Patent GB-830656-A (GB)
Title: Improvements in or relating to photographic cameras with interchangeable lenses
IPC: G03B17/02
Filed: 1956-09-05
Abstract: 830,656. Photographic cameras. DECKEL, H., and DECKEL, F. W. Sept. 5, 1956 [Sept. 9, 1955], No. 27138/56. Class 98(1) A photographic camera having means for mounting interchangeable lenses of different focal length and means for focusing these lenses is provided also with a ring carrying a series of distance scales, each corresponding to a lens of different focal length, and with a further ring surrounding the scale carrying ring and having a viewing window, the two rings being relatively movable so that the scale corresponding to the lens that is to be used registers with this window. As shown in Fig. 2, a lens and shutter assembly 10 is coupled bayonet fashion to a cylindrical member 18, which is slidable on a guide 20 attached to the camera front and has threaded thereon a collar 28. This collar is rotatably held on the camera by a bush 32 and has a pin and slot connection with a focusing ring 36 so that the collar and ring are rotatable together for focusing and relatively slidable by manual or automatic means to allow the ring 36 to take up any one of three axial positions defined by detent 52 and notches 54. Corresponding to each axial position of ring 36 a different one of three distance scales 38, 38a and 38b formed on the periphery of the ring, registers with a viewing window 42 in the bush 32. A depth of field indicator is also provided and comprises movable pointers 46, 48 which project from the camera to overlie the window 42 and which are movable by the diaphragm setting member, e.g. as described in Specification 793,178. The detent 52 may be replaced by a locking lever, pivoted in a slot in the focusing ring 36 and selectively engageable with those axially spaced grooves in the periphery of the collar 28. In a second form, rotation of the collar 28. focuses the attached lens, the distance scales are formed on the periphery of the collar and a non-rotatable sleeve provided with a viewing window is axially movable to any one of three detent defined positions to bring this window into registry with the distance scale corresponding to the lens in use. The scales may be spaced around the periphery of a focusing ring which is rotated to bring the selected scale into registry with the depth of field indicator and is then coupled by a spring loaded detent with the collar 28 so that by rotating the ring and collar the lens can be focused. Again, the scales may be spaced around the periphery of the collar, the appropriate scale being selected by rotation of a ring relative to the collar to register a window in the ring with said scale. In a further form, Fig. 9, the collar 28 carries two axially spaced distance scales on its periphery and between it and the focusing ring 36 is a spring loaded ring 84 having an aperture 86 therein which registers with the scale 38 or 38a depending upon the depth of a recess 88 in the lens mount which is being attached. Alternatively the scales may be formed on a member which is axially displaceable relative to a viewing window in the focusing ring 36 to an extent depending upon the depth of a recess in the lens mount. Another form is described in which two scales are provided on a ring 110 which is normally located by spring loaded detent with one scale registering with an aperture in the focusing ring but which, during the mounting of another lens mount, is rotated by engagement with a pin projecting from the mount to register the other scale with said aperture. The two scales may also be mounted on the collar so that one normally registers with an aperture in a member interposed between the collar and the focusing ring, this member being rotated when the other lens is mounted to bring the aperture therein into registry with the other scale.