JPH04220636A - Pseudo focal distance camera - Google Patents

Abstract

PURPOSE:To enlarge the switching ratio of focal distances without enlarging photographic optical system by presetting a plurality of different pseudo focal distances, and allowing the optical systems to be switched to a plurality of different focal distances. CONSTITUTION:Optical systems 1, 2 for taking photographs which can be switched to a plurality of different focal distances are provided and a combination of the shortest focal distance and the shortest pseudo focal point of the pseudo focal distance of the optical systems 1, 2 and a combination of the longest focal distance and the longest pseudo focal distance are preset. Actual focal distances of the optical systems 1, 2 are preset variously and then a picture is taken and also pseudo focal distances corresponding to respective focal distances are preset. Photographic images can thus be obtained at magnifications corresponding to actual focal distances and trimmed at magnifications corresponding to the pseudo focal distances.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pseudo-focal length camera that magnetically records trimming information on a film according to the angle of view selected and set at the time of photographing.

0002

[Prior Art/Problems to be Solved by the Invention] Recently, multi-focal switching cameras have been commercially available that are so-called compact cameras and are equipped with a focal length switching function so that telephoto shooting or wide-angle shooting can be performed by changing the position of the photographing lens. . In such cameras, in order to increase the switching ratio between the focal length for telephoto shooting and that for wide-angle shooting (long focal length ÷ short focal length), the amount of movement of the photographic lens must be increased. As a result, the camera becomes larger.

[0003] On the other hand, a pseudo focal point can create a pseudo effect as if telephoto shooting or wide-angle shooting was performed using a shooting optical system having a different focal length, even though the shooting is actually carried out using a shooting optical system having a certain focal length. A distance camera has been proposed. This pseudo-focal length camera magnetically records cropping information on the film at the time of shooting so that the photo can be cropped and printed to the same angle of view as if the photo had been taken at a focal length equivalent to telephoto or wide-angle. It is composed of

By the way, if the ratio corresponding to the above-mentioned switching ratio (hereinafter referred to as equivalent ratio) is increased in this pseudo-focal length camera, especially when set to a long focal length, the image will be left as an image and printed due to trimming. There is a disadvantage that the image magnification of the portion becomes extremely high and the roughness of the grains becomes noticeable. Therefore, this equivalent ratio cannot be set extremely large either. The present invention was devised in view of such technical problems in pseudo focal length cameras and to effectively solve them. Therefore, an object of the present invention is to provide a pseudo focal length camera that can set the above-mentioned equivalent ratio as large as possible in the pseudo focal length camera and can be made smaller than a multifocal switching camera having a switching ratio equivalent to such equivalent ratio. It's about doing.

[0005]

[Means for Solving the Problems] A pseudo focal length camera according to the present invention solves the problems of the prior art as described above, and has the following configuration to achieve the object. That is, the pseudo focal length camera of the present invention is a pseudo focal length camera that can set a plurality of different pseudo focal lengths, includes a photographing optical system that can be switched to a plurality of different focal lengths, and has a shortest focal length of the photographing optical system. A combination of the pseudo focal length and the shortest pseudo focal length, and a combination of the longest focal length and the longest pseudo focal length are set.

[0006]

[Operation and Effects of the Invention] In the pseudo focal length camera according to the present invention, the actual focal length of the photographing optical system is set variously to take pictures, and the pseudo focal length is further set according to each focal length. Ru. The resulting photograph is imaged at a magnification that corresponds to the actual focal length, and is further cropped at a magnification that corresponds to the pseudo focal length.

In addition to the switching ratio obtained by switching the actual focal length, the equivalent ratio due to the pseudo focal length has a synergistic effect, so even if the photographic optical system of the camera is compact, it can be used as a camera with a large switching ratio. Equivalent photography can be done.

