JP2001281751A - Single lens reflex camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single lens reflex camera capable of easily performing focusing even when strict focusing is required. SOLUTION: This single lens reflex camera is equipped with a focusing screen 4 provided with a split image prism 4a at the center part and finder optical systems (5, 8 and 9) for optically observing a subject image formed on the screen 4. In the camera, the subject image on the screen 4 is picked up by an image pickup device 11 arranged in the optical path of a finder optical system, and the range of one part of the screen 4 including the prism 4a is displayed on a monitor device 12 based on data picked up by the device 11. An image part (center part of the focusing screen) necessary for focusing is enlarged and displayed on a monitor screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-lens reflex camera, and more particularly to a single-lens reflex camera which is effective when strict focus adjustment is required, such as in macro photography.

[0002]

2. Description of the Related Art A viewfinder optical system of a general single-lens reflex camera is configured such that a subject image light beam having passed through a taking lens is reflected by a movable mirror to form a left-right inverted image on a focusing screen. In this configuration, an erect erect image is formed via a pentaprism and observed through an eyepiece. This is the same as watching the focusing screen at a certain distance with a loupe. In most cases of a manual focus adjustment camera (manual focus camera), a split image prism as a focus adjustment assisting optical member is disposed at the center of the focusing screen.

As shown in FIG. 6, the split image prism (hereinafter, referred to as a split image) has two semicircular wedge-shaped bracelets which are inclined in opposite directions and are arranged vertically. The intersection of the two wedge prisms is the focus plane. For example, when observing one line, when the intersection is focused in front (front focus) or when the back is focused (back focus). If so, the two images on the upper and lower wedge prisms are displaced as shown in FIGS. 7B and 7C. On the other hand, if the image is in focus on the focus plane, the upper and lower images become one line as shown in FIG. If the photographer adjusts the focus of the photographing lens by operating a distance ring or the like so as to eliminate the displacement of the upper and lower images, a photograph in focus can be taken.

[0004]

However, in the conventional single-lens reflex camera, the range occupied by the split image portion in the viewfinder screen is very small in the center, so that strict focus adjustment such as macro photography is required. It was difficult and unsatisfactory to focus on the required subject photography.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a single-lens reflex camera which can easily perform focus adjustment even when strict focus adjustment is required.

[0006]

According to the first aspect of the present invention,
In a single-lens reflex camera including a focusing screen for forming an image of a subject and a finder optical system for optically observing the subject image on the focusing screen, the focusing lens is provided in an optical path of the finder optical system. An image pickup means for picking up a subject image on a screen; and a display means for displaying the subject image based on a subject image signal picked up by the image pickup means, wherein the subject displayed on the display means is provided. The image displays only a part of the subject image observed by the finder optical system.

According to the first aspect, only a part of the subject image formed on the focusing screen is displayed on a liquid crystal display or the like having a fixed screen size, so that the displayed image is substantially a viewfinder. This is an enlarged image of a part of the subject image observed by the optical system. Focusing can be performed while observing the enlarged display image, so that it is easy to precisely perform focus adjustment.

According to a second aspect of the present invention, in the single-lens reflex camera according to the first aspect, the range displayed by the display means is around a focus adjustment assisting optical member provided on a focusing screen. It is characterized by.

According to the second aspect of the present invention, a peripheral image including a focus adjustment assisting optical member such as a split image or a microprism used on a focusing screen used in a manual focus camera is enlarged and displayed. The mismatch will be clearly visible.

According to a third aspect of the present invention, there is provided a focusing screen provided with a focus adjustment assisting optical member at a central portion, and a finder optical system for optically observing a subject image formed on the focusing screen. A single-lens reflex camera comprising: an imaging unit for imaging a subject image on the focusing screen; and a part on the focusing screen including the focus adjustment assisting optical member based on data captured by the imaging unit. And display means for displaying the range.

According to the third aspect of the present invention, a partial area including a focus adjustment assisting optical member such as a split image or a micro prism provided at the center of the focusing screen is enlarged and displayed on a monitor. Will be clearly visible.

[0012]

Embodiments of the present invention will be described with reference to the drawings. [First Embodiment] FIG. 1 is a conceptual diagram showing a configuration of a single-lens reflex camera to which the present invention is applied.

In FIG. 1, a subject image light beam passes through a photographing lens 1 and an aperture mechanism 2 and is reflected by a movable mirror 3 to form an image on a focusing screen 4.

The photographer 13 can observe the subject image formed on the focusing screen 4 through the pentaprism 8 and the condenser lens 5 by looking through the eyepiece 9.

The split image 4a described above is arranged in the center of the focusing screen 4, in an area of about 1% in terms of area ratio. Also, split image 4
The range other than a is a normal mat surface. If the subject is out of focus, the subject image is blurred. If the subject is focused, a clear subject image can be observed. If the photographer adjusts the focus of the photographing lens 1 so as to eliminate the shift between the two images in the split image, the subject can be appropriately focused.

