JPH04320207A - Lens shutter camera - Google Patents

Abstract

PURPOSE:To obtain a lens shutter camera in which the parallax of each system is a little by appropriately arranging an automatic focusing system, a finder system, and a photometric system in a camera main body independently of a photographic lens. CONSTITUTION:The light projecting system 2 for automatic focusing, the light receiving system 3 and the finder system 4 are arranged independently of the photographic lens (1) in the camera main body 101 in such a way that the finder system is positioned closer to side of the light projecting system than the side of the light receiving system, and each system is positioned in the camera main body 101 so as to be nearly on concentric circles with respect to the optical axis of the photographic lens.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a so-called lens shutter camera in which a finder system, an autofocus system (automatic focus detection device), a photometry system, etc. are provided in the camera body independently of the photographic lens, and in particular, the present invention relates to a so-called lens shutter camera in which a finder system, an autofocus system (automatic focus detection device), a photometry system, etc. are provided in the camera body independently of the photographic lens. The present invention relates to a lens shutter camera in which each system is appropriately arranged to reduce optical parallax in each system while reducing the size of the entire camera.

0002

[Prior Art] Lens-shutter cameras have traditionally been widely used as cameras with a simple configuration in which a finder system, autofocus system, photometry system, etc. are provided as part of the camera body independently of the photographic lens. .

FIG. 2 is a typical front schematic view of a conventional lens shutter camera. In the figure, 20 is a camera body, 21 is a photographing lens, and 22 is an autofocus light projection system, which has a light source and a light projection lens. Reference numeral 23 denotes an autofocus light receiving system, which includes a light receiving lens and a light receiving element. 24 is a finder system, and 25 is a photometric system, which includes a photometric lens and a light receiving element. 26 is a strobe light emitting section.

The autofocus system shown in the figure utilizes a so-called active type triangular distance measuring system having a light projecting system 22 and a light receiving system 23.

[0005]

[Problems to be Solved by the Invention] It has become essential for cameras with simple configurations, such as recent lens shutter cameras, to be equipped with an autofocus function. For this reason, autofocus accuracy has come to play a large role in evaluating camera performance.

In general, in an autofocus system using a triangular distance measurement method, in order to improve distance measurement accuracy, it is necessary to make the baseline length, which is the distance between the light projecting system and the light receiving system, as long as possible.

However, if the base line length is increased, the overall size of the camera increases accordingly, so it cannot be made too long. Also, the conventional autofocus system is shown in Figure 2.
As shown in FIG.
In contrast to No. 1, since the camera was placed on one side above the camera body, there was a tendency for distance measurement parallax to occur, where the distance measurement range and the photographing range deviate depending on the object distance.

In addition, since the photometry system 25 is also relatively far away from the photographing lens 21, there is a tendency for photometry parallax, in which the photometry range and the photographing range deviate depending on the object distance, to occur.

[0009] The present invention provides a finder system, an autofocus system, and a distance measurement system in the camera body independently of the photographic lens, and by appropriately arranging these systems, it is possible to miniaturize the entire camera while achieving high precision. To provide a lens shutter camera capable of accurate distance measurement and photometry, and with less distance measurement parallax, photometry parallax, and finder parallax for a photographing lens.

0010

[Means for Solving the Problems] The lens shutter camera of the present invention has a light projecting system, a light receiving system, and a finder system for autofocus independent of the photographing lens. The system is located on the side of the camera body, and each system is arranged in the camera body so as to be located approximately concentrically with respect to the optical axis of the photographic lens.

Particularly, in the present invention, the light projecting system and the light receiving system are arranged at substantially symmetrical positions with respect to the optical axis of the photographing lens, and the photometry system is arranged at a position that is higher than the light receiving system independently of the photographing lens. It is characterized by being located on the camera body so as to be located on the light projecting system side and approximately concentrically with respect to the optical axis of the photographic lens.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of a main part of a lens shutter camera according to a first embodiment of the present invention when viewed from the front.

