GB746674A - Improvements in or relating to photographic cameras - Google Patents

Abstract

746,674. Photographic cameras with Interchangeable objectives and range- and/or viewfinders. LEITZ GES., E. Oct. 9, 1953 [Oct. 9, 1952], No. 27843/53. Classes 97 (1) and 98 (1). In a camera having interchangeable objectives of different focal lengths wherein each objective carries a device which, on securing the objective to the camera body engages with and moves automatically an actuating means which sets an interchanging means to render visible in a range- and/or view-finder the appropriate one of two or more sets of field border lines, manually operable means are provided for actuating the interchanging means to render visible in the finder any one of the sets of border lines at will, thereby facilitating the selection of a focal length suited for taking the subject. In a camera having a coincidence type short home base rangefinder of the kind involving one reflected beam from a window 6 and a direct beam from a window and coupled to the camera lens focusing mount 9, the coincidenceproducing member of the rangefinder being either the base-defining reflector 19b (Fig. 4), or a lens 19a in the reflected beam (Fig. 2), an opaque plate 16 having a transparent central aperture 16b for the reflected beam and two rectangular transparent frames 16a is mounted behind a window 7 so as to be viewed by reflection in the rhomb prism 12 and is movable diagonally between guides 21 against a return spring 22 by the rangefinder controlling lever 24 engaging a lug 23 on the frame of the plate. On applying a chosen interchangeable lens to the camera, a lug on the lens mount which lug may be one of the securing bayonet joint lugs displaces against spring action through a spring-urged slide a rod 35 having a slotted arm 34 engaging an upstanding finger 32 on a mask 17 pin-and-slot mounted on the plate 16 for movement diagonally across it whereby framing slits 17a in the mask register with one or other of the transparent frames 16a in the plate 16, the mask 17 having an aperture 17b large enough not to obscure the aperture 16b. To determine which lens is most suitable, the mask 17 may be displaceable by rotation against a return coil spring of a knob 8 on a shaft bearing face cams 51, 52 struck out from a disc 50 and adapted to bear against shoulders 35b, 35c respectively on the rod 35. When the objective is removed, the spring-loaded members of the rangefinder are locked by the rod 35 entering a recess in the disc 50. In a modification, (Fig. 7, not shown), the plate 16 and mask 17 are replaced by a pivoted sector carrying masks of different sizes in front of the window 5, a rack on an arm carried by the rod 35 engaging a pinion secured coaxially to the sector. In another embodiment (Fig. 8, not shown), the slide engaged by the lens mount lug directly adjusts the view-finder mask and manual operation of the mask is effected by limited manual rotation of the lens mount on depressing a latch locking the mount. Instead of the framing slits being on flat plutes they may be on one or more drums. Specification 695,397 is referred to.