus lens is switched to a low speed, whereby the autofocus is made more stable. Furthermore, when using the optical viewfinder, it is not possible to check the out-of-focus state, so the condition is that the autofocus is stable and unblurred. Will be able to use.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a camera according to the present invention will be described below in detail with reference to the accompanying drawings. 1 and 2 are perspective views of the camera according to the present invention seen from the front side and the back side, respectively, and FIG. 3 is a plan view of the camera, each showing a state in which the liquid crystal monitor is opened.

This camera is a VTR with a built-in camera and has a thin rectangular parallelepiped external shape in the front-back direction of the camera (direction of arrow AB in FIG. 1). As shown in FIG. 1, a zoom lens 10, an optical viewfinder 12, and a stereo microphone 1
4 is attached to the upper part of the camera body. A liquid crystal monitor 16 is provided on the top of the camera body so as to be openable and closable. In addition, 18 is a VTR deck part to which an 8 mm cassette is attached and detached, 20 is a side grip part, and 22 is a photographing button.

The zoom lens 10 has, for example, a focal length of 3.3.
With a 10 × zoom zoom lens of mm to 33 mm, the focal length can be continuously changed electrically by operating the zoom button 24 (see FIG. 2). The optical finder 12 is, for example, a zoom finder for a 3 × zoom, and at least within a range in which the focal length can be adjusted, the focus of the zoom lens 10 is changed according to the change of the focal length so that the shooting range and the visual field range match. The distance is adjusted. The details of the zoom lens 10 and the optical finder 12 will be described later.

The VTR deck unit 18 includes a rotary head drum, a tape loading mechanism, a tape feeding mechanism, etc., which are not shown, and outputs a video signal indicating a subject photographed by the zoom lens 10 and an audio signal detected by the stereo microphone 14 to the video signal. Magnetic recording and playback on videotapes of millimeter cassettes. Reference numeral 26 is a cassette lid which is opened and closed when the cassette is inserted and taken out.

The side grip portion 20 is formed in a shape that can be gripped by the right hand, and the finger grip portion 30 is provided on the front surface of the camera.
As shown in FIG. 2, a concave portion 32 in which the thumb and the base of the thumb are located is formed on the back surface of the camera. The shooting button 22 is provided on the front surface of the camera and is operated by the index finger of the right hand holding the side grip 20. Further, the zoom button 24 is arranged at a position where it can be operated by the thumb of the right hand.

On the other hand, as shown in FIG. 2, on the back surface of the camera, a liquid crystal display section 34 is disposed adjacent to the lower side of the eye cup of the optical viewfinder 12, and a battery 36 is mounted below the liquid crystal display section 34. Has been done. Further, a monitor opening / closing button 38, a power switch 40, a remote control light receiving section 42, etc. are provided. Further, a diopter adjustment knob 44, a battery eject button 46, and a cassette eject button 48 are provided on the side of the camera body.

By the way, the liquid crystal monitor 16 functions not only as a monitor during image reproduction but also as a finder during photographing.
It is arranged to be openable and closable through 6A and electrically connected, and is formed so as to be flush with each surface of the camera body when closed. Further, when the liquid crystal monitor 16 is opened, the operation panel section 50 provided on the top of the camera body is exposed as shown in FIG. 3, and various button groups can be operated. Reference numeral 52 is a shooting button (double / single) switch, 54 is a negative film (off / on) switch, 56 is a sports mode (off / on) switch, 5
8 is a monitor (off / on) switch, 60 is a brightness control knob, 62 is a volume control knob, 64 is a speaker, 66 is a mode switch button for switching between a camera mode and a VTR mode, and 68 is a playback in the VTR mode or the like. ,Stop,
A group of buttons for instructing fast forward, rewind, etc. Also, 7
Reference numeral 0 is a lock hole into which the lock claw 16B on the liquid crystal monitor side is inserted.

Next, the zoom lens 10 and the optical finder 12 will be described in detail. As shown in FIG. 4, the zoom lens 10 is mainly a front lens (fixed lens).
100, variator lens 102, fixed lens 104,
The variator lens 102 and the focus lens 10 are composed of a focus lens 106 and a focus lens 106.
6 are guided by guide rods 110 so as to be movable in the optical axis direction.