In the figure, 1 is a photographing lens, and 2 is an autofocus light projecting system, which includes a light projecting lens and a light source. Reference numeral 3 denotes an autofocus light receiving system, which includes a light receiving lens and a light receiving element. The light projecting system 2 and the light receiving system 3 are located at substantially symmetrical positions with respect to the optical axis 1a of the photographic lens 1, and the optical axis 1a
They are placed at approximately equal distances from each other.

4 is a finder system, and a photographing lens 1
It is located above the camera body. 5 is a photometry system.

The finder system 4 and the photometry system 5 are both arranged closer to the light projecting system 2 than the light receiving system 3, that is, closer to the light projecting system 2. 102 is a strobe light emitting section.

In this embodiment, as described above, each system such as the finder system 4, the autofocus system's light emitting system 2 and light receiving system 3, and the photometry system 5 are arranged approximately concentrically with respect to the optical axis 1a of the photographic lens 1. It is located in This allows for the miniaturization of the entire camera while also reducing the parallax of each system (ranging parallax,
(photometering parallax, finder parallax) is reduced overall.

In this embodiment, a substantially concentric circle with respect to the optical axis 1a of the photographic lens 1 is a concentric circle with a length within ±30% of the distance (radius) L from the optical axis 1a to the farthest optical system. A donut-shaped area surrounded by The present embodiment is characterized in that each of the above-mentioned systems is arranged within this doughnut-shaped area.

Next, the structural features of each system of this embodiment will be explained.

FIG. 3 is an explanatory diagram of the optical arrangement of the finder system 4 and the photographic lens 1. In the figure, 31 and 32 indicate objects.

As shown in the figure, if the position of the finder system 4 and the position of the photographic lens 1 are far apart, the finder parallax is corrected at a certain object distance L31, but at other object distances, the viewfinder parallax is corrected. A lot of parallax occurs. Especially when the closest object distance becomes L32, the finder parallax becomes large.

Therefore, in this embodiment, in order to reduce finder parallax, the finder system 4 is located above the camera body and as close to the photographic lens 1 as possible, as shown in FIG. .

FIG. 4 is an explanatory diagram of the optical arrangement of the light projecting system 2 and the light receiving element 3 of the autofocus system.

In the figure, a light beam from a light source 2a of a light projection system is irradiated onto an object 41 by a light projection lens 2b, and the reflected light from the object 41 is imaged by a light receiving lens 3b on the surface of a line sensor 3a. Then, the image position 41 of the reflected light from the object 41 formed on that surface by the line sensor 3a.
By detecting a, the distance L41 to the object 41 is determined.

In an autofocus system using such an active type triangular distance measurement method, distance measurement accuracy can be improved by increasing the baseline length, which is the distance between the light emitting system and the light receiving system. can. However, increasing the baseline length increases the size of the entire camera. On the other hand, if the baseline length is shortened, the entire camera becomes smaller, but the sensitivity of the imaging position of the light beam on the line sensor surface of the light receiving system to changes in the object distance becomes smaller, and the distance measurement accuracy decreases. .

In general, it is preferable that the distance measuring range be located near the center of the photographing range determined by the photographing lens, that is, it is preferable that the distance measuring parallax is small.

Therefore, in this embodiment, as shown in FIG. 1, the light projecting system 2 and the light receiving system 3 are brought as close as possible to the optical axis 1a of the photographing lens 1, and are approximately symmetrical with respect to the optical axis 1a of the photographing lens 1, that is, the light They are arranged so as to be located on concentric circles that are approximately the same distance from the axis 1a. This prevents the overall size of the camera from increasing, increases the baseline length, improves distance measurement accuracy, and minimizes distance measurement parallax.

FIG. 5 is an explanatory diagram of the optical arrangement of the light projecting system 2, light receiving system 3, and finder system 4 of the autofocus system.

