Abstract:
A still camera viewfinder comprising a reticle lens having more than one frame thereon and which is selectively positionable in the viewing area, and viewing area masking plate arms which are coupled to said reticle lens to open or selectively mask portions of the viewing area dependent upon the film format or lens in use.

Description:
This invention relates to a viewfinder for a still camera which enables a user to change the size and shape of the frame for the viewing area according to the film format or to the lens in use. 
     BACKGROUND OF THE INVENTION 
     There are still cameras with which users can obtain, adding to the standard film format pictures, pictures of other formats such as panoramic and HDTV (High-Density TV) format, and there are cameras which can use interchangeable lenses such as telephoto lenses and wide angle lenses having variable focal length. 
     In such a still camera, whenever the film format is changed or the lens is changed, the viewing area and size of the view finder frame must be changed according to the format or the lens in use to cover the proper viewing and picture taking areas. 
     FIG. 1 shows a typical viewfinder which is comprised of an object lens (1), a mirror lens (2), a reticle (frame line) lens (3) and an eyepiece lens (4). 
     To have more than one size of frame with a viewfinder matching with more than one film format or more than one interchangeable lens, the frames are usually provided on one reticle overlapping each other or placing a smaller frame in a bigger frame. 
     FIG. 2 shows typical frames provided on a reticle lens for three different kinds of film format, which is a frame for the standard 35 mm format (5), a frame for panorama format (6) and a frame for HDTV format (7), showing the viewing area of each format indicated by the frames provided on one reticle lens. 
     FIG. 3 shows the typical frames provided on a reticle lens for three different kinds of lens, which is a frame for standard lens (8), a frame for wide angle lens (9) and a frame for telephoto lens (10), showing the viewing area of each lens indicated by the frames provided on one reticle lens. 
     As shown by FIG. 2 and 3, if more than one frame is provided on a single reticle lens overlapping each other or with a smaller frame put in a bigger frame, users always see all of them simultaneously and may experience confusion, complication and difficulty of frame distinction. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a view finder for a camera capable of taking pictures in more than one film format and for a camera which is capable of using more than one lens wherein the viewfinder displays only one visible frame at a time which matches with the selected format or the lens in use. 
     The viewfinder of the present invention is comprised of an object lens, a mirror lens, a reticle lens which has broader width than ordinary reticle lenses to have enough room for more than one frame to be displayed, and an eyepiece lens. 
     Because of the broader width of the reticle lens, multiple frames can be arranged side by side on the reticle lens without any overlapping and without placing a smaller frame in a bigger frame. 
     By moving the reticle lens from right to left or left to right coupling the selection of the film format or the lens, only one frame is visible at a time in the viewfinder and the visible frame which matches with the selected film format or the lens in use. 
     Thus, although the camera has more than one film format or more than one lens to be used, the user will always see only one frame in the viewfinder without any confusion, complication and difficulty of frame distinction caused by seeing multiple frames in the viewing area at a time. 
     This and other objects, advantages and features of the present invention will be more fully understood and appreciated by reference to the written specification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows typical prior art viewfinder which is comprised of an object lens, a mirror lens, a reticle (frame line) lens and an eyepiece lens; 
     FIG. 2 show the typical prior art frames provided on a reticle lens for three different kinds of film formats, a first comprising a frame for a standard 35 mm format, a second comprising a frame for panoramic format and a third comprising a frame for HDTV format, showing the viewing area of each format indicated by the various frames all provided on the reticle lens; 
     FIG. 3 shows the prior art frames provide on a reticle lens for three different kinds of lenses, the first comprising a frame for standard lens, the second a frame for wide angle lens and the third comprising a frame for telephoto lens, showing the viewing area of each lens indicated by the various frames on the reticle lens; 
     FIG. 4 show the view finder of the present invention which is comprised of an object lens, a mirror lens, a reticle lens which has a broader width than ordinary reticle lenses to have enough room for more than one frame to be provided separately and juxtaposed, and an eyepiece lens; FIG. 5A shows an example of the present invention with the mechanism which changes the film format coupling the sliding movement of the reticle lens with the 35 mm format frame in the viewing position keeping an upper masking arm pulled up and a lower masking are pulled to fully expose the film plane for a full size 35 mm format; and 
     FIG. 5B shows an example of the viewfinder of the present invention with the mechanism which changes the film format coupling the sliding movement of the reticle lens with the panorama format frame in the viewing position keeping the upper and lower part of the film plane to form the panorama format instead of the full size 35 mm format. 
