JP2010028328A - Camera system and adapter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera system and an adapter capable of photographing at an angle of field closer to an original angle of field when a camera with different image circle is used. <P>SOLUTION: In the adapter 50 to the one attachment/detachment part of which a camera body 30 corresponding to a first camera system is attached, and to the other attachment/detachment part of which an interchangeable lens 20 having an image circle different from that of the first camera system and corresponding to a second camera system is attached, a wide conversion optical system 51 is arranged in a photography optical path between the camera 30 and the interchangeable lens 20 in the adapter 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera system and an adapter, and more particularly to a camera system and an adapter that can be used between camera systems having different image circles.

  In recent years, digital cameras are generally used as photographing devices. Conventionally, a film camera is generally used, and an adapter is commercially available so that the interchangeable lens for the film camera can be attached to a digital camera.

For example, Patent Literature 1 discloses an adapter for mounting on a camera body having an effective screen smaller than the original effective size. This adapter is for attaching an interchangeable lens of a 35 mm silver salt camera to the digital video camera body. By inserting the adapter, a color separation prism is provided between the lens and the CCD as the image sensor. A long back focus for insertion can be secured.
Japanese Patent Laid-Open No. 11-142732

  As described above, there has been proposed an adapter that can use an interchangeable lens even between camera systems having different image circles. However, when such an adapter is attached, only a part of the shooting angle of view of the interchangeable lens can be used. That is, since it is used by being mounted on the camera body of an image circle smaller than the original image circle, shooting is performed with a field angle narrower than the original field angle, in other words, a telephoto field angle.

  For this reason, it is possible to achieve a more telephoto effect during telephoto shooting, but it is often impossible to perform desired shooting with wide-angle shooting. Even a user who uses a telephoto lens, a standard lens, and a wide-angle lens may not function as a wide-angle lens when these lenses are attached to a small image circle camera via an adapter.

  The present invention has been made in view of such circumstances, and provides a camera system and an adapter that enable shooting at an angle of view closer to the original angle of view when using cameras with different image circles. For the purpose.

  In order to achieve the above object, a camera system according to a first aspect of the present invention is an image circle that can attach a camera corresponding to the first camera system to one of the detachable portions and is different from the image circle of the first camera system. In the camera system having an adapter capable of attaching an interchangeable lens corresponding to the second camera system to the other detachable portion, the adapter arranges a wide conversion optical system in a photographing optical path between the camera and the interchangeable lens.

  In the camera system according to the second invention, in the first invention, the image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system have a relationship of Φd1 <Φd2.

  An adapter according to a third aspect of the present invention is a second camera system in which a camera corresponding to the first camera system can be attached to one of the detachable portions and has an image circle different from the image circle of the first camera system. In an adapter capable of attaching a corresponding interchangeable lens to the other detachable portion, the adapter arranges a wide conversion optical system in a photographing optical path between the camera and the lens.

  In the adapter according to the fourth invention, in the third invention, the image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system have a relationship of Φd1 <Φd2.

  An adapter according to a fifth aspect of the present invention is a second camera system in which a camera corresponding to the first camera system can be attached to one of the detachable portions and has an image circle different from the image circle of the first camera system. In an adapter capable of attaching a corresponding interchangeable lens to the other detachable part, the adapter arranges a conversion optical system for reducing the size of the image circle in a photographing optical path between the camera and the interchangeable lens.

In the adapter according to the sixth invention, in the fifth invention, the image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system have a relationship of Φd1 <Φd2.
The adapter according to a seventh aspect of the present invention is that, in the fifth aspect, when the image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system are used, the magnification of the conversion optical system is Φd1 / Φd2.

  ADVANTAGE OF THE INVENTION According to this invention, when using a camera from which an image circle differs, the camera system and adapter which enable imaging | photography with an angle of view nearer to an original angle of view can be provided.

  Hereinafter, a preferred embodiment using a digital camera to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a block diagram showing the internal structure of an internal mechanism of a digital camera according to an embodiment of the present invention along the optical axis direction of the interchangeable lens. FIG. 2 is an external perspective view of the digital camera as viewed from the front side. FIG.

  The digital camera is composed of an interchangeable lens 10 and a camera body 30. The interchangeable lens 10 and the camera body 30 are compatible with the first camera system. A photographing optical system 11 is arranged in the interchangeable lens 10, and a subject image is formed by the photographing optical system 11. The image circle of the photographing optical system 11 is Φd1.

  In the camera body 30, a focal plane shutter 31, an image sensor 32, a liquid crystal monitor 33, a finder 34, and the like are arranged. The focal plane shutter 31 is disposed on the optical axis of the photographing optical system 11 and allows the subject light flux to pass through for a predetermined exposure time.