The variator lens 102 includes a zoom motor 112, gears 114 and 116, and a zoom cam 118.
The focus lens 106 is driven in the optical axis direction by the driving force transmitted via the focus lens 120.
Driven in the optical axis direction by the driving force transmitted from the lead screw 122 and the nut 124. The zoom motor 112 is normally or reversely driven according to the operation of the zoom button 24. That is, as shown in FIG. 6, when a signal indicating the tele direction or the wide direction is input from the zoom button 24 to the camera control microcomputer 130, the camera control microcomputer 130 sends the zoom signal to the zoom motor via the zoom driver 132. 112 to drive the zoom motor 112 forward or backward. By driving the zoom motor 112, the variator lens 102 moves forward or backward in the optical axis direction. The variator lens 102
Is detected by the zoom encoder 134, and the zoom position (focal length of 3.3 mm to 33 mm) is added to the camera control microcomputer 130 by an 8-bit signal of 0 to 255. (Fig. 7
reference).

On the other hand, the focus motor 120 is driven according to the position (zoom position) of the variator lens 102 and the subject distance. That is, the focus lens 106
Is driven so that the subject image scaled by the variator lens 102 is formed on an image pickup device (hereinafter referred to as CCD) 140 such as CCD, and the lens position is formed to form the best image by the contrast method. Driven.

Here, the control of the focus lens 106 will be described in detail. First, the position of the focus lens 106 can be detected by the output of the home position sensor 136 that detects the home position of the focus lens 106 and the number of pulses to the focus motor (pulse motor) 120. That is, the home position sensor 136 is necessary for forming the subject image on the CCD 140 when the focus lens 106 is at the home position (this home position is at infinity and the variator lens 102 is at the wide end). When the focus lens 106 is reached, the detection signal is output to the camera control microcomputer 130. The camera control microcomputer 130 counts the number of pulse signals output to the focus motor 120 via the focus driver 134 based on the position at which the detection signal is input from the home position sensor 136, and from the count value, the focus lens 106 is counted. The position of is being detected. still,
As shown in FIG. 7, the count value of the pulses given to the focus motor 120 is the home position (pulse number =
0) to 340 pulses.

Further, as shown in FIG. 7, the camera control microcomputer 130 determines the position of the focus lens 106 with respect to each zoom position (positions represented by 0 to 255) for each object distance of infinity, 1 m, and 10 mm. It has a look-up table indicating the number of pulses), and the look-up table is used to control the focus lens 106 so that the focus lens 106 is at a required position according to the position (zoom position) of the variator lens 102.

That is, when the focus lens 106 is stopped at the solid line (a curve indicating infinity) in FIG. 7 by the autofocus described later and zooming is performed thereafter, the focus lens 106 moves along the solid line. 1
06 is controlled. Similarly, if zooming is performed while stopped at the alternate long and short dash line (curve showing 1 m),
The focus lens 106 is controlled to move along the alternate long and short dash line, and when zooming is performed while stopped at the dotted line (curve indicating 10 mm), the focus lens 106 is controlled to move along the dotted line. Further, when the focus lens 106 is at a position other than the above curve, the focus lens 106 is controlled so as to trace on a curve where the ratio between the position and each curve is constant.

The above is the focus lens 1 during zooming.
The control of the focus lens 106 when the focus adjustment is performed has been described above.
The subject light imaged on the light receiving surface of the CCD 140 via the zoom lens 10 is accumulated in charge by each sensor for a predetermined time,
The signal charges are converted into an amount corresponding to the intensity of light. The signal charges thus accumulated are read out to the shift register by a read gate pulse of a predetermined cycle applied from a CCD drive circuit (not shown), and sequentially read out as an image signal by a register transfer pulse.

The image signal read from the CCD 140 in this manner is used as the AGC circuit 142 and the A / D converter 1.
After being converted into a 10-bit digital image signal via 44, the liquid crystal monitor 1 via a signal processing circuit (not shown).
6 and the VTR deck unit 18, and is also output to the high-pass filter unit 148 and the photometric unit 150 via the bit compression unit 146 that performs non-linear compression to 8 bits.

The high-pass filter section 148 extracts the high-frequency component of the input digital image signal, and the evaluation value calculation section 15
2, the evaluation value calculation unit 152 calculates the evaluation value for evaluating the in-focus state by integrating and averaging the input signals, and outputs the evaluation value to the camera control microcomputer 130. Then, the camera control microcomputer 130 controls the focus lens 106 so that the input evaluation value is maximized. When the evaluation value becomes maximum in this way, the focus adjustment by the focus lens 106 is completed. When the evaluation value changes by a certain amount or more, it is determined that the scene has changed and the above-described autofocus is restarted.

The photometric section 150 detects the screen brightness from the input digital image signal and outputs a signal indicating the screen brightness to the camera control microcomputer 130. The camera control microcomputer 130 controls the iris 105 via the iris driver 136 and the iris meter 138 so that the screen brightness becomes a predetermined brightness. The opening of the iris 105 is detected by the iris sensor 139, and a signal indicating the opening is sent to the camera control microcomputer 13
It has been added to 0. If the screen brightness cannot be controlled by the iris 105, the camera control microcomputer 130 outputs a control signal to the AGC circuit 142 to control the gain of the image signal.

Next, the optical finder 12 will be described. As shown in FIG. 5, the optical finder 12 mainly includes an objective lens 160 facing a subject, a front zoom lens 162 and a rear zoom lens 1 for changing a focal length.
64, an appropriate fixed lens 166, and an eyepiece lens 168. These lenses are arranged inside a substantially L-shaped finder cylinder 170.

The objective lens 160 is fixed to the tip of the finder cylinder 170. Behind the objective lens 160, the front zoom lens 162 is provided with the front lens frame 1.
The rear zoom lens 164 is held by the mount portion 172A of the rear lens 72 and the rear zoom lens 164 is mounted on the mount portion 1 of the rear lens frame 174.
It is held at 74A. A guide rod 176 is provided on the side of the front zoom lens 162 and the rear zoom lens 164 substantially parallel to the direction of the optical axis S, and the guide rod 176 is supported by the side wall of the finder barrel 170. . The lens frames 172 and 174 are slidable cylinders 172B and 174B on the sides of the mount portions 172A and 174A.
Are integrally connected to each other, and the sliding cylinders 172B and 174B are inserted into the guide rod 176. Further, guide protrusions 172C and 174C are formed on the side portions of the mount portions 172A and 174A, and are engaged with a guide hole 170A formed in the side wall of the finder cylinder. The sliding cylinders 172B and 174B are provided with engaging protrusions 172D and 174D as engaging portions. Further, a tension spring 178 is stretched to connect the sliding cylinders 172B and 174B to each other, and the lens frames 172 and 174 are biased toward each other.

On the other hand, a cam shaft 180 which is substantially parallel to the guide rod 176 is provided adjacent to the guide rod 176, and the cam shaft 180 is rotatably supported on the side wall of the finder barrel 170. A substantially cylindrical zoom cam 182 is fitted to the cam shaft 180, and cam surfaces 182A are formed at both ends of the zoom cam 182. The lens frames 172, 17 are provided on the cam surface 182A.
The four engaging protrusions 172D, 174D are in contact with each other, and the engaging protrusions 172D, 174D are arranged along the cam surface 182A.
Is being guided. Here, the front zoom lens 162
The rear zoom lens 164 and the rear zoom lens 164 maintain a predetermined optical relationship so that the focal length is changed, and when the zoom cam 182 further rotates beyond the maximum magnification, the maximum magnification is maintained. A cam surface 172A is formed (see FIG. 4).

One end of the cam shaft 180 is projected to the outside of the finder cylinder 170, and a gear 184 is fitted therein. The gear 184 is linked to the rotary shaft of the zoom motor 112 via gears 114 and 116 as shown in FIG. For this reason, as will be described later, the change in the focal length of the optical viewfinder 12 and the change in the focal length of the zoom lens 10 are configured to substantially coincide with each other up to 3 × zoom. On the other hand, a field frame plate 186 is arranged behind the rear zoom lens 164, and a reflecting mirror 188 that bends the optical axis S is provided at a corner of the finder cylinder 170. The fixed lens 166 is arranged beside the reflecting mirror 188, and the finder shutter 190 is arranged at an appropriate position.

The finder shutter 190 is composed of a shutter plate 192 having a substantially flat plate shape, and a rotary shaft 192A is formed at the upper end side of the shutter plate 192. The rotating shaft 192A is rotatably supported by a notch 170B on the side wall of the finder cylinder 170. One end of the rotating shaft 192A is projected outside the finder cylinder 170 to form a lever portion 192B. There is. That is, the shutter plate 192 is substantially perpendicular to the optical axis S and blocks the optical path to close the shutter, and the shutter plate 192 jumps substantially parallel to the optical axis S to release the optical path and release the shutter. It is freely rotatable in the open state.
In addition, a return spring 1 by a winding spring is attached to the rotating shaft 192A.
94 is provided to urge the shutter plate 192 in the closing direction.

The lever portion 192B includes a lever 196.
The lower end portion 196A of the lever 196 is engaged, and the upper end portion 196B of the lever 196 is pressed by the lock claw 16B of the liquid crystal monitor 16 in the direction indicated by the arrow A. Therefore, when the liquid crystal monitor 16 is closed, the lever 196 is moved to the position shown in FIG.
The shutter plate 192 is rotated counterclockwise around the support shaft 196C, and the shutter plate 192 is flipped up and opened against the spring biasing force. On the other hand, when the liquid crystal monitor 16 is opened, the shutter plate 192 is closed by the urging force of the return spring 194.

A mode changeover switch 198 is provided facing the upper end portion 196B of the lever 196,
Similarly to the above, the liquid crystal monitor 16 is turned on / off according to opening / closing. The mode changeover switch 198 is a switch for selecting either a normal mode using the liquid crystal monitor 16 or an optical viewfinder mode using the optical viewfinder 12, and when the liquid crystal monitor 16 is opened. The normal mode is set, and when the liquid crystal monitor 16 is closed, the optical viewfinder mode is set.

In accordance with these modes, the electric circuit connected to the control device of the camera body is intermittently connected. That is, the LCD monitor is turned on in the normal mode,
In the optical viewfinder mode, the liquid crystal monitor is turned off. Therefore, the optical viewfinder mode is a power saving mode, and is also a pan focus mode in which the focus is hard to be blurred as described later.

In this embodiment, the finder shutter 190 is mechanically opened / closed according to the opening / closing operation of the liquid crystal monitor 16, but the mode changeover switch 198 or another switch appropriately operated by the photographer. A motor or the like may be used to open and close the finder shutter. A prism 199 that bends the optical axis S at a substantially right angle is housed at the base end of the finder barrel 170. The eyepiece lens 168 is arranged so as to face the exit surface of the prism 199.
Further, a dead space is formed by the L-shaped finder cylinder 170. The dead space is provided with the stereo microphone 14, the switch board (not shown) of the operation panel unit 50, etc. Is being used effectively.

Next, the limitation of the range of change of the focal length of the zoom lens 10 and the limitation of the drive range of the focus lens 106 due to the switching between the normal mode and the optical viewfinder mode will be described. The variable focus lens device of the zoom lens 10 is a 10 × zoom, and the liquid crystal monitor 1
In Fig. 6, the images of all the focal lengths of the changed range can be confirmed, whereas the variable focus lens device of the optical finder 12 has the 3x zoom, and therefore the focal length of all the focal lengths of the zoom lens 10 is changed. It is not possible to capture images at almost the same angle of view.

Therefore, the range of change of the focal length of the zoom lens 10 can be varied from 0 to 255 as shown in FIG. 7, but when switched to the optical viewfinder mode, it is reduced to 24 to 162, and the optical range is changed. Expression finder 12
Adjust to the change range of the focal length of. That is, when the camera control microcomputer 130 is switched to the optical viewfinder mode by the mode switch 198, the lens movement mechanism of the zoom lens 10 is restricted as described above.

In the normal mode, when the zoom lens 10 is driven beyond the 3 × zoom, the engagement protrusions 172D and 174D of the lens frames 172 and 174 of the optical viewfinder 12 are the cams of the zoom cam 182. Face 18
It comes to be located in the flat portion of 2A, so that even if the zoom cam 182 rotates, the front zoom lens 162 and the rear zoom lens 164 remain stationary in the 3 × zoom state. Then, when the zoom lens 10 is in a state of exceeding the 3x zoom when the normal mode is switched to the optical viewfinder mode, the zoom lens 10 is immediately returned to the 3x zoom and the optical viewfinder is selected. 12
Matched with the magnification of.

By the way, the drive range for adjusting the focus of the focus lens 106 becomes smaller as the zoom lens 10 has a lower magnification, as shown in FIG. Therefore, if the change range of the focal length of the zoom lens 10 is limited as described above, the drive range for the focus adjustment of the focus lens 106 can be reduced, and the shooting distance is, for example, 1 m to infinity. In some cases, the drive range for focus adjustment of the focus lens 106 becomes smaller, and the drive range of the focus lens 106 is about 10 pulses as the number of drive pulses to the focus motor 120 even in the case of the 3 × zoom. .

Therefore, when the optical finder mode is switched to and the range of change of the focal length of the zoom lens 10 is limited, the drive range of the focus lens 106 is also limited within a certain range, as shown by the hatched lines in FIG. . In this range, the number of pulses applied to the focus motor 120 from the position of the focus lens 106 at infinity is 10
It is within the pulse range.

By limiting the drive range of the focus lens 106 in this way, when the shooting distance is in the range of 1 m to infinity, the focus becomes difficult to blur, and in particular, the blur of the focus cannot be confirmed. It is suitable when using a finder. Also, the focus lens 1
By limiting the driving range of 06, the autofocus is also stabilized. That is, since the focus is hard to be out of focus, a good focus evaluation value can be obtained at the time of autofocusing, and the focus direction (front focus or rear focus) is not lost, and as a result, the focus is quickly adjusted. .

Furthermore, in this embodiment, the focus lens 106 is switched to the optical viewfinder mode.
The drive speed of is also switched to low speed to make autofocus more stable. Furthermore, when switching from the normal mode to the optical viewfinder mode,
Alternatively, when the optical viewfinder mode is switched to the normal mode, the autofocus is restarted.

When photographing a negative film,
In the front of the zoom lens 10, a negative film photographing device including a close-up lens, a film carrier, a backlight, etc. is attached, and a negative film switch 54
Is set to “ON”, but in this case as well, the change range of the focal length of the zoom lens 10 is limited as shown in FIG. 7. The operation of the embodiment of the camera according to the present invention configured as described above will be described below.

When the photographer turns on the power switch 40 of the camera, the photographer stands by in a photographable state. Then, the subject image passes through the zoom lens 10 and is captured by the CCD 140. When the mode changeover switch 198 is set to the normal mode, that is, when the liquid crystal monitor 16 is in the open position as shown by the solid line in FIG. 6, the image is displayed on the liquid crystal monitor 16. Therefore, the photographer can take a picture while checking the image on the liquid crystal monitor 16.

In this normal mode, the shutter plate 192 is substantially perpendicular to the optical axis S by the urging force of the return spring 194 as described with reference to FIG. Therefore, the optical path of the optical viewfinder 12 is blocked and the viewfinder shutter 190 is closed, and the photographer cannot see the subject image even when looking through the optical viewfinder 12.

By the way, when the mode selector switch 198 is switched to the optical viewfinder mode when the battery capacity is low, the liquid crystal monitor 16 is set to the closed position as shown by the broken line in FIG. To do. The lever 1 is interlocked with the closing operation of the liquid crystal monitor 16.
96 rotates, the mode switch 198 is switched to the optical viewfinder mode by the lever 196, and the shutter plate 192 bounces against the biasing force of the return spring 46 via the lever portion 192B of the shutter plate 192. The shutter plate 192 is raised to be in a state substantially parallel to the optical axis S, and the blocking of the optical path is released. Then, the subject image is transmitted through the objective lens 160, the front zoom lens 162, the rear zoom lens 164, the fixed lens 166, the eyepiece lens 168, etc., and is captured by the photographer.

Further, by switching the mode selector switch 198 to the optical viewfinder mode, the electric circuit is disconnected and the liquid crystal monitor 16 is turned off. Therefore, the photographer views the subject image only with the optical finder 12. Here, the photographer selects the zoom button 24
When is operated, the zoom motor 112 is driven, and as shown in FIG. 4, the zoom cam 118 on the zoom lens 10 side is driven.
And the zoom cam 182 on the optical finder 12 side rotate at the same time.

When the zoom cam 118 on the zoom lens 10 side rotates, the variator lens 102 moves back and forth to change the magnification of the subject image, and the focus lens 106 is controlled according to the position (zoom position) of the variator lens 102 to bring the focus into focus. It will not come off. When the zoom cam 182 on the optical finder 12 side rotates, the front zoom lens 162 and the rear zoom lens 164 are moved while maintaining a predetermined optical relationship, and the focal length of the optical finder 12 is changed. .

In this way, the zoom lens 1 described above is used.
The change of the focal length of 0 and the change of the focal length of the optical finder 12 are substantially coincident with each other. As described above, in the optical viewfinder mode, the zoom lens 10
The range in which the focal length of the lens is changed and the drive range for adjusting the focus of the focus lens 106 are limited. Further, when the zoom lens 10 is in a state of exceeding the 3x zoom when the normal mode is switched to the optical viewfinder mode, the zoom lens 10 is immediately returned to the 3x zoom and the optical viewfinder is selected. Matched with a magnification of 12.

