JPH04304781A - Multi-focus still video camera - Google Patents

Abstract

PURPOSE:To realize a multi-focus camera by using plural CCDs. CONSTITUTION:An optical path L of one optical system 2 is divided into two optical paths L1, L2 by a beam splitter 3 and 1st and 2nd CCDs 4, 5 with a different size are arranged to an image forming face of the optical paths L1, L2. Thus, the larger 1st CCD 4 picks up the entire object at a large picture angle theta to attain wide angle image pickup. Moreover, the smaller 2nd CCD 5 picks up the middle of the object at a small picture angle theta' to attain telescopic pickup.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multifocal still video camera using a plurality of CCDs.

0002

[Prior Art] A still video camera captures an image with a CCD through an optical system, converts the image information into an electrical signal, and records it on a recording medium such as a floppy disk. The camera itself can be made smaller.

0003

[Problem to be Solved by the Invention] However, in recent years, there has been a demand for cameras to have multiple focal points (wide-angle, telephoto), and if this was addressed by an optical system, the size of the camera would increase due to the increase in the size of the optical system. This goes against the demand for miniaturization. In view of these circumstances, it is an object of the present invention to provide a still video camera that uses a plurality of CCDs to achieve multifocal focus.

0004

[Means for Solving the Problems] Therefore, the present invention provides C
In a still video camera that captures images using a CD, the optical path of one optical system is divided into multiple optical paths, and CCDs of different sizes are arranged on the imaging plane on each optical path to configure a multifocal still video camera. . Alternatively, a multifocal still video camera is constructed by providing a finder optical system having at least two imaging planes and arranging CCDs of different sizes on the conjugate plane of each imaging plane.

Alternatively, a finder optical system having at least two image-forming surfaces is provided, a CCD is arranged on the conjugate plane of each image-forming surface, and the magnification of the relay lens between the image-forming surfaces is set to non-equal magnification. Configure a focus still video camera.

[0006]

[Operation] In the above configuration, from the CCDs of different sizes arranged on the image forming plane on each divided optical path,
Image signals with different angles of view can be obtained. That is, an image with a large angle of view (a wide image with a short focal length) can be obtained from a large CCD, and an image with a small angle of view (a telephoto image with a long focal length) can be obtained from a small CCD.

[0007] Furthermore, by using a finder optical system having at least two image-forming surfaces and arranging CCDs of different sizes on the conjugate plane of each image-forming surface, the finder optical system can be shared with the imaging optical system. It is possible to realize multi-focus while In addition, by using a finder optical system having at least two image-forming surfaces, placing a CCD on the conjugate plane of each image-forming surface, and making the magnification of the relay lens between the image-forming surfaces non-equal, While using CCDs of the same size, it is possible to realize multi-focus while sharing the finder optical system with the imaging optical system.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the invention. The camera includes an aperture 1, an optical system 2, a beam splitter (or half mirror) 3 that splits the optical path L of the optical system 2 into two optical paths (straight, downward) L1 and L2, and a straight optical path L1.
A first CCD 4 is disposed on the image plane of the downward optical path L2, and a second CCD 5 is disposed on the image plane of the downward optical path L2.

Here, the first CCD 4 and the second CCD 5 are different in size, the first CCD 4 being a relatively large one, for example, a 1/2 inch type, and the second CCD 5 being a relatively small one, for example, a 1/3 inch type. shall belong to. According to this, the large first CCD 4 can image the entire subject with a large angle of view θ, making wide-angle photography possible. On the other hand, the small second CCD 5 can image the central part of the subject with a small angle of view θ', making telephoto shooting possible.

In this way, by dividing one optical system 2 into two optical paths L1 and L2 and arranging CCDs 4 and 5 of different sizes on the imaging planes on each optical path L1 and L2, the difference in angle of view can be reduced. It is possible to create a zoom effect. In this example, the zoom ratio M is M=θ/θ'≒(1/2
)/(1/3)=1.5.

The lens of the optical system 2 may be designed in accordance with the first CCD 4 on the wide-angle side, thereby improving aberrations on the telephoto side. Reading during recording is performed by the first CCD4 and the second CC
D5 results in reverse reading. The images to be recorded can be selected by the photographer, but simultaneous recording is also possible. Instead of the beam splitter (or half mirror) 3, a movable mirror may be used so that selection can be made by its rotational position.

In addition, in such a multifocal camera having a plurality of CCDs, when photographing is performed using one CCD 4 (or 5), the other CCD 5 (or 4) performs autofocus (AF) using a video signal without time lag. ), photometry (
AE) can also be performed. Further, when performing direct photometry using a CCD as a photometry element, it is preferable to change the photometry area according to the angle of view.

That is, as shown in FIG.
D on the software, photometry area A for 1/2 inch CCD
and photometry area B for 1/3-inch CCD installed therein.
It is preferable to divide the area into two, or further divide the area into three by providing a spot photometry area C within the area B. FIG. 3 shows a second embodiment.

