JP2004012741A - Lens exchange-type camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a photographing range, namely, an angle of view differs by a format even if a lens of a same focal distance is used when the photographing format is freely set. <P>SOLUTION: A lens exchange-type camera system includes a photographing lens 1 and a camera 2, which correspond to different image pickup format sizes and in which mount shapes of the photographing lens and the camera are common. The system is provided with an electric display means 5, a lens side storage means 3 storing information peculiar to the photographing lens including the focal distance of the photographing lens and maximum format information that can be photographed, a camera side storage means 9 storing information peculiar to the camera, which includes the image pickup format size and a display information generation means 4 operating or selecting display information from information peculiar to the photographing lens and the camera and displaying it on the electric display means. The display information generation means generates display information from peculiar information at the time of joining the camera and the photographing lens so as to display it on the electric display means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an interchangeable lens camera system in which a plurality of formats of films or image sensors are mixed.
[0002]
[Prior art]
In a camera system equipped with an interchangeable lens using a conventional silver halide film, the film size is an important factor that determines the image quality and the shooting angle of view, which is the shooting range, in the same system. It was common to use
[0003]
In recent years, with the advent of high-performance electric imaging devices such as CCDs and CMOS sensors that have realized millions of pixels, the flow of computerization is accelerating in fields such as single-lens reflex cameras characterized by high image quality.
[0004]
In an electrical imaging device, the number of pixels is an important factor that determines image quality, and there are various sizes of the imaging device, which is one of the factors that determine the imaging range, that is, the angle of view. This has the advantage of reducing the cost of the entire imaging device by reducing the size of the imaging device even if the number of pixels is the same, or increasing the size of one pixel to obtain sensitivity. As a result, the size of the image sensor increases as a result, and various formats exist depending on applications.
[0005]
[Problems to be solved by the invention]
When such an image sensor is used in an interchangeable lens type camera system, if the format is fixed like a conventional film, the same cost will be incurred for the image sensor from beginner level cameras to those for professional use, and various needs of users And it is necessary to construct a plurality of interchangeable lens systems for each format.
[0006]
In addition, the system will be changed every time the format size is changed due to the progress of technology, and the system that evolves for a long time will be denied.
[0007]
On the other hand, if the format is freely set, even if a lens having the same focal length is used, the shooting range, that is, the angle of view is different depending on the format of the image sensor, or it can be applied to all image sensor sizes as a replacement shooting lens. If this is the case, it is necessary to assume a photographing with the maximum size of the image pickup device and secure a photographable image size corresponding to the photographing. This causes a cost increase of the entire system.
[0008]
[Means for Solving the Problems]
According to the present invention, in a lens interchangeable camera system including a photographing lens and a camera corresponding to different image pickup format sizes, and the photographing lens and the camera have mutually common mount shapes, an electric display means and a focus of the photographing lens are provided. Lens-side storage means for storing information specific to a photographic lens including distance and maximum format information that can be photographed, camera-side storage means for storing camera-specific information including an imaging format size, and information specific to a photographic lens and a camera Display information generating means for calculating or selecting display information from the electronic display means, and displaying the information on the electric display means. On the target display means.
[0009]
Thus, even in an interchangeable lens camera system in which a plurality of imaging formats (sizes) are mixed, appropriate information regarding the angle of view is displayed so that the photographer is not confused, and use of the camera and the lens is restricted by a combination of the camera and the lens. For example, can be displayed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration of a camera system of an interchangeable lens type according to an embodiment of the present invention.
[0011]
Reference numeral 1 denotes a photographing lens, and an optical lens which is a basic function as the photographing lens is not shown.
[0012]
Reference numeral 2 denotes a camera, and basic elements relating to photographing as the camera are not shown.
[0013]
First, the configuration of the taking lens 1 will be described. Reference numeral 3 denotes a memory which is built in the photographing lens 1 and stores optical information on the photographing lens 1. The memory 3 includes focal length information as optical information, exit pupil position information, vignetting information on peripheral light amount change, Fno information, It provides necessary data to the arithmetic unit 4 including distortion information and the like.