[0051]

As described above, according to the camera of the present invention, in addition to the normal focus adjustment mode by the autofocus device, a mode in which the focus is less likely to be out of focus is provided. You can use the finder. In other words, when using the optical viewfinder, it is not possible to check the out-of-focus state, so the condition is that the autofocus is stable and out of focus. Will be able to use. Further, when the optical finder is used, it is not necessary to use a liquid crystal monitor or the like, and the liquid crystal monitor is also turned off to save power. Further, by limiting the drive range of the focus lens, it is possible to avoid parallax in the short-distance shooting of the optical viewfinder and the zoom lens.

[Brief description of drawings]

FIG. 1 is a perspective view of a camera according to the present invention as viewed from the front side.

FIG. 2 is a perspective view of a camera according to the present invention viewed from the back side.

FIG. 3 is a plan view of the camera shown in FIGS. 1 and 2.

4 is a partial cross-sectional view of a zoom lens and an optical finder of the camera shown in FIG.

5 is a perspective view showing a structure of an optical finder of the camera shown in FIG.

FIG. 6 is a block diagram of an essential part of a camera according to the present invention.

FIG. 7 is a graph used to explain the range of change of the focal length of the zoom lens and the limitation of the drive range of the focus lens.

[Explanation of symbols]

 10 ... Zoom lens 12 ... Optical viewfinder 14 ... Stereo microphone 16 ... Liquid crystal monitor 16B ... Lock claw 102 ... Variator lens 106 ... Focus lens 112 ... Zoom motor 118, 182 ... Zoom cam 120 ... Focus motor 130 ... Camera control microcomputer 140 ... CCD 162 ... Front zoom lens 164 ... Rear zoom lens 170 ... Viewfinder barrel 190 ... Viewfinder shutter 192 ... Shutter plate 194 ... Return spring 196 ... Lever 198 ... Mode selection switch

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03B 13/36

Claims (8)

[Claims] 1. A zoom lens, an autofocus means for driving a focus lens in the zoom lens to adjust a focus, and a focal length change range of the zoom lens is limited to a predetermined zoom magnification or less. Zoom limiting means, and focus limiting means for limiting the drive range of the focus lens by the autofocus means when the range of changing the focal length of the zoom lens is limited by the zoom limiting means. And the camera. 2. The camera according to claim 1, wherein the autofocus means switches the drive speed of the focus lens to a low speed when the drive range of the focus lens is restricted by the focus restriction means. 3. The autofocus means moves the focus lens to adjust a focus so that an integrated average value of high frequency components of an image signal obtained via the zoom lens and the image pickup device is maximized. 1 or 2 cameras. 4. The autofocusing means restarts the focus adjustment each time the zoom limiting means limits or cancels the range of change of the focal length of the zoom lens. 3 cameras. 5. A monitor that displays an image based on an image signal obtained through the zoom lens and the image sensor,
An optical finder having a focal length changing range smaller than a focal length changing range of the zoom lens, and switching means for selecting one of a mode using the monitor and a mode using the optical finder. The zoom limiting unit limits the change range of the focal length of the zoom lens to the change range of the focal length of the optical viewfinder when the mode in which the optical viewfinder is used is selected by the switching unit. Claims 1, 2, 3 or 4
Camera. 6. The zoom limit when the mode in which the optical finder is used is selected by the switching means when the focal length of the zoom lens is changed beyond the range of changing the focal length of the optical finder. The camera of claim 5, wherein the means matches the focal length of the zoom lens with the current focal length of the optical viewfinder. 7. The zoom lens performs correction and focus adjustment of an image forming position by varying the magnification of a subject image by a variator lens by the focus lens, and the focus limiting means sets each zoom position when the subject distance is infinity. 6. The camera according to claim 1, wherein the position of the focus lens set in advance is limited within a fixed movement range. 8. The zoom lens performs correction of an image forming position by variable magnification of a subject image by a variator lens and focus adjustment by the focus lens, and the autofocus means includes a pulse motor for driving the focus lens, The focus limiting means limits the number of pulses to be applied to the pulse motor from a preset position of the focus lens at each zoom position when the subject distance is infinity within a fixed value. 2, 3, 4 or 5 cameras.