JPS6049312A - Photographing device - Google Patents

Abstract

PURPOSE:To facilitate focusing even when an optical system has a large F number and the brightness of a subject is low by providing a means which divides a pupil into two in an optical path of photography, and performing the focusing through the divided pupil parts. CONSTITUTION:Luminous flux from the subject 1 is split by two aperture parts 3b and 3c of a moving stop 3, and the image is observed through observation systems 3, 4, 7 and 8; when there are two images seen, the lens 2 is shifted in position so that the image of the subject 1 is seen as one point. When releasing operation is performed during photography after the focusing is completed, the moving stop 3 moves horizontally. Then, a quick-return mirror 4 is hopped up to form the optical path extending to a film 6, and the light from a viewfinder is cut off at the same time. Then, a shutter 5 is opened to expose the film 6 to the image of the subject 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photographic device, and more particularly to a photographic device capable of accurate focusing.

In general, a method for focusing in a photographic device is to bend the optical path for photographing using a mirror or the like, and to place a focusing screen (focusing glass) on a surface of the bent optical path that is conjugate with the photographic film. Conventional focusing screens include a matte surface made of frosted glass, a split prism in which semicircular wedges are combined in opposite directions in the center, a microprism in which many small prisms are formed on one side of the glass, and an aerial image using a crosshair. There is a way to match. however,
The matte surface makes it difficult to get the sharpest point of focus for objects with low brightness, and split prisms and microprisms cannot be used with lenses with large F numbers. Furthermore, the method using crosshairs has the disadvantage that it requires a change of viewpoint in order to focus because it utilizes parallax, and requires some skill.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional example, an object of the present invention is to provide a photographic device that includes means for dividing the pupil into at least two parts in the photographing optical path and performs focusing through the divided pupil. do.

Therefore, according to the present invention, it is possible to easily perform focusing even in an optical system with a large F number or a subject with low brightness.

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram of an embodiment of the present invention, and shows the optical path when an object is focused.

In the figure, there is a diaphragm fixed on the optical axis on the image field side of the length. , a diaphragm 3 movable perpendicularly to the optical axis direction, a quick return mirror movable in the upward direction in the figure by being coupled to a release mechanism (not shown), a focal plane shutter, and a filler frame are arranged. A pentaprism 7 and an eyepiece g are arranged along an optical path bent at right angles to the optical axis by a mirror q. The surface of the film B and the lower surface 7a of the pentaprism 7 are arranged in a conjugate relationship. Here, the length, fixed aperture W, and focal plane shutter constitute the photographing system of this device, and the movable aperture 3, quick return mirror P, and pentaprism 7
, the eyepiece constitutes an observation system.

To explain in detail about the above-mentioned aperture 3.9, the movable aperture 3 is as follows.
As shown in FIG. 2, it has a substantially rectangular shape, with a portion having seven openings 3a and a portion having an elliptical opening 3b, 3a.
It also has a protrusion at one end.

As shown in FIG. 3, the fixed diaphragm 7 has a square shape and has an opening 9a having the same shape as the opening 3a of the movable diaphragm 3.

Note that the opening shapes of the openings 3b and 3c are not limited to ellipses and may be of any shape, but it is necessary that both of them as a whole fall within the range of an opening having the same shape as the opening 3a.

FIGS. 9(A) and 9(B) are front views of the movable diaphragm 3 and its driving mechanism as viewed from the image field side, each showing the state in focus during photographing. The aperture 3 is slidably fitted along the groove /3a of the guide member /3. Although not shown in the figure, the fixed aperture 9 is arranged on the back side of the movable aperture 3, and in the case of FIG. 7(A), the aperture 3a of the movable aperture 3 and the aperture 9a of the fixed aperture are matches. Protrusion of moving aperture 3/
/ is engaged with the elongated hole 10a of the drive lever 10 of the rotary linenoid /2.

In the above configuration, focusing will first be explained. The light flux emitted from the subject is divided by the two apertures 3b and 3c of the movable diaphragm 3, and this image is formed by the observation system 3. %
When observed through Z g, when the beam is out of focus, the a principal rays do not coincide, so two appear. Therefore, in order to focus, it is only necessary to move the length position so that the image of the subject appears at seven points.

Next, the time of shooting will be explained. When the release operation is performed after the above-mentioned focusing is completed, the rotary solenoid /2 is energized and the drive lever 1 is turned on in the state shown in FIG. 7(B).
0 rotates clockwise and the movable diaphragm 3 is moved horizontally along the groove /3a of the guide member /3 by the protrusion // that engages with the elongated hole 10h of the drive lever 10, as shown in Fig. 7(A). becomes the state of Subsequently, the quick return mirror shown in FIG. 1 is flipped up to form an optical path to film B, and at the same time, light from the finder is blocked. Next, the shutter S is opened and the image of the subject is exposed onto the film B. (When the exposure is completed, the shutter 3 is closed and the quick return mirror is returned to the position shown in Figure 1, and the rotary solenoid is moved to the rotary solenoid /2. The current is cut off, and the movable aperture 3 moves as shown in Fig. 7 (B).
Return to state.

In the above embodiment, a diaphragm 3 as shown in FIG. 2 is used as a means for dividing the pupil, but a bar-shaped light shielding member is placed across the center of the opening 9a of the fixed diaphragm 9 to divide the pupil. It goes without saying that the number of pupil divisions is not limited to two, but may be a plurality.

Furthermore, as shown in FIGS. S and 3, the pupil may be divided by combining a polarizing plate/4 and a liquid crystal device/S.

That is, when focusing, a current is passed to the left of the liquid crystal device/S to form λ transparent parts as shown in FIG. 3, and when photographing, the current is stopped and the entire area of the liquid crystal device/S becomes transparent. While the above-mentioned embodiment requires a space for moving the diaphragm 3, the case shown in FIG.

As explained above, by dividing the pupil, it becomes possible to easily perform focusing even on a subject with low brightness or a lens with a large F number.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of one embodiment of the present invention, and FIG. 2 is a diagram of the first embodiment of the present invention.
Figure 3 is a front view of the fixed aperture shown in Figure 1, Figures (A) and (B) are block diagrams of the movable aperture drive device, Figures The figure is a schematic diagram of a pupil division device according to another embodiment of the present invention. 3...Moving aperture 15...Liquid crystal device Fig. 4 (A) Fig. 5 Fig. 4 CB) Fig. 6

Claims (3)

[Claims] (1) A photographic device having a means for dividing the pupil into two parts in the photographing optical path, and focusing via the divided pupil. (2) The photographing apparatus according to claim 1, wherein the photographing apparatus is configured to perform photographing using seven divided pupils. (3) The photographing device according to claim 2, wherein the pupil at the time of focusing and the pupil at the time of photographing are switched by energizing a liquid crystal member.