JPS62141862A - Finder device for single-lens reflex camera - Google Patents

Abstract

PURPOSE:To monitor clearly both a still photograph image and photograph information displayed at the surrounding of the pattern by forming the image of the still photograph image so as to be smaller than a video photograph image and arranging a display device in a finder so as to form the image of the still photograph information. CONSTITUTION:Since a video optical system from a penta prism 4 provided in a finder device 300 to a master lens 6 is formed that the photodetection plane of an image pickup element 8 is a video photograph image 8a with an aspect ratio of 3:4, the still photograph image 8b formed on a focus plate 2 of a camera main body 100 having an aspect ratio of 2:3 is formed by the video optical system so that the image is smaller than the video photograph image 8 of the photodetection plane. A display device 12 in the finder is placed via a reflection prism 11 at the left upper position of the penta prism 4 as shown in broken lines corresponding to a vacant space in the photodetection plane of the image pickup element in order to form the image of display of still photograph information such as shutter speed, aperture or photograph mode.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a finder device for a single-lens reflex camera having a built-in image sensor for a video camera.

(Background of the Invention) Conventionally, in a single-lens reflex camera that uses a remote control method,
A radio-controlled unit for remote control is installed on the camera, and after looking through the viewfinder and setting the copying range to a predetermined range, the user can monitor the situation from a distance from the camera installation position, seize the photo opportunity, and use remote control to capture the photo opportunity. I try to take still pictures.

However, when shooting stills using such remote control, you can only see the image in the viewfinder, which can cause you to miss the timing of copying, or to set the framing to capture the subject at the appropriate position within the image. In many cases, this is not possible, and since it is not possible to move too far from the shooting location, a considerable amount of patience is required for copying, and it is difficult to make effective use of the few photo opportunities.

Therefore, by attaching a general video camera to the eyepiece part behind the eyepiece of the viewfinder, we projected the video camera's monitor image onto a TV set far from the shooting location, and then remotely shot still images while looking at the monitor image. A system in which photography is performed is being attempted.

However, when the video camera is attached to the eyepiece portion of the finder, the video camera is attached to the rear of the camera, which increases the size and makes handling inconvenient.

Therefore, it has been considered that an image sensor for a video camera is built into a finder device with a freely replaceable membrane for the camera body of a -1 reflex camera. By forming an image on the camera, it is possible to use it as a video monitor for remote shooting.

(Problems to be Solved by the Invention) By the way, in the monitor display of a single-lens reflex camera that uses a finder device with a built-in image sensor for a video camera, the aspect ratio (vertical and horizontal) of the still shooting screen in the finder In the case of 35 mm digital film, the ratio is 2:3, whereas the aspect ratio of the video (to) shadow screen on the light receiving surface of the image element for a video camera is 3:3.
:4, and taking into account the difference in aspect ratio between the two, for example, the still shooting screen is imaged on the light receiving surface of the image sensor by the video optical system so that the width of the video shooting screen matches the width of the still shooting screen. I try to let them do it.

On the other hand, around the still photography screen in the finder, an in-finder display device using liquid crystal or the like displays various still photography information related to photography, such as shutter speed, aperture value, and exposure compensation mark.

However, due to the difference in aspect ratio between the still shooting screen and the video shooting screen, for example, even if the image is formed on the image sensor so that the width of the still shooting screen matches the width of the video shooting screen, the still @ Akira information in the viewfinder is Since the display position of is not set in consideration of the aspect ratio of the video screen, the still shooting information (displayed in the viewfinder) may be displayed on the monitor in a cut-off state.To prevent this, a still shooting screen is required. The still pupil shadow information around the reduced size would be imaged on the video shooting screen of the image sensor, and there was a risk that the monitor display of the still shooting screen would become too small.

Furthermore, the video optical system that forms an image of the still shooting screen in the viewfinder on the image sensor is equipped with an auto iris mechanism to keep the amount of light incident on the image sensor constant.
Therefore, if the shooting screen is bright compared to the display brightness of the shooting information displayed around the still shooting screen, the auto iris will narrow down the amount of incident light for the shooting information, and display enemy shadow information such as shutter speed and aperture value on the monitor screen. There was also the problem that it could not be confirmed.

(Objective of the Invention) The present invention has been made in view of the above-mentioned problems in the prior art, and uses a video camera image sensor built into the viewfinder to clearly display both the still shooting screen and the shooting information displayed around it. An object of the present invention is to provide a finder device for a single-lens reflex camera that can display images on a monitor.

(Summary of the Invention) In order to achieve this object, the present invention provides a viewfinder device for a single-lens reflex camera with a built-in image sensor for a video camera, in which a still shooting screen with an aspect ratio of 2:3 is used as a video optical system. The image is formed to be smaller than the video shooting screen with an aspect ratio of 3:4 on the light-receiving surface of the image sensor, and the shutter speed and The technical key point is that the display device in the viewfinder is arranged so that still photography information such as aperture value is displayed.