  An imaging element 32 is disposed behind the focal plane shutter 31 and in the vicinity of the imaging plane of the subject image on the optical axis of the photographing optical system 11. The image sensor 32 photoelectrically converts the subject image formed by the photographing optical system 11 and outputs an image signal. As the image pickup device 32, a two-dimensional image pickup device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) can be used. The size of the image sensor 32 is determined in consideration of the image circle Φd1 of the photographing optical system 11.

  A liquid crystal monitor 33 is disposed behind the image sensor 32. The liquid crystal monitor 33 performs various displays such as live view display, reproduction display of recorded image data, and various menu modes. The liquid crystal monitor 33 is arranged so that the display surface is exposed on the back surface of the camera body 30. However, the liquid crystal monitor 33 is not limited to the back surface as long as it can be observed by the photographer. The display device may be used. Furthermore, it is not limited to a fixed type, and may be a movable type monitor.

  A finder 34 is disposed in the upper part inside the camera body 30. The viewfinder 34 is an electronic viewfinder (EVF), and includes a small liquid crystal monitor that displays a subject image based on an image signal acquired by the image sensor 32, an eyepiece optical system for observing the liquid crystal monitor, and the like. It is configured. The subject image can be observed with either the finder 34 or the liquid crystal monitor 33.

  A release button 35 is disposed on the upper surface of the camera body 30 as shown in FIG. A shooting preparation operation such as focusing and photometry is performed by half-pressing the release button 35, and a shooting operation such as exposure is performed by fully pressing the release button 35.

  Next, a case where the interchangeable lens 20 compatible with the second camera system is attached to the camera body 30 compatible with the first camera system will be described. FIG. 3 is a block diagram of an internal configuration along the optical axis direction of the photographing optical system 21 in a state where the interchangeable lens 20 is attached to the camera body 30 via the adapter 40 for mount conversion.

  In the interchangeable lens 20, a photographing optical system 21 suitable for a second camera system different from the first camera system is disposed. The flange back of the photographing optical system 21 is longer than the flange back of the photographing optical system 11, and the image circle is designed with Φd2 (that is, Φd1 <Φd2) larger than Φd1. For this reason, the image sensor 32 cannot capture the entire subject image formed by the image circle Φd2.

  One side of the adapter 40 is provided with an attachment / detachment portion for attaching / detaching to / from the attachment surface of the interchangeable lens 20, while the other side of the adapter 40 is provided with an attachment / detachment portion for attaching / detaching to / from the attachment surface of the camera body 30. ing. In addition, an optical system is not arranged inside the adapter 40, and the subject light flux from the photographing optical system 21 is directly passed to the camera body 30 side. The adapter 40 may be provided with a communication line for performing communication between the camera body 30 and the interchangeable lens 20 and a communication terminal therefor.

  Next, the case where the adapter 50 incorporating the wide conversion optical system according to the embodiment of the present invention is attached to the camera body 30 will be described. FIG. 4 is an internal configuration block diagram along the optical axis direction of the photographing optical system 21 in a state in which the interchangeable lens 20 is attached to the camera body 30 via the adapter 50.

  The imaging optical system 21 of the interchangeable lens 20 in FIG. 4 is the same as that shown in FIG. 3, and the image circle is Φd2. The camera body 30 is the same as that shown in FIG. One side of the adapter 50 is provided with a detachable part for attaching to and detaching from the mounting surface of the interchangeable lens 20, and the other side of the adapter 50 is provided with a detaching part for attaching and detaching to the mounting surface of the camera body 30. ing. Note that the adapter 50 may be provided with a communication line for performing communication between the camera body 30 and the interchangeable lens 20 and a communication terminal therefor.

In addition, a wide conversion optical system 51 is provided in the optical path of the photographing optical system 21 inside the adapter 50. The magnification of this wide conversion optical system 51 is
Magnification = Φd1 / Φd2
It is.

  Display of a subject image on the liquid crystal monitor 33 or the finder 34 when the magnification of the wide conversion optical system 51 is Φd1 / Φd2 will be described with reference to FIG. FIG. 5A shows a display on the liquid crystal monitor 33 or the like when the interchangeable lens 20 of the image circle Φd2 is attached to a camera body (not shown) suitable for the second camera system using the interchangeable lens 20. .

  FIG. 5B shows the display on the liquid crystal monitor 33 or the like when the interchangeable lens 20 of the image circle Φd2 as shown in FIG. 3 is attached to the camera body 30 suitable for the first camera system via the adapter 40. Show. FIG. 5C shows a display on the liquid crystal monitor 33 or the like when the interchangeable lens 20 of the image circle Φd2 as shown in FIG. 4 is attached to the camera body 30 via the adapter 50.

  FIG. 5A shows an original angle of view of a lens having a large image circle Φd2, and when this subject is attached to the camera body 30 via the mount conversion adapter 40, a part of the image circle Φd2 is shown. Since only the image is taken, as shown in FIG. 5B, an enlarged image is obtained as if the image was taken with a telephoto lens.

  On the other hand, when the interchangeable lens 20 is attached to the camera body 30 via the adapter 50 built in the wide conversion optical system 51, a subject image is generated by the wide conversion optical system 51 at an angle of view similar to that shown in FIG. . That is, since the magnification of the wide conversion optical system 51 is Φd1 / Φd2, the image circle is substantially Φd1, and therefore, a subject image having substantially the same angle of view as that used in the original system of the interchangeable lens 20 is formed. be able to.

  In the description of the present embodiment, the magnification B of the conversion optical system 51 is Φd1 / Φd2, but it may not be exactly the same as above, and may be approximately the same (B≈Φd1 / Φd2). For example, B = 2 × Φd1 / Φd2. In this case, the angle of view is not the same, but it is closer to the original angle of view, so that the uncomfortable feeling can be eased.

  In the present embodiment, the built-in optical system of the adapter 50 is determined so that the image circle satisfies Φd1 <Φd2. However, the present invention is not limited to this, and the focal length may be determined to be a short focal length. . That is, the combined focal length of the built-in optical system of the interchangeable lens 20 and the adapter 50 may be a short focal length based on the focal length of the interchangeable lens 20.

  As described above, in the present embodiment, the adapter 50 has the wide conversion optical system disposed in the photographing optical path between the camera and the interchangeable lens. For this reason, it is possible to shoot at an angle of view closer to the original angle of view.

  In the embodiment of the present invention, a digital camera is used as an apparatus for photographing. However, the camera may be a digital single-lens reflex camera or a compact digital camera, such as a video camera or a movie camera. It may be a camera for moving images, or may be a camera built in a mobile phone or a personal digital assistant (PDA). In any case, the present invention can be applied to any apparatus for photographing that employs a different optical system.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete some components of all the components shown by embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

FIG. 3 is a block diagram of an internal configuration along the optical axis direction of the photographing lens with respect to the internal mechanism of the digital camera according to the embodiment of the present invention. It is the external appearance perspective view seen from the front side of the digital camera which concerns on one Embodiment of this invention. In the digital camera concerning one embodiment of the present invention, it is an internal configuration block diagram along the optical axis direction of photographing optical system 21 in the state where exchange lens 20 was attached to camera body 30 via adapter 40 for mount conversion. is there. In the digital camera according to the embodiment of the present invention, the internal configuration along the optical axis direction of the photographing optical system 21 in a state where the interchangeable lens 20 is attached to the camera body 30 via the adapter 50 of the wide conversion optical system built-in 51. It is a block diagram. 2A and 2B are diagrams illustrating how a subject image is seen in a digital camera according to an embodiment of the present invention, in which FIG. 3A is a subject image at an original angle of view of the interchangeable lens 20, and FIG. (C) shows a subject image when the adapter 50 with the built-in wide conversion optical system 51 is attached.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Interchangeable lens, 11 ... Imaging optical system, 20 ... Interchangeable lens, 21 ... Imaging optical system, 30 ... Camera body, 31 ... Focal plane shutter, 32 ... Imaging Element 33 ... Liquid crystal monitor 34 ... Viewfinder 35 ... Release button 40 ... Adapter 50 ... Adapter 51 ... Wide conversion optical system

Claims (7)

A camera compatible with the first camera system can be attached to one of the detachable parts, and an interchangeable lens compatible with the second camera system having an image circle different from the image circle of the first camera system is attached to the other detachable part In a camera system having an adapter that can be attached to
The adapter system includes a wide conversion optical system disposed in a photographing optical path between the camera and the interchangeable lens. The image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system are
Φd1 <Φd2
The camera system according to claim 1, wherein: A camera compatible with the first camera system can be attached to one of the detachable parts, and an interchangeable lens corresponding to the second camera system having an image circle different from the image circle of the first camera system is attached to the other detachable part In the adapter that can be attached to
The adapter is characterized in that a wide conversion optical system is disposed in a photographing optical path between a camera and a lens. The image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system are
Φd1 <Φd2
The adapter according to claim 3, wherein: A camera compatible with the first camera system can be attached to one of the detachable parts, and an interchangeable lens corresponding to the second camera system having an image circle different from the image circle of the first camera system is attached to the other detachable part In the adapter that can be attached to
The adapter is characterized in that a conversion optical system for reducing the size of the image circle is arranged in a photographing optical path between the camera and the interchangeable lens. The image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system are
Φd1 <Φd2
The adapter according to claim 5, wherein: When the image circle Φd1 of the first camera system and the image circle Φd2 of the second camera system are given, the magnification of the conversion optical system is
Φd1 / Φd2
The adapter according to claim 5, wherein