In this embodiment, the finder optical system is also used as the imaging optical system. The finder optical system is
This is a secondary imaging type physical finder that is composed of an objective lens 11, a relay lens 12, and an eyepiece lens 13, and has a first imaging plane F1 and a second imaging plane F2 between them. 14 indicates an eyepiece. Here, the first imaging plane F
Movable mirrors 15 and 16 are arranged in front of each of the first and second imaging planes F2, and a first
A first CCD 17 and a second CCD 18 are arranged at conjugate positions of the imaging plane F1 and the first imaging plane F2, respectively.

[0015] Here, the first CCD 17 and the second CCD 18
The first CCD 17 is relatively large, and the second CCD 18 is relatively small. According to this, by moving the movable mirrors 15 and 16 in and out, images can be taken by any one of the first and second CCDs 17 and 18. Specifically, by inserting the movable mirror 15 onto the optical path, the large first CCD 17 can image the entire subject at a large angle of view, making wide-angle photography possible. Also, if the movable mirror 16 is inserted onto the optical path, a small second
The CCD 18 allows the central part of the subject to be imaged with a small angle of view, making telephoto shooting possible.

[0016] By using a beam splitter or a half mirror instead of the movable mirrors 15 and 16, the same effect can be obtained and simultaneous imaging is also possible. Moreover, instead of making the first and second CCDs 17 and 18 different in size, a bifocal camera can be realized by setting the magnification of the relay lens 12 to a non-equal magnification. FIG. 4 shows a third embodiment.

This embodiment uses a liquid crystal display (LCD).
) etc. is reflected by a movable mirror 20 arranged behind the second imaging plane L2 (or first imaging plane L1) and guided to the eyepiece 14 side via the eyepiece lens 13. This is what I did. Thereby, by moving the movable mirror 20 in and out, the eyepiece 14 can selectively observe the optical image and the image on the monitor 19. Note that a beam splitter or a half mirror may be used instead of the movable mirror 20.

FIG. 5 shows a fourth embodiment. In this embodiment, the second image forming surface L2 (or the first image forming surface L1
), by inserting and removing the monitor 21 such as an LCD, the eyepiece 14 can be used to observe the optical image and the monitor 2
This allows the user to selectively observe the first image. The advantages of using the configuration shown in FIG. 4 or 5 are as follows.

Finders used in still video cameras can be roughly divided into ordinary optical finders and electronic finders using LCDs and the like. Since electronic viewfinders require a powerful battery as they require monitor output to an LCD etc. during observation, optical viewfinders are generally used because of their clear and easy-to-see nature. There are many.

[0020] Conventionally, however, in order to realize an optical finder, a finder optical system is required in addition to the imaging optical system, so the structure tends to become complicated. In this respect, in the embodiment shown in FIG. 4 or 5, since the imaging optical system and the finder optical system share the same optical system, the configuration is relatively simple, and moreover, the optical finder and the electronic finder can be switched. can be used.

[0021]

[Effects of the Invention] As explained above, according to the present invention, image signals with different angles of view can be obtained from a plurality of CCDs of different sizes, and wide-angle photography and telephoto photography are possible with one optical system. This effect can be obtained. Also, at least 2
By using a finder optical system with two imaging planes and arranging CCDs of different sizes on the conjugate plane of each imaging plane, the finder optical system can be shared with the imaging optical system to simplify the process. This has the effect of realizing multi-focus.

[0022] Furthermore, a finder optical system having at least two image-forming surfaces is used, and a CCD is disposed on the conjugate plane of each image-forming surface, and the magnification of the relay lens between the image-forming surfaces is made non-uniform. As a result, while using CCDs of the same size, the viewfinder optical system can be shared with the imaging optical system, simplifying the system, and achieving multi-focus.

[Brief explanation of drawings]

[Fig. 1] Schematic diagram showing the first embodiment of the present invention

[Figure 2
] Diagram showing an example of photometric area division when using a CCD as a photometric element

[Figure 3] Schematic diagram showing the second embodiment

[Figure 4] Schematic diagram showing the third embodiment

[Figure 5] Schematic diagram showing the fourth embodiment

[Explanation of symbols]

2 Optical system 3 Beam splitter 4 1st CCD 5 2nd CCD 11 Objective lens 12 Relay lens 13 Eyepiece lens 14 Eyepiece 15, 16 Movable mirror 17 1st CCD 18 2nd CCD 19 Monitor 20 Movable mirror 21 Monitor

Claims (3)

[Claims] Claim 1: In a still video camera that captures images using a CCD, the optical path of one optical system is divided into a plurality of optical paths,
A multifocal still video camera characterized in that CCDs of different sizes are arranged on the imaging plane on each optical path. 2. A still video camera that captures images using a CCD, characterized in that a finder optical system having at least two image-forming surfaces is provided, and CCDs of different sizes are arranged on a conjugate plane of each image-forming surface. Multifocal still video camera. 3. A still video camera that captures images using a CCD, a finder optical system having at least two image forming surfaces, a CCD disposed on a conjugate plane of each image forming surface, and a relay lens between the image forming surfaces. A multifocal still video camera characterized by having a non-equal magnification.