(Embodiment) FIG. 1 is an explanatory diagram showing an embodiment of the present invention installed in a single-lens reflex camera.

First, to explain the configuration, 100 is the camera body of a single-lens reflex camera, and a normal interchangeable photographic lens 20 is mounted on the front.
0 is attached, the light from the photographing lens 200 is reflected upward by the quick return mirror 1 provided on the camera body 100, and a still ratio image is formed on the focus plate 2.
A still photographed image of the focus plate 2 is taken out by the condenser lens 3 and made incident on a removable finder device 300 of the present invention installed on the upper part of the camera body 10. A film 15 is arranged behind the quick return mirror 1, and by reversing the quick return mirror 1 with a shutter release, a subject image formed by the photographing lens 200 is formed on the film surface.

The finder device 300 of the present invention, which is attached to the top of the camera body 100, has a pentaprism 4 at a position opposite to the condenser lens 3 on the camera body 100 side, and the still image of the focus plate 2 incident on the pentaprism 4 @ A video camera @mechanical element 8 is mounted on a video camera board 9 through a pair of mask lenses 6 having an auto iris 7 between them and reflecting the chromatic screen upward with a roof prism 5.
The still shooting screen is imaged on the light-receiving surface of the camera. As the dynamic image element 8 for this video camera, a solid state dynamic image element such as a COD in which a large number of light-receiving pixels are two-dimensionally arranged is used. Further, the video camera board 9 includes a built-in video circuit that converts the light reception signal obtained from the drive circuit of the enemy device 8 and the i-device device 8 into a predetermined television system, for example, an NTSC signal, and outputs the signal to the outside. ing.

On the other hand, an in-finder display device 12 for displaying still photography information such as shutter speed, aperture value, and exposure compensation mark is installed at the upper left of the pentaprism 4 via a reflective prism 11. As the display device 12 in the finder, for example, a liquid crystal display device is used that displays photographing information by receiving transmitted light from illumination light.Therefore, behind the display device 12 in the finder, there is a diffuser plate 13 that creates a surface light source. A lighting device 14 is disposed through the video camera board 9, and the lighting device 14 operates as an illumination light source by receiving a DC voltage from a lighting drive circuit provided on the video camera board 9.

Next, in the embodiment shown in FIG.
The function of the video optical system for displaying a still shadow screen and photographing information from the finder display device 12 on the light receiving surface of the image sensor 8 provided in the camera will be explained with reference to FIG.

FIG. 2 shows an optical image formed on the light receiving surface of the dark image element 8, and this optical image is displayed as it is on the monitor screen. That is, in the video optical system from the pentaprism 4 provided in the finder device 300 to the master lens 6, the light receiving surface of the image element 8 shown in FIG. 2 is a video solid screen 8a with an aspect ratio of 3:4. Therefore, the aspect ratio of the image formed on the focus plate 2 of the camera body 100 is 2:
3 is formed by a video optical system so as to be smaller than the video eye shadow screen 8a on the light-receiving surface.

Specifically, since the size of the methyl@chromatic screen imaged on the focal plate 2 and the serrations of the video shooting screen on the light-receiving surface of the imaging element 8 are physically determined, the image shown in FIG. As shown in FIG.
The still photographing screen 8b is formed by determining the magnification of the video optical system that accommodates the still photographing screen 8b.

When the still photographing screen 8b is imaged by the video optical system so as to be smaller than the video solid screen 8a,
Empty spaces can be created above, below, and to the left and right of the still shadow screen 8b imaged on the video solid screen 8a.

However, in order to form an image of the still@color screen 8b with the maximum space within the video shooting screen 8a, the still shooting screen 8 should be arranged so that it approximately matches the width of the video shooting screen 8a.
Since image b is formed, empty spaces are mainly formed above and below the still eye shadow screen 8b.

Therefore, in the empty space formed above and below the still shooting screen 8b, @machine element is used to display still shooting information such as the shutter speed, aperture value, or shooting mode on the viewfinder display device 12. An in-finder display device 12 is installed via a reflective prism 11 at the upper left position of the pentaprism 4, which is indicated by a broken line and corresponds to the empty space on the light-receiving surface of 8.

The video optical system provided in such a finder device 300 forms an image of a still photographing screen 8b as shown in FIG. By arranging the display device 12 in the finder that forms an image of the photographing information 8c in an empty space, the image sensor 8 built into the finder device 300 displays a still photographing screen and still photographing information such as shutter speed, aperture value, and photographing mode. can be displayed on a video monitor with appropriate screen layout.

Next, control of the display brightness of the in-finder display device 12 will be explained.