As shown in the figure, suppose that the finder system 4 is located closer to the light receiving system 3 than the light projecting system 2, contrary to the present invention. At this time, the light is projected onto the object 51 via the light projection system 2,
A spot image based on the reflected luminous flux is formed in the viewfinder field of view, and as shown in FIG. It changes greatly to point zone 62. As a result, the distance measurement range zone 63 increases.

Therefore, in this embodiment, as shown in FIG. 1, the finder system 4 is located closer to the light emitting system 2 than the light receiving system 3, so that the spot image in the finder field of view 64 is separated from the far point zone 61 to the near point zone. The amount of change to 62 is made to be small.

In addition, in this embodiment, when the photometry system is provided independently from the photographic lens, it is located closer to the light projecting system 2 than the light receiving system 3 and is located relative to the optical axis 1a of the photographic lens 1, as shown in FIG. They are located on approximately concentric circles. This reduces photometry parallax, which is the discrepancy between the shooting range determined by the shooting lens and the photometry range, and also ensures that the range determined by the distance measurement range zone is located approximately at the center of the photometry range, resulting in high precision. This enables accurate photometry.

FIG. 7 is a schematic diagram of a main part of a lens shutter camera according to a second embodiment of the present invention when viewed from the front. In this figure, the same elements as those shown in FIG. 1 are given the same reference numerals.

In this embodiment, as shown in the figure, the light projecting system 2 and light receiving system 3 of the autofocus system are not symmetrical with respect to the optical axis 1a of the photographic lens 1, but are arranged on one side of the photographic lens 1. This embodiment differs from the first embodiment shown in FIG.

That is, the finder system 4, the photometry system 5, and the light projecting system 2 and light receiving system 3 of the autofocus system are each arranged substantially concentrically with respect to the optical axis 1a of the photographing lens. At this time, the finder system 4 and the photometry system 5 are each located closer to the light projecting system 2 than the light receiving system 3 is.

In this embodiment, each system is arranged on one side of the camera body 101 while satisfying the above-mentioned conditions, thereby achieving the above-mentioned effects while simplifying the assembly of each system.

[0035]

According to the present invention, when a finder system, an autofocus system, and a distance measurement system are provided in the camera body independently of the photographic lens, by appropriately arranging these systems as described above, the entire camera can be improved. It is possible to achieve a lens shutter camera that is capable of high-precision distance measurement and photometry while reducing the size of the camera, and has less distance measurement parallax, photometry parallax, and finder parallax for the photographing lens.

[Brief explanation of drawings]

[Fig. 1] Front schematic view of Example 1 of the present invention

[Figure 2]
Front schematic diagram of a conventional lens-shutter camera

[Figure 3]
Explanatory diagram of the optical arrangement of the photographing lens and finder system

[Figure 4] Explanatory diagram of the optical arrangement of the light emitting system and light receiving system of the autofocus system

[Figure 5] Explanatory diagram of the optical arrangement of the light emitting system and light receiving system of the finder system and autofocus system

[Figure 6] Explanatory diagram of the near point zone and far point zone within the viewfinder field of view

[Fig. 7] Front schematic view of Example 2 of the present invention

[Explanation of symbols]

1 Photography lens 2　Light projection system 3 Light receiving system 4 Finder system 5 Photometry system 101 Camera body

Claims (3)

[Claims] Claim 1: A light projection system, a light reception system, and a finder system for autofocus are arranged independently of the photographic lens, and the finder system is located closer to the light projection system than the light reception system, and each system is connected to the photographic lens. A lens shutter camera, characterized in that the lens shutter camera is arranged on a camera body so as to be located substantially concentrically with respect to the optical axis of the camera. 2. The lens shutter camera according to claim 1, wherein the light projecting system and the light receiving system are arranged at substantially symmetrical positions with respect to the optical axis of the photographing lens. 3. A photometric system is mounted on the camera body, independently of the photographic lens, so as to be located closer to the light emitting system than the light receiving system, and approximately concentrically with respect to the optical axis of the photographic lens. 2. The lens shutter camera according to claim 1, wherein: