JPH10170815A - Automatic focus detector for composite camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to detect focus with accuracy and without affecting both kinds of photographing, that is, video-photographing and still- photographing performed simultaneously, by controlling the camera so that the automatic focus detection for video photographing may be performed at the video-photographing time and the automatic focus detection for still- photographing may be performed when a still-photographing standby switch is turned on. SOLUTION: Signals from a video moving picture photographing trigger switch 34, the still-photographing standby switch 35a and a release switch 35b, etc., are always detected by a switch sense circuit so as to be transmitted to a mode microcomputer. And in the case the photographing standby switch 35a for the still-photographing switch 35 is turned on, the focus for still- photographing is detected. Next, whether it is focused or not is decided, when it is focused, a focused state is set. Since the focus for still-photographing whose focusing width is smaller than that of video-photographing is automatically detected after the start of preparing for still-photographing in such a way, photographing is accomplished in a focused state for both kinds of photographings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focus detecting device for a composite camera in which a still camera and a video camera for recording an image on a silver halide film are integrated.

[0002]

2. Description of the Related Art Conventionally, by integrating a still camera for recording a still image on a silver halide film and a video camera for recording a video moving image on a video tape, a composite camera capable of simultaneously obtaining a still image and a video image has been developed. For example, it is proposed in U.S. Pat. No. 2,838,601.

[0003] In the above-mentioned conventional compound camera, an image during video moving image shooting can be recorded as a still image on a silver halide film as needed, but the focus is more strictly controlled during still shooting than during video shooting. Therefore, in the above-described conventional compound camera, an optical system for increasing the depth of focus at the time of still photography is provided on the still camera side to cope with this.

[0004]

However, in the method of optically increasing the depth of focus on the still side as in the above-described conventional compound camera, the depth range on the still side and the range in which blurring is possible become narrow. When performing video shooting and still shooting at the same time, there is a problem that a clear still picture cannot be obtained because the video side is in focus but the still side is out of focus.

The present invention has been made in order to improve the disadvantages of the prior art, and does not affect the depth of focus on the still side. It is an object of the present invention to provide an automatic focus detection device of a compound camera which can perform focus detection without any influence (in focus).

[0006]

In order to achieve the above object, an automatic focus detection apparatus for a compound camera according to the present invention integrates a still camera using a silver halide film and a video camera and detects a focus for video shooting. Camera and a focus detection means for still photography, the video camera performs automatic focus detection by the video photography focus detection means and a still photography focus when the still photography preparation switch is turned on. Control means for controlling the detection means to perform automatic focus detection is provided.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a compound camera provided with an automatic focus detection device according to an embodiment of the present invention, and FIG. 2 is a plan view of the same. 1 and 2, reference numeral 1 denotes an exterior cover of a compound camera, 2 denotes a lens unit for capturing an image on a silver halide film 5, 3 denotes a lens barrel for holding a lens element constituting the lens unit 2, 4 Denotes an iris diaphragm for silver halide still photography, and 5 denotes a silver halide film. The lens unit 2 is a zoom lens, and is a focusing lens driven by information from a variable-magnification lens element group movable on the optical axis and information from an automatic focus detection device 15 described later in conjunction with an automatic or manual zoom operation. It is composed of an element group.

Reference numeral 6 denotes a shutter device disposed immediately before the silver halide film 5, which comprises a shutter curtain 6a, a shutter frame 6b, and the like. Reference numeral 7 denotes a translucent thin-film mirror for distributing images from the subject to the silver halide film 5 side and a solid-state image sensor 13 described later, 7a denotes an optical axis of light incident from the subject side, and 7b denotes a translucent thin-film mirror 7. Optical axes 7c and 7d which are transmitted and reach the silver halide film 5 side are optical axes reflected by the translucent thin film mirror 7. 8
Reference numerals a and 8b denote field lenses provided on the optical axis 7c to adjust the pupil of a subject image, 9 denotes a reflection mirror for deflecting the photographing optical axis 7c, and 10 denotes a reduction lens unit provided on the optical axis 7b. A video aperture unit 11 for capturing a video moving image is provided therein. Reference numeral 12 denotes an optical low-pass filter, and reference numeral 13 denotes a solid-state imaging device.

Reference numeral 14 denotes an aerial image formed at a position equivalent to that of the silver halide film 5, and is re-imaged on the solid-state image sensor 13 via the reduction lens unit 10.
A sub-mirror 14a is provided behind the translucent thin-film mirror 7 and is retractable during photographing. The sub-mirror 14a guides a part of photographing light to the automatic focus detecting means 15. The automatic focus detection means 15 employs a conventionally known phase difference deviation detection method, and compares a plurality of images generated by light beams passing through a plurality of different areas of the photographing lens to compare the images on the silver halide film 5 surface. The direction of the focus amount is detected. Reference numeral 16 denotes a light-shielding plate which can be retracted at the time of photographing in order to prevent light leakage caused by using the translucent thin-film mirror 7. Reference numeral 17 denotes a back cover unit which is provided to be freely opened and closed when the silver halide film 5 is loaded.

In this embodiment, a 135 type silver halide film is used. However, the present invention is not limited to this. Even if a film of a drop-in type or a disk type is used, there is no problem.

Reference numeral 18 denotes an electronic viewfinder unit which outputs an image to a small liquid crystal panel 19 to monitor an image signal from the solid-state image pickup device 13 and a reflection mirror 20.
And can be observed through the eyepiece 21. The electronic viewfinder unit 18 has a rotating shaft 22.
Can be turned around the support shaft.

On the other hand, during video moving image shooting, the iris diaphragm 4 for still shooting is always kept open, and when a release switch 35b for still shooting, which will be described later, is pressed down, the aperture is stopped down to a predetermined diameter. . Thus, during video movie shooting, the exposure is controlled only by the video aperture unit 11 in the reduction lens unit 10, and the appropriate exposure can be obtained by changing the accumulation time of the solid-state imaging device 13 and the gain of the signal processing system as necessary. It has become.

Reference numeral 23 denotes a secondary battery detachably attached to the inner bottom portion of the outer cover 1, serving as a common single power supply for supplying all the power used by the composite camera, and located in front of the lens unit 2. An openable / closable barrier 25 incorporating a strobe 24 is arranged. Reference numeral 26 denotes a microphone for recording audio during video shooting, and reference numeral 27 denotes an external terminal functioning as an interface for connecting an external device such as a television or a stereo device.

In FIG. 2, reference numeral 28 denotes a patrone chamber for the silver halide film 5; 29, a spool for winding the silver halide film 5; the last frame is wound up on the spool 29 before loading the film; It adopts a prewind system that rewinds sequentially. 30, 3
Reference numeral 1 denotes a zoom drive motor and a focus drive motor of the photographing lens. Reference numeral 32 denotes a zoom button arranged at a position operable by the photographer's right hand, 33 denotes a main mode selection switch also serving as a power switch, 34 denotes a video moving image shooting trigger switch, and 35 denotes a switch that operates in two steps. In the still shooting switch, in the still shooting, the first-stage switch 35a is ready for shooting, and the second-stage switch 35b works as a release, and can be used when shooting still alone and simultaneously shooting video moving images and still images. I have.

On the other side of the photographing system, a program exposure mode, a portrait mode using a wide open aperture, a sports mode giving priority to a shutter speed, a backlight mode, and the like can be selected and used in common for both moving picture and still photography. A mode selection dial 36 is provided.

On the other hand, the photometry for determining the exposure is feedback-controlled in accordance with the luminance signal level of the solid-state imaging device 13 for various modes.

Although the solid-state image pickup device 13 for video photographing is electrically divided into areas and used as photometric devices, a dedicated photometric device may be separately provided.

Reference numeral 37 denotes a video tape cassette storage unit disposed on the right side of the lens unit 2. In this embodiment, a video tape having a tape width of 8 mm is used as a video recording medium. The video cassette storage section 37 is provided with a recording mechanism including a magnetic head cylinder, a capstan, a pinch roller and the like (none of them are shown). And a control panel 38 for controlling the video tape, an eject button 39 for instructing an automatic loading operation of the video tape, and the like.

FIG. 3 is a block diagram showing a configuration of a control system of the composite camera configured as described above. In the figure, reference numeral 50 denotes a camera microcomputer composed of a microcomputer, which controls zooming of the lens unit 2 of the compound camera;
Auto focus control, automatic winding, exposure control, still photography control, and the like are performed.

Numeral 51 denotes a servo microcomputer comprising a microcomputer, which controls a mechanical part (recorder mechanical deck) 52 of the video recorder to record on a video tape and reproduce the video tape.

Numeral 53 denotes a mode microcomputer comprising a microcomputer, which determines a mode or the like in accordance with various types of switch information input from a switch sense circuit 61 to be described later, and sets the camera microcomputer 5 in accordance with the determined mode or the like.
0 and the servo microcomputer 51, and information such as a mode is sent to a liquid crystal display circuit 62 described later to perform display.

Numeral 54 is a lens control circuit, and numeral 55 is a zoom control circuit, which controls a distance ring and a zoom ring (neither is shown) of the lens unit 2 by a control signal sent from the camera microcomputer 50.

Reference numeral 56 denotes a film feeding circuit which controls film feeding such as winding of the silver halide film 5 one frame at a time or prewinding in accordance with a control signal from the camera microcomputer 51.