FIG. 3 is a schematic block diagram showing the control circuit of the illumination device 14 that adjusts the display brightness of the display device 12 in the viewfinder together with the video circuit of the image sensor 8. The optical image shown in FIG. 2 formed on the image sensor 8 such as a CCD is
By driving the image sensor 8, the light reception signal is read out and given to the process circuit 17, where it is subjected to predetermined signal processing, and then sent to the matrix circuit 18 and the encoder 19.
For example, the signal is output to a monitor television as an NTSC signal. On the other hand, the video signal of the still photographing screen 8b obtained by the process circuit 17 is given to the auto iris control circuit 20, and a detection voltage corresponding to the amount of incident light is determined by a video detection signal or the like.

The auto iris control circuit 20 adjusts the aperture opening of the auto iris 7 so that the light amount detection voltage becomes the crotch T reference voltage, and adjusts it so that a preset constant amount of light incident on the image sensor 8 can be obtained. On the other hand, the video signal from the process circuit 17 is also given to a DC voltage control circuit 21, and the DC voltage control circuit 21 applies a DC control voltage to the illumination device according to the amount of light incident on the image sensor 8 determined by video detection or the like. 14, and the intensity of the illumination light is changed according to the amount of light incident on the image sensor 8. Note that when the auto iris 7 is activated, the amount of light incident on the image sensor 8 is kept at a constant amount; Holds the amount of incident light before activation,
The brightness of the lighting device 14 is now controlled. On the other hand, since there is a predetermined inverse proportional relationship between the aperture amount of the auto iris 7 by the auto iris control circuit 20 and the amount of incident light, the DC voltage control circuit 21 controls the illumination so that the characteristic is inverse to the auto iris control circuit 20. The device 14 may also be controlled.

In this way, by changing the intensity of the illumination light from the illumination device 14 in accordance with the amount of incident light from the subject, the shutter speed and aperture value that are imaged on the light receiving surface of the image sensor 8 can be adjusted as shown in FIG. The still shooting information displayed on the display device 12 in the finder, etc. always has approximately the same display brightness as the still shooting screen 8b, and the still shooting information displayed on the display device 12 in the finder at the same time as the still shooting screen 8b regardless of changes in the brightness of the subject. The photographing information 8c can be clearly displayed on the monitor screen, and even if it is a remote pupil shadow, the remote shutter release can be appropriately performed while checking the still photographing information on the display device 12 in the viewfinder as in normal photographing. be able to.

(Effects of the Invention) As described above, according to the present invention, in a finder device of a single-lens reflex camera that incorporates a copying element for a video camera, a still shooting screen with an aspect ratio of 2:3 can be used as a video optical system. The image is formed to be smaller than the video shooting screen with an aspect ratio of 3:4 on the light-receiving surface of the image sensor, and the shutter is placed in the empty space around the still shooting screen that is imaged on the image sensor by the video optical system. Since the display device in the viewfinder is arranged so that still shooting information such as speed and aperture value is displayed, even if the aspect ratios of the still shooting screen and video shooting screen are different, this difference in aspect ratio will be minimized. By making effective use of this feature, you can create a still shooting screen and a video shooting screen with still shooting information displayed on the display device in the viewfinder. Instead, you can use a television monitor to conduct a suitable remote viewing.

Furthermore, since the display brightness of still image information on the display device in the viewfinder changes to the optimal brightness by following the brightness of the subject, the monitor screen displays shutter speed, aperture value, etc. at the same time as the still image screen. Still copying information can be clearly displayed, and appropriate remote still copying can be performed while checking the still copying information displayed on the monitor screen.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention mounted on a single-lens reflex camera, Fig. 2 is an explanatory diagram of an optical image formed on an image sensor, and Fig. 3 is an implementation of Fig. 1. FIG. 2 is a schematic block diagram showing a circuit for adjusting display brightness of an in-finder display device in an example together with a video circuit. 100: Camera body 200: Copying lens 300: Finder device 1: Quick return mirror 2: Focus plate 3: Condenser lens 4: Pentaprism 5: Roof prism 6: Mask lens 7: Auto iris 8: Image sensor (for video camera) 9 : Video camera board 10: Film 11: Reflection prism 12: Viewfinder display device 13: Diffusion plate 14: Illumination device 16: Driver 17: Process circuit 18: Matrix circuit 19: Encoder 20 Niord iris control circuit 21: DC voltage control circuit

Claims (2)

[Claims] (1) In a finder device of a single-lens reflex camera with a built-in image sensor for a video camera, a video optical system that images a still shooting screen with an aspect ratio of 3:2 within the imaging range of the image sensor; 1. A finder device for a single-lens reflex camera, comprising: an in-finder display device arranged so as to image still photography information in an empty space of a still photography screen imaged by an optical system on an image sensor. (2) The viewfinder of a single-lens reflex camera according to claim 1, wherein the finder display device includes means for changing display brightness so that the brightness is optimal depending on the still shooting screen. Device.