JPH0879605A - Image pickup device - Google Patents

Abstract

PURPOSE: To dissolve parallax without using a complicated mechanism in an image pickup element having a optical viewer frame system different from an image pickup optical system. CONSTITUTION: The image pickup device having the image pickup optical system 1 and the optical viewer frame system 5 independent of the image pickup optical system 1 is provided with the image pickup element 2, a subject distance detection means 6 detecting distance information showing a distance to a subject based on the position of a focus lens group in the image pickup optical system, an image pickup system distance information detection means 8 detecting image pickup focal distance information showing the focal distance of the image pickup optical system, a finder system distance information detection means 7 detecting viewer frame system focal distance information showing the focal distance of the viewer frame optical system 5 and a video signal selection means 9 segmenting a part of a video signal from the image pickup element based on the detection results of the subject distance detection means 6, the image pickup system distance information detection means 8 and the viewer frame system distance information detection means 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus having an image pickup optical system and a finder optical system independent of the image pickup optical system.

[0002]

2. Description of the Related Art There are roughly two types of viewfinders in image pickup devices. One is an electronic system that displays the signal from the image sensor on a small CRT, etc., and the other is a viewfinder optical system that is separate from the imaging optical system.
It is an optical system that shows the subject image through this.

FIG. 4 shows an example of an optical system. The light passing through the image pickup optical system 1 is photoelectrically converted into a video signal by the image pickup element 2. The video signal is processed by the video signal processing circuit 3 and then recorded on a recording medium such as a magnetic tape by the recording circuit 4. A finder optical system 5 is provided separately from the image pickup optical system 1, through which a photographer can see a subject image being photographed.

In the case of this system, the image from the image pickup optical system 1 is different from that from the finder optical system 5 because the optical axis of the image pickup optical system 1 is different from that of the finder optical system 5. Parallax occurs, and the effect of the parallax becomes large especially when the subject is close.

An example of parallax is shown in FIG. The figure shows the case where the viewfinder optical system is located above the imaging optical system and the printed matter at a short distance is photographed. That is, when the photographer is looking at the image in FIG. 5a from the finder optical system, the imaging optical system is displaced by the distance between the optical axes of both optical systems.
Is shooting the image of b.

In order to solve this problem, conventionally, a correction frame for short-distance photographing is provided in the finder, and the direction of the finder optical system is changed according to the distance to the subject. However, the corrected frame has a drawback that the photographer has to judge the frame according to the distance, which causes many oversights and shooting mistakes. Further, the method of automatically changing the direction of the finder optical system has a drawback that the mechanism becomes complicated, which is disadvantageous in terms of size and cost.

[0007]

The conventional measures against parallax in an optical viewfinder, which makes accurate framing difficult especially for an object at a short distance, is required to completely prevent operation mistakes, size, and cost. There are challenges in terms.

It is an object of the present invention to eliminate parallax in an image pickup device having a finder optical system in addition to the image pickup optical system without using a complicated mechanism.

[0009]

In order to solve the above problems, the present invention provides an image pickup device having an image pickup optical system and a finder optical system independent of the image pickup optical system, and an image pickup element and the image pickup optical system. A subject distance detecting means for detecting distance information indicating a distance to a subject based on a position of a focus lens group in the inside, and an imaging system distance information detecting means for detecting imaging system focal length information indicating a focal length of the imaging optical system. A finder system distance information detecting unit for detecting finder system focal length information indicating a focal length of the finder optical system, based on detection results of the subject distance detecting unit, the imaging system distance information detecting unit, and the finder system distance information detecting unit. And a video signal selecting means for cutting out a part of the video signal from the image pickup device.

[0010]

[Operation] The shooting range of the image pickup system is set large in advance by the amount including the parallax shift, and at the time of shooting, the range seen from the viewfinder is calculated from the distance to the subject and the focal length of the optical system. The range is cut out by the video signal selection circuit.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the same parts as those of the above-described conventional technique are designated by the same reference numerals and the description thereof will be omitted. FIG. 1 is a functional block diagram of an image pickup apparatus which is a first embodiment of the present invention. In the figure, the output of the video signal processing circuit 3 is once shown by the image memory 1
Stored at 0. On the other hand, from the imaging optical system 1, the subject distance detection circuit 6 can obtain information on the subject distance based on the position of the focus lens, for example.

In this embodiment, a so-called zoom mechanism having a variable focal length is assumed as the optical system. Here, the focal lengths of the image pickup optical system 1 and the finder optical system 5 change in conjunction with each other, and the image entering the image pickup device 2 has a wider angle with respect to the image seen by the photographer through the finder optical system 5. Has been done. Further, the finder system focal length detection circuit 7 and the image pickup system focus detection circuit 8 can obtain information on the focal lengths of both optical systems based on the position of the variable power lens, for example. Then, the information on the subject distance and the focal length is sent to the video signal selection circuit 9, and the circuit calculates the area on the video signal corresponding to the image on the finder. The video signal selection circuit 9 cuts out the corresponding area from the image memory 10 and outputs it to the recording circuit 4.

Next, the operation of this embodiment will be described with reference to FIG. An image as shown in FIG. 2A is obtained from the finder optical system 5, and an image as shown in FIG. 2B is obtained from the imaging optical system 1 which is shifted upward due to parallax and has a wider angle. The video signal selection circuit 9 calculates an area shown by a dotted line in FIG. 2B and controls the image memory 10 to expand and output this area as a whole screen as shown in FIG. 2C. As a result, the same image as the photographer sees is sent to the recording circuit 4 through the finder optical system 5.

Further, a second embodiment of the present invention is shown in FIG. In the second embodiment, the same operation is realized by controlling the read position from the image sensor 2 without using the image memory. That is, based on the control signal from the video signal selection circuit 9, the image pickup device drive circuit 11 reads out only the signal in the appropriate region from the image pickup device 2.

[0015]

According to the present invention, it is possible to provide an image pickup apparatus which solves the parallax problem of the optical viewfinder without using a complicated mechanism, and the effect is great.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the first embodiment.

FIG. 3 is a functional block diagram showing a second embodiment of the present invention.

FIG. 4 is a functional block diagram showing a conventional technique.

FIG. 5 is an explanatory diagram illustrating a problem of a conventional technique.

[Explanation of symbols]

 1 Imaging Optical System 2 Imaging Device 3 Video Signal Processing Circuit 5 Viewfinder Optical System 6 Subject Distance Detection Circuit 7 Viewfinder System Focal Length Detection Circuit 8 Imaging System Focal Distance Detection Circuit 9 Video Signal Selection Circuit 10 Image Memory 11 Imaging Device Drive Circuit

Claims (1)

[Claims] 1. An image pickup apparatus having an image pickup optical system and a finder optical system independent of the image pickup optical system, comprising: an image pickup element; and a distance indicating a distance to a subject based on a position of a focus lens group in the image pickup optical system. Subject distance detection means for detecting information, imaging system distance information detection means for detecting imaging system focal length information indicating the focal length of the imaging optical system, and finder system focal length information indicating the focal length of the finder optical system. Finder system distance information detecting means for detecting, image signal selection for cutting out a part of the image signal from the image sensor based on the detection results of the subject distance detecting means, the image capturing system distance information detecting means, and the finder system distance information detecting means And an image pickup device.