Reference numeral 57 denotes a focus detection unit constituting the automatic focus detection means 15, which comprises a plurality of line sensors corresponding to a screen and a drive circuit (neither is shown) for controlling the accumulation of these line sensors. Camera microcomputer 50
Receives the accumulated data (image signal of the subject) for each line sensor from the focus detection unit 55 and calculates the position where the subject is focused by the lens unit 2 using a known phase difference detection method. To detect.

Reference numeral 58 denotes a shutter control circuit which controls the shutter device 6 by a control signal sent from the camera microcomputer 50. An aperture control circuit 59 controls the video aperture unit 11 by a control signal sent from the camera microcomputer 50. Reference numeral 60 denotes a strobe light emission control circuit which controls the light emission and light control of the strobe light 24, a circuit for storing electric charge for light emission, a xenon tube as a light emitting portion, a trigger circuit, and a circuit for stopping light emission. And a film surface reflected light metering circuit and an integrating circuit (both not shown), and emits light when an X-contact (not shown) is turned on by a shutter film 6a of the shutter device 6.

Reference numeral 61 denotes a switch sensing circuit which constantly detects signals from the trigger switch 34 for video / moving image shooting, the switch 35a for still image shooting, the release switch 35b and the like, and sends them to the mode microcomputer 53.
Reference numeral 62 denotes a liquid crystal display circuit for displaying a remaining battery level, a mode, and the like in accordance with a command sent from the mode microcomputer 53. An audio control circuit 63 amplifies an audio signal from the microphone 26 and sends the amplified signal to the recorder mechanical deck 52 or the recorder mechanical deck 52.
The audio reproduced in step (1) is amplified and output to a speaker or the like (not shown). Reference numeral 64 denotes a digital signal processing circuit which processes a digital signal sent from the solid-state imaging device 13 and sends it to the recorder mechanical deck 52 and the like. 65 is a buzzer control circuit.

Next, the operation of the focus detection device of the compound camera configured as described above will be described with reference to the flowchart shown in FIG.

First, in step S401, it is determined whether or not the photographing preparation switch 35a of the still photographing switch 35 is turned on. If the switch 35a is turned on, the process proceeds to step S402, and the still-shot by the conventionally known phase difference method is performed. After performing focus detection for photographing, the process proceeds to step S404. If the shooting preparation switch 35a has not been turned on, the process proceeds to step S403. After performing focus detection for video shooting by a conventionally known blur method, the process proceeds to step S404.

In this step S404, it is determined whether or not the subject is in focus. If the subject is in focus, the flow advances to step S405 to set the focus, display the focus, etc., and end the automatic focus detection program (return). I do.

If the in-focus state is not obtained in step S404, the process proceeds to step S406. In the focus detection by the phase difference method, the camera microcomputer 50 calculates the lens driving amount based on the defocus amount, and obtains the obtained lens. After the control signal corresponding to the drive amount is output to the lens control circuit 54 and the lens unit 2 is driven so that the defocus amount is in focus, the automatic focus detection program ends. In step S406, in the focus detection of the blur method, the lens driving direction is determined based on the current focus detection result and the past focus detection result, and after the lens unit 2 is driven in the determined direction. Then, the automatic focus detection program ends.

With the above operation, at the start of the preparation for still photography, automatic focus detection can be performed with the in-focus range where still photography is possible.

[0033]

As described above in detail, according to the automatic focus detecting device for a composite camera of the present invention, after the preparation for still photography is started, the still photography for the still photography having a narrower focus width than the video photography focus width is performed. When performing video shooting and still shooting at the same time, the video shooting is in focus, but still shooting is not out of focus. This has the effect of making it possible to shoot images that have been shot.

If the preparation for still photography is not started, photography by automatic focus detection for still photography is not accepted, so that there is an effect that automatic focus adjustment optimal for video photography can be performed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a compound camera including an automatic focus detection device according to an embodiment of the present invention.

FIG. 2 is a plan view of the composite camera.

FIG. 3 is a block diagram showing a configuration of a control system in the composite camera.

FIG. 4 is a flowchart showing an operation of the automatic focus detection device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exterior cover 2 Lens unit 4 Still aperture iris diaphragm 5 Silver halide film 7 Translucent thin film mirror 10 Reduction lens unit 11 Video aperture unit 13 Solid-state image sensor 15 Automatic focus detection means 18 Electronic viewfinder 34 Video trigger button 35 Still photography Switch 50 camera microcomputer (control means) 51 servo microcomputer 53 mode microcomputer

Claims (1)

[Claims] 1. A composite camera in which a still camera using a silver halide film and a video camera are integrated and provided with a focus detecting means for video shooting and a focus detecting means for still shooting. And a control means for performing automatic focus detection by the focus detection means and controlling the automatic focus detection by the focus detection means for still photography when the still photography preparation switch is turned on. Automatic focus detection device.