[0014]
The arithmetic unit 4 receives the optical information of the photographing lens 1 and the information on the image sensor (not shown) stored in the memory 9 provided in the camera 2 and displays the information on the display device 5 which is an electric display means. (Display information) is calculated.
[0015]
The display device 5 includes a liquid crystal display device for displaying the display information calculated by the calculation device 4, an LED segment, and the like.
[0016]
The display memory 6 stores the display information calculated by the calculation device 4, and stores and holds the display information even after the taking lens 1 is detached from the camera 2.
[0017]
Reference numeral 7 denotes a contact provided on the lens side for transmitting information, which may be an electrical connection portion, an information communication form using an optical connector, or an information transmission means such as wireless communication. In addition, a plurality of methods may be provided.
[0018]
In the case of adopting a wireless communication form, since the camera and the lens can exchange information without joining the physical mount, it is possible to provide photographing angle information to a photographer described later more quickly. It can be carried out.
[0019]
Next, the configuration of the camera 2 will be described. Reference numeral 8 denotes a contact provided on the camera side for transmitting information. Like the contact 7, an electrical connection unit, an information communication form using an optical connector or the like, or information such as wireless communication is used. Transmission means may be used. However, it is necessary to provide at least one of the same systems as the photographing lens 1.
[0020]
The memory 9 is information on an image sensor (hereinafter, referred to as image sensor information), and stores information on an imaging screen size determined by the size of the image sensor, information on a set entrance pupil position by a microlens provided on the front surface of the element, and the like. Have been.
[0021]
In the present embodiment, the image sensor information stored in the memory 9 on the camera side is sent to the arithmetic unit 4 built in the photographic lens 1 via the contacts 8 and 7. The computing device 4 computes display information based on the transmitted image sensor information and the optical information stored in the memory 3 and causes the display device 5 to display the information.
[0022]
As another embodiment, as shown in FIG. 2, an arithmetic unit 4 ′ is built in the camera 2, and optical information of the photographing lens 1 is transmitted via the contacts 7 and 8 to the arithmetic unit 4 ′ on the camera 2 side. May be transmitted. In this case, the arithmetic unit 4 ′ calculates display information based on the image sensor information stored in the memory 9 and the optical information of the photographing lens 1 sent from the lens side, and outputs the calculated display information to the contact 8. , 7 are displayed on the display device 5 on the lens side.
[0023]
As still another embodiment, as shown in FIG. 3, an arithmetic unit 4 ′ and a display unit 5 ′ are built in the camera 2, and optical information of the photographing lens 1 is transmitted to the camera via contacts 7 and 8. The information may be transmitted to the arithmetic device 4 'on the second side. In this case, the computing device 4 ′ computes display information based on the imaging device information stored in the memory 9 and the optical information of the photographing lens 1 sent from the lens side, and displays the computed display information on the display device. Display at 5 '. When the display device 5 'is provided on the camera side in this way, a dedicated display device for displaying the display information may be provided, or when there is a viewfinder display device used for an electronic viewfinder. It is also possible to display the calculated display information together with the image information of the subject on the finder display device.
[0024]
Here, a case where the display angle information as display information is displayed on the display device 5 will be described. Assuming that the focal length of the photographing lens 1 attached to the camera 2 is f, the diagonal dimension of the image sensor provided in the camera 2 is H, and the photographing angle of view on the diagonal is one side (half angle of view) ω,
ω = atan (H / 2f) (1)
It becomes.
[0025]
That is, the arithmetic unit 4 reads the focal length f and the diagonal dimension H from the memory 3 in the photographing lens 1 and the memory 9 on the camera 2 side, respectively, and calculates ω using the above equation (1). , Ω or 2ω is displayed on the display device 5. As a result, information on the angle of view can be appropriately notified to the photographer.
[0026]
In the conventional interchangeable lens type camera system, since the format of the imaging film is fixed, the photographer senses the shooting angle of view sensuously by the focal length of the lens, and the fixed focal length imprinted on the shooting lens. Also, in the case of the zoom lens, the index is changed due to zooming, and information about the angle of view can be sufficiently transmitted to the photographer only by pointing to the engraved numerical value.
[0027]
On the other hand, in the present embodiment, the case where the angle of view itself is displayed as the angle as the information related to the angle of view has been described, but it is expected that it is difficult for a photographer who is used to the conventional camera system to intuitively grasp the angle of view. . In such a case, it is easy to convert and display the focal length of the angle of view corresponding to the conventional silver halide film format instead of the angle of view information calculated by the equation (1).
[0028]
That is, assuming that the actual focal length of the lens is f, the focal length converted to the conventional format is fo, the diagonal dimension of the image sensor of the camera is H, and the diagonal dimension of the conventional format is Ho,
fo = f × Ho / H (2)
Therefore, this fo may be displayed on the display device 5.
[0029]
The diagonal dimension of the 135 format used for conventional single-lens reflex cameras and the like is 43.2 mm. If this is calculated and displayed as Ho, the photographer can infer the angle of view from the focal length with the same feeling as before. it can. This is very important for photographers accustomed to conventional formats.
[0030]
Until now, a case has been described where the image size that can be photographed, that is, the format, is determined by the image sensor or the film size. Next, another embodiment will be described.
[0031]
That is, if the image size that can be photographed by the photographing lens 1, that is, the image size is smaller than the photographing size of the image pickup device or the film, and the photographable format is determined by the image size of the photographing lens 1, instead of H in Expression (2), By using the image size diagonal dimension Hf of the taking lens 1,
fo = f × Ho / Hf (3)
Thus, the converted focal length to the conventional format can be calculated.
[0032]
In a zoom lens, a focal length changes due to zooming. However, a position sensor or the like for detecting a zoom position is provided in the photographing lens 1 to extract focal length information from the zoom position, and to store image size information in a memory in the camera 2. 9, the display information can be calculated and displayed using the equations (1), (2), and (3).
[0033]
Further, even when an extender for converting the focal length is attached, the conversion focal length and the angle of view can be calculated from the magnification information of the extender.
[0034]
If the position information of the focus lens of the photographing lens 1 is detected and the photographing distance can be detected, the photographing magnification can be calculated together with the focal length information.
[0035]
That is, if the focal length is f and the subject distance is L, the photographing magnification β is
β = f / L (4)
It becomes.
[0036]
Here, if f is the conventional format-converted focal length fo, the conventional format-converted magnification can be calculated. By displaying this, the imaging magnification can be determined.
[0037]
By the way, as a problem unique to the image pickup device, there is a problem of a set entrance pupil position by a microlens installed on the front surface of the device in order to efficiently capture a photographing light beam. Conventionally, in a photographing lens of a video camera, the exit pupil of the photographing lens is set at infinity, a so-called telecentric state, and the entrance pupil position of the micro lens of the image pickup device is set at infinity to achieve matching as an imaging system. I have.
[0038]
However, when the size of the image sensor increases, it is difficult to make the corresponding lens telecentric, or in consideration of sharing the conventional film camera system with the photographing lens, the film photographing lens is located at the exit pupil position. Are various from near to far, and it is difficult to set the microlens entrance pupil position of the image sensor corresponding to all of them.
[0039]
Therefore, in the system of the present embodiment, it is also possible to determine the photographable angle of view from the exit pupil position information of the photographing lens and the entrance pupil position information of the image sensor, and to display the determined image angle on the display device 5.
[0040]
Specifically, when the exit pupil position of the imaging lens is somewhat close to the entrance pupil position determined by the microlens of the imaging device, the imaging field angle or converted focal length is calculated by setting the entire surface of the imaging device as an effective imaging region. If the pupil position is far away, an effective imaging area may be determined according to the degree of the pupil position, and a photographing angle of view or a converted focal length that can be photographed may be calculated and displayed.
[0041]
For example, if the photographable range is obtained by calculation from the relationship of the pupil position, the distance to the exit pupil position of the lens with respect to the imaging plane is Lo, and the distance to the entrance pupil position of the image sensor is Lin. Assuming that the image height of the image sensor is h, the range of h that satisfies the following expression is set as the photographable range, and the angle-of-view information is displayed by the above-described method.