[0008]

Embodiment A camera according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 6. The camera of this embodiment includes a front group lens 1 and a rear group lens 2 as a photographing optical system, as shown in FIGS. 1 and 2. The front lens group 1 is located on the objective side and is fixed to the lens barrel 3, and a shutter block 1a is provided in front of it. The rear group lens 2 is held by its holding member 2a, and the holding member 2a is mounted within the lens barrel 3 so as to be slidable along its guide shaft 6 in the optical axis direction. The state shown in FIG. 1 is a telephoto shooting state, that is, a telephoto state, and the state shown in FIG. 2 is a wide-angle shooting state, that is, a wide state. In this example, the telephoto state is F number 9.5 and the focal length is 33 m.
This corresponds to a lens with an F number of 5.6 and a focal length of 19 mm in the wide state.

The lens barrel 3 has a cover lens barrel 4 surrounding its outer periphery.
The cover lens barrel 4 is also telescopically held by a lens barrel holding member 5 inside the camera body 40. Therefore, in the telephoto state, both the lens barrel 3 and the cover barrel 4 are extended forward as shown in FIG. 1, and in the wide state, as shown in FIG.
They are retracted to be housed within the camera body 40.

The extending and retracting operations of the lens barrel 3 and the cover barrel 4 are performed by manually operating a switching member 30 provided at the upper end of the camera body 40, as shown in FIG. The switching operation member 30 is
It is provided with an operating pin 30a extending vertically downward from its lower end, and the lower end of the operating pin 30a further engages with an operating communication slit 15b of the lens barrel operating communication member 15 shown in FIG. Manual operation of the switching member 30 is performed by sliding it in the front-rear direction of the camera, and the operation pin 30a also moves in the front-rear direction together with the switching member 30. When the operation pin 30a moves in the front-back direction, the lens barrel operation communication member 15 swings around its rotation axis 15d. The lens barrel operation communication member 15 has a long hole slit 1 on its tip side.
5c, and a connecting pin 3a protruding upward from the upper end of the lens barrel 3 is engaged with this slit 15c. That is, the rocking of the lens barrel operation communication member 15 causes the lens barrel 3 to extend and retract through the slit 15c and the communication pin 3a.

Switching the photographing optical system between the telephoto state and the wide-angle state involves not only extending and retracting the lens barrels 3 and 4, but also changing the distance between the front group lens 1 and the rear group lens 2. The distance changing mechanism is shown in FIGS. 3 and 5. At the lower end of the lens barrel 3, there is a roughly V-shaped interlocking member 21 that interlocks the rear group lens 2 with its extending and retracting operations.
It is attached via its rotation shaft 21c. A long hole slit 21b is formed at one end of the rotation shaft 21c, and an interlocking pin 2b protruding downward from the rear group holding member 2a holding the rear group lens 2 is engaged with this slit 21b. There is. Therefore, the interlocking member 21 rotates in conjunction with the movement of the lens barrel 3, and this movement causes the rear group lens 2 to move in the optical axis direction via the slit 21b, the interlocking pin 2b, and the rear group holding member 2a. . The rotation of the interlocking member 21 is controlled by a pin 21a formed to protrude downward at the end opposite to the end where the slit 21b is formed, and a long cam groove 22a fixed to the camera body 40. The position of the rear group lens 2 is determined by the engagement with the fixed interlocking cam member 22 that has been regulated.

The camera of this embodiment can perform photography by setting two pseudo focal lengths, and has a finder optical system that switches and displays images corresponding to each of the pseudo focal lengths set.
A finder block 20 as shown in FIG. 6 is provided. The finder block 20 has a wide eyepiece surface 20 selected during wide-angle photography, each consisting of a pair of concave and convex surfaces, with both surfaces facing each other in each pair.
a and a wide objective lens surface 20b, and a telescopic eyepiece surface 20c and a telescopic objective lens surface 20d that are selected during telephoto shooting. The optical axes of each pair of lens surfaces are perpendicular to each other, and the finder optical system is switched by rotating 90 degrees at the intersection point. The image obtained by this finder block 20 is an image within a field of view corresponding to an image magnification of 2x (corresponding to telephotography) and 1.4x (corresponding to wide-angle photography) by pseudo focal length photography.