Behind the movable mirror 3, a focal plane shutter 7 and a silver halide film 6 are arranged. When a release button (not shown) is operated, the movable mirror 3 is turned around the rotation shaft 3a as shown by an arrow in the figure. While rotating, it retracts out of the photographing optical path, and the focal plane shutter 7 is opened for a set time to expose the silver halide film 6.
When the exposure operation is completed, the movable mirror 3 moves down again to guide the subject image light beam to the finder optical system.

If the photographer wants to strictly adjust the focus, the two images on the split image may be too small. A mechanism for solving such a problem will be described below.

A finder mirror 14 is arranged between the exit surface 8a of the pentaprism 8 and the eyepiece 9 so as to be movable in the observation optical path and outside the optical path. The finder mirror 14 is rotated about an axis of rotation 14a as shown by an arrow in the figure.

During normal object observation, the finder mirror 14 is retracted outside the observation optical path, that is, upward in the drawing. If the photographer wants to adjust the focus more strictly, the operation member 15 is operated. The operation member 15 is a rotation operation member, and
Mechanically connected to And this operation member 15
Is rotated by a predetermined angle in a predetermined direction, the finder mirror 14 can be moved from the inside of the observation optical path to the outside of the optical path or from the outside of the optical path to the inside of the optical path by a connecting mechanism (not shown).

When the finder mirror 14 is in the observation optical path, the observation image light flux emitted from the pentaprism 8 is reflected upward in the drawing, and is reflected by the imaging lens 10 onto the imaging surface of the imaging device 11 as imaging means. It is imaged.

The imaging device 11 is a device that captures an image on a focusing screen and generates electronic image data. However, what is imaged by the imaging device 11 is a partial range of the subject image on the focusing screen, specifically, a partial range including the split image 4a.

FIG. 2 shows the configuration of the image pickup device 11. The imaging device 11 includes, for example, an imaging device 17 such as a CCD, and an image signal captured by the imaging device 17.
2 and an image processing circuit 18 that performs signal processing so that the image can be displayed on the display 2. A switch input circuit 16 for outputting an ON (ON) or OFF (OFF) detection signal based on a rotation operation of the operation member 15 is provided, and the image processing circuit 18 performs signal processing based on the switch detection signal. You can get started.

An electronic image picked up by the image pickup device 11 is displayed on a monitor device 12 as a display means such as a liquid crystal display device. The monitor device 12 is a display unit having a constant screen size, for example, disposed on the back side of the camera housing. As described above, since the electronic image captured by the imaging device 11 is only a part of the observation image on the focusing screen, when this electronic image is displayed on the entire screen of the monitor device 12, substantially only the periphery of the split image 4a is enlarged. Will be displayed.

This will be described with reference to FIGS. 3 (a) and 3 (b). FIG. 3A shows an observation image when looking through the eyepiece unit 9, and the split image portion 4 a covers about 1% of the center of the screen. If the image is out of focus, the two images on the split image are out of alignment.
The surrounding mat surface is blurred. Imaging device 1
1 captures an area 16 indicated by a dotted line in FIG. 3B, that is, a peripheral area including the split image 4a. Then, an enlarged image as shown in FIG. 3C is displayed on the monitor device 12.

Here, the features of this camera are summarized as follows: (1) When the photographer operates the operation member 15 in order to perform more accurate focus adjustment and confirmation of the focus adjustment state, the finder mirror 14 moves out of the observation optical path. Move into the optical path from

(2) As a result, the observation image light beam is
It is led to one.

(3) The image pickup device 11 picks up an observation image, that is, a part of the subject image formed on the focusing screen 4, and converts it into an electronic image.

(4) The electronic image is displayed on the monitor device 12. The display image at that time is an image obtained by substantially enlarging the periphery of the split image 4a.

(5) Since the split image portion 4a is enlarged, the photographer can perform more precise focus adjustment while viewing the displayed image.

Next, the operation of the imaging device 11 and the monitor device 12 shown in FIG. 2 will be described with reference to the flowchart of FIG.

The photographer turns the operation member 15 from the OFF position to O.
When the rotation operation is performed to the N position, the finder mirror 14 advances into the observation optical path as described above, and the operation state is detected by the switch input circuit 16. The detection result is sent to the image processing circuit 18 in the imaging device 11.

The image processing circuit 18 has a function of controlling the operations of imaging, image processing and display. When a signal indicating that the operating member 15 has been operated to the ON side is received from the switch input circuit 16, The operation shifts from the stop state to the operation state, and the operation shown in the flowchart of FIG. 3 is started.

First, an imaging start instruction signal for starting an imaging operation is sent to the imaging device 17 (S1).
Then, it waits for an imaging completion signal from the imaging device 17 (S
2) When the signal is received, the image signal is read, and digital image data is created after analog / digital conversion (A / D conversion) (S3). Subsequently, a process of converting the digital image data into a form suitable for display is performed (S4),
The digital image data is sent to the monitor device 12, the display instruction signal is sent to the monitor device 12, and the image data is displayed on the monitor device 12 (S5). next,
The state of the switch by the operating member 15 is checked (S
6) If the operation member 15 is at the ON position, the process returns to S1. That is, the moving image is continuously displayed on the monitor device 12 in real time. When the operation member 15 is returned to the OFF position again, the process proceeds to S7, and after the end processing (transmission of a stop signal to the image sensor 17 and the monitor device 12) is performed, the operation is stopped.

[Second Embodiment] FIG. 5 shows a second embodiment of the present invention.
FIG. 3 is a diagram showing a main part configuration in the embodiment. 5, parts having the same functions as those in FIG. 1 are denoted by the same reference numerals. In FIG. 5, only the components different from those in FIG. 1 are shown, and other components are omitted.

In the first embodiment, since the finder mirror 14 is arranged between the exit surface 8a of the pentaprism 8 and the eyepiece 9, the size of the eyepiece may be increased. is there. In addition, during monitor display, the finder mirror 14 advances into the observation optical path, so that there is a disadvantage that optical observation using the finder becomes impossible.

Therefore, in the second embodiment shown in FIG. 5, the finder mirror 14 is eliminated and the pentaprism 8
The final reflecting surface 8b of the half mirror (reflectance about 70%)
A part of the observation image light beam that has passed through the half mirror 8b passes through the imaging lens 10 and passes through the imaging device 1 in the imaging device 11.
7, the observer 13 can observe the entire screen through the finder optical system (reference numeral 9 is an eyepiece), and can observe an enlarged image on the display screen of the monitor device 12. . However, since 30% of the finder observation light beam is guided to the imaging device 11 through the half mirror of the final reflection surface 8b, the finder mirror 1 in FIG.
The observation image becomes darker than the structure provided with the four.

Also in the second embodiment, the image pickup device 1
In 1, only a part of the image on the focusing screen 4 is enlarged and displayed as in the first embodiment, and the operations of the imaging device 11 and the monitor device 12 are the same as those in the flowchart described in FIG. 4. .

[Third Embodiment] In the first and second embodiments, the image pickup apparatus 11 picks up only a part of the observation image light beam by the finder optical system, that is, the periphery of the split image part 4a. However, in the third embodiment, the imaging device 11 captures all of the observation image light flux and displays only a desired portion at a desired magnification when displaying it on the monitor device 12. Is what you do. However,
Since the imaging device 11 once captures the entire luminous flux of the observation image and then enlarges a specific part, there is a disadvantage that the resolution is reduced.

[Fourth Embodiment] In a fourth embodiment, a micro prism is used as the focus adjustment assisting optical member instead of the split image 4a in the first embodiment. is there. A microprism is a collection of fine regular pyramids or hexagonal pyramids and refracts light by the wedge action to separate images. While a split image is two images, a microprism is four or six directions. The image is separated. When it is out of focus, a jagged blurred image is visible, but when it is focused, a smooth image is seen.

[0040]

As described above, according to the present invention, it is possible to provide a single-lens reflex camera capable of easily and strictly adjusting the focus when strict focus adjustment is required, such as during macro photography.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a single-lens reflex camera according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of the imaging device in FIG.

FIG. 3 is an explanatory diagram illustrating an operation in the embodiment of FIG. 1;

FIG. 4 is a flowchart illustrating the operation of the imaging device and the monitor device in FIG. 1;

FIG. 5 is a diagram illustrating a main configuration of a single-lens reflex camera according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing a split image prism.

FIG. 7 is an explanatory diagram for explaining focus adjustment by the split image prism of FIG. 6;

[Description of Signs] 1 ... photographing lens 3 ... movable mirror 4 ... focusing screen 8 ... pentaprism 9 ... eyepiece 10 ... imaging lens 11 ... imaging device 12 ... monitor device 13 ... observer 14 ... finder mirror 15 ... operation member

Claims (3)

[Claims] 1. A single-lens reflex camera comprising: a focusing screen for forming an image of a subject; and a finder optical system for optically observing the subject image on the focusing screen. An imaging unit for imaging a subject image on the focusing screen; and a display unit for displaying the subject image based on a subject image signal captured by the imaging unit. A single-lens reflex camera characterized by displaying only a part of the subject image observed by the finder optical system. 2. A single-lens reflex camera according to claim 1, wherein the range displayed by said display means is around a focus adjustment assisting optical member provided on a focusing screen. 3. A single-lens reflex camera comprising: a focusing screen provided with a focus adjustment assisting optical member at a central portion; and a finder optical system for optically observing a subject image formed on the focusing screen. An imaging unit that captures a subject image on the focusing screen; and a display that displays a partial range on the focusing screen including the focus adjustment assisting optical member based on data captured by the imaging unit. And a means.