[0042]
0.25 <atan (h / Lo) / atan (h / Lin) <10 (4)
When the value of the equation (4) is 1, it indicates that the exit pupil of the imaging lens 1 and the entrance pupil of the image sensor match. If the upper limit or the lower limit is exceeded, the amount of incident light decreases, which makes the image unsuitable.
[0043]
Note that the display device 5 may be provided on the camera side. However, since it is necessary to display various information on exposure and photographing data on the camera side, displaying information on the angle of view tends to be complicated. Therefore, it is desirable that the display device be provided on the lens side. Until now, information about the shooting angle of view, such as the focal length, has been fixedly displayed on the lens, so that the user does not feel uncomfortable.
[0044]
In addition, the information displayed on the lens is retained by the function of the memory 9 even after the lens 1 is detached from the camera 2, so that the information and focus on the photographing angle of view can be obtained before the lens is mounted again. The photographer can grasp the distance, and can be attached to the camera without confusion.
[0045]
Further, when cameras of a plurality of formats are included, it is also preferable that a plurality of display information be retained and configured to be switched automatically or manually. If a display information switching unit is provided to switch manually or automatically, the focal length or the shooting angle of view is displayed immediately after mounting, and the shooting distance according to the position of the focus lens is displayed at the time of shooting. It is possible to manually or automatically switch between displaying the focal length during zooming and displaying the photographing distance during shooting with a zoom lens.
[0046]
【The invention's effect】
As described above, according to the present invention, even in a lens-interchangeable camera system in which a plurality of imaging formats (sizes) are mixed, appropriate information regarding the angle of view is displayed so that the photographer is not confused, For example, it is possible to display information related to the restriction of use by the combination of the camera and the lens, and it is possible to improve the convenience for the photographer.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an interchangeable lens camera system according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of an interchangeable lens camera system according to another embodiment of the present invention.
FIG. 3 is a configuration diagram of an interchangeable lens camera system that is still another embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 photographing lens 2 camera 3 memories 4 and 4 ′ for storing optical information computing devices 5 and 5 ′ display device 6 memories 7 and 8 for storing display information contacts 9 memories for storing image sensor information

Claims (8)

A lens interchangeable camera system including a photographing lens and a camera corresponding to different imaging format sizes, respectively, wherein the photographing lens and the camera have a common mount shape.
Electrical display means;
Lens-side storage means for storing information specific to the photographing lens including the focal length of the photographing lens and the maximum format information that can be photographed,
Camera-side storage means for storing camera-specific information including an imaging format size,
Display information generating means for calculating or selecting display information from information unique to the taking lens and camera, and displaying the information on the electric display means,
The lens-interchangeable camera system according to claim 1, wherein the display information generating means generates display information from unique information at the time of joining the camera and the photographing lens, and displays the display information on the electric display means. The interchangeable lens camera system according to claim 1, wherein the display information is information on a shooting angle of view. The interchangeable lens camera system according to claim 1, wherein the display information is information on a converted focal length. 2. The interchangeable lens camera system according to claim 1, wherein the display information is information on a restriction including whether or not the mounted photographing lens can be used. The interchangeable lens camera system according to any one of claims 1 to 4, wherein the electric display means is provided on a taking lens. 6. The interchangeable lens camera system according to claim 5, wherein the electrical display unit retains the display of the display information even after the taking lens is removed from the camera. The unique information of the taking lens includes the exit pupil position information of the taking lens. 7. The interchangeable lens camera system according to claim 1, wherein a format size capable of photographing is calculated or selected from the information, and the format size information is displayed on the electric display means. When the distance to the exit pupil position of the photographing lens is Lo, the distance to the entrance pupil position of the image pickup device is Lin, and the image height at the image pickup device is h, based on the image forming surface,
0.25 <atan (h / Lo) / atan (h / Lin) <10
8. The interchangeable lens camera system according to claim 7, wherein a range of h that satisfies is set as a photographable range, and information on the photographable range is displayed on the electric display unit.

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