     Notations 
     The various parts shown in the drawings are identified with reference numerals as follows: 
     FIG. 1 
     1. Object lens 
     2. Mirror lens 
     3. Reticle lens 
     4. Eyepiece lens 
     FIG. 2 
     5. Frame for standard 35 mm format 
     6. Frame for panorama format 
     7. Frame for HDTV format 
     FIG. 3 
     8. Frame for standard lens 
     9. Frame for wide lens 
     10. Frame for telephoto lens 
     FIG. 4 
     11. Object lens 
     12. Mirror lens 
     13. Reticle lens with broader width 
     14. Eyepiece lens 
     FIG. 5A 
     15. Object lens 
     16. Mirror lens 
     17. Eyepiece lens 
     18. Reticle lens with two frames 
     19. Panorama format frame 
     20. 35 mm standard format frame 
     21. Lever 
     22. Upper gear 
     23. Pin 
     24. Upper rack 
     25. Upper masking arm 
     26. Lower gear 
     27. Lower rack 
     28. Lower masking arm 
     29. Picture taking lens 
     FIG. 5B 
     19. Panorama format frame 
     25. Upper masking arm 
     28. Lower masking arm 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIG. 4 the viewfinder of the present invention is comprised of an object lens (11), a mirror lens (12), a reticle lens (13) which has broader width than ordinary reticle lenses to have enough room for more than one frame to be provided separately and juxtaposed, and an eyepiece lens (14). 
     The reticle lens (13) can move from right to left or left to right so that one of the frames provided on the reticle lens (13) can be selected and fixed in the viewing position. The reticle lens (13) is moved to a position dependent upon the selected format or the selected one of interchangeable lenses. 
     Whenever a format is selected or a lens is selected and fixed in position, one of the frames provided on the reticle lens (13) which matches with the selected format or the selected lens is placed in the viewing position. Also, whenever a specific frame is selected from the various frames provided on the reticle lens (13) and is fixed in the viewing position, frame marks establishing the size of the viewing area dependent upon the selected one of the formats or lenses are moved into the corresponding picture taking position. 
     FIG. 5A shows an example of the viewfinder of the present invention with the mechanism which changes the film format coupling to the sliding movement of a reticle lens (18) and in its state that the 35 mm format frame is in the viewing position keeping the upper masking arm pulled up and the lower masking arm pulled down not to cover any part of film plane keeping the film plane entirely open for a full size 35 mm format. 
     As shown in FIG. 5A, the viewfinder is comprised of an object lens (15), a mirror lens (16), an eyepiece lens (17) and a reticle lens (18) which has broader width than ordinary reticle lenses, on which the frame of a panorama format (19) and the frame of a 35 mm standard format (20) are provided separately and juxtaposed, and the reticle lens (18) is fixed on a lever (21) which slides left to right or right to left, and the lever with the reticle lens (18) is connected with an upper gear (22) through a pin (23) provided on the upper gear, and the upper gear engages with an upper rack (24) provided on an upper masking arm (25) and also engages with a lower gear 926) which engages with a lower rack (27) provided on a lower masking arm (28). 
     In the mechanism shown in FIG. 5A, when the lever (21) moves left to right, the upper gear (22) rotates clockwise and the rotation is transferred to the upper rack (24) and the upper rack (24) moves down and the upper masking arm (25) comes down, and at the same time the rotation of upper gear is also transferred to the lower gear (26), and the lower gear rotates counterclockwise and moves the lower rack (27) up and the lower masking arm (28) moves up too, thus when the panoramic frame is selected and comes in the viewing position, the film plane is covered by the masking arms so that the film plane may form the panoramic format instead of the full size 35 mm format. 
     As can be seen in FIG. 5B, the viewfinder of the present invention is shown with the format changing mechanism changed from the state of FIG. 5a in which 35 mm format frame is in position, to the state in which the panorama frame is in position and the film plane is covered by the panorama masking arms to define the panorama format on the film plane. 
     From the above, it will be apparent to one skilled in the art that various alternatives to the embodiments described may be employed without departing from the principles of the invention.