Note that trimming information corresponding to the set pseudo focal length is recorded on the magnetic track 26a of the film by the information writing magnetic head 25. Switching of the trimming information is performed by a signal changeover switch 45 shown in FIG. The signal changeover switch 45 is turned on and off by the operation of the operation pin 30a of the switching operation member 30. When the operation pin 30a moves forward to set the photographic optical system to the telephoto state, the switch 45 is turned on, and the switch 45 is turned on to change to the wide-angle state. If you move backwards to turn it off, it will turn off.

A finder switching cam member 31 is fixed to the lower end surface of the finder block 20. This cam member 31 has an elongated slit 31a formed therein. On the other hand, in the lens barrel operation communication member 15, there is a
A finder contact pin 15a is provided that projects upward and causes the finder optical system to perform its switching operation. The finder contact pin 15a engages with the slit 31a,
The cam member 31 and the finder block 20 move within the slit 31a as the lens barrel operation communication member 15 swings.
and rotate it 90 degrees.

In the camera of this embodiment, the operation of each member is set so that both the photographing optical system and the finder optical system are in the wide-angle state or the telephoto state. therefore,
During wide-angle shooting, in addition to taking pictures using a photographic optical system with a focal length of 19 mm, cropping is performed by 1.4 times when printing, so the resulting photo has a focal length of 27 mm.
mm (≒19 x 1.4), F-number 5.6 lens. In addition, when taking telephoto shots, in addition to taking pictures using a photographic optical system with a focal length of 33 mm, cropping is performed twice when printing, so the final photograph has a focal length of 66 mm (
≒33 x 2) and an F-number of 9.5. In this way, according to the camera of this embodiment, even if the switching ratio is 1.7 times (≒33 ÷ 19) in the actual photographic optical system, it is 2.4 times (≒ 66 ÷ 27) in the finished photograph. A ratio corresponding to the switching ratio of is obtained.

Furthermore, in the pseudo focal length photography by the camera of this embodiment, only 1.4x equivalent photography and 2x equivalent photography are performed, so the image frame of the film is It can be formed by removing the portion that will become the trimming area. Therefore, a size of 25.7 mm x 14.1 mm is sufficient for the image frame, which is advantageous for downsizing the camera body 40a.

In the above embodiment, a bifocal switching lens is used to make the finder optical system compact, but if both the finder optical system and the photographing optical system are configured with zoom lenses, any focal length can be set. You can take pictures by combining this with a pseudo focal length. Furthermore, in the above-described embodiment, the photographing optical system is also capable of zooming, and it is also possible to take photographs with a combination of any focal length between 19 mm and 33 mm and two types of pseudo focal lengths. Further, the focal length set in the photographing optical system is not limited to 19 mm and 33 mm, but can be set arbitrarily, and the pseudo focal length is not limited to 1.4 times and 2 times equivalent.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a photographing optical system of a camera according to an embodiment of the present invention in a telephoto state.

FIG. 2 is a diagram showing the photographing optical system in a wide state in the embodiment of FIG. 1;

FIG. 3 is a diagram showing the schematic configuration of the camera in the embodiment of FIG. 1, seen from the front.

4 is a diagram showing a schematic configuration of a switching mechanism of a photographing optical system in the embodiment of FIG. 1. FIG.

5 is a diagram showing an interlocking mechanism of the rear group lens in the photographing optical system in the embodiment of FIG. 1. FIG.

6 is a diagram showing a finder optical system and its switching mechanism in the embodiment of FIG. 1. FIG.

[Explanation of symbols]

1 Front group lens 2 as part of the photographic optical system Rear group lens 25 as part of the photographic optical system Magnetic head 26a for writing pseudo focal length information Magnetic track 30 for writing pseudo focal length information Switching operation member

Claims (1)

[Claims] 1. A pseudo focal length camera that can set a plurality of different pseudo focal lengths, comprising a photographing optical system (1, 2) that can be switched to a plurality of different focal lengths, the shortest focal length of the photographing optical system and the A pseudo focal length camera characterized in that a combination of a pseudo focal length and a shortest pseudo focal length, and a combination of a maximum focal length and a longest pseudo focal length are set.