GB936964A - Photographic cameras - Google Patents

Abstract

936,964. Photographic cameras. VOIGTLANDER A.G. Dec. 9, 1959 [Dec. 9, 1958], No. 41910/59. Class 98 (1). In a photographic camera having a viewfinder including a prism in its ray path with the camera cap, the prism carries additional optical means whereby an image of an external adjustment scale and reference mark connected to the corresponding camera setting member is formed in or adjacent the field of the viewfinder, so that an image of the scale and mark and an image of the scene may be observed simultaneously. The camera may be a twin lens or a single lens reflex camera or a kinematograph camera. As shown for a reflex camera, a pentagonal roof prism 5 erects and laterally inverts the image seen in the eyepiece 6 of the image formed on the plane focusing screen surface of the field lens 4. A prism 26 cemented on a non- silvered face 27 of the roof prism 5 directs an image of the speed and aperture scales 8, 9 on the shutter-diaphragm unit into the viewfinder eyepiece. A shaft 25 extending from the shutterdiaphragm unit and setting shutter and diaphragm to combinations representing particular light values is connected by gearing 23, 24 to a light value setting knob 22 coaxial with the rollfilm rewinding knob 14 (Fig. 1, not shown) and having a cam 21 controlling a follow-up member 18 for the pointer 17 of a photo-electric exposure meter, both the follow-up member and pointer being disposed close to the bottom face of the prism 5. The view seen by an eye at 7 is shown in Fig. 9. By arranging the supplementary prism on the lower scene finder reflecting surface 35 of the prism 5 the scales appear within the limits of the finder field, while by causing the beam forming the scale image to be reflected at the junction between surfaces 27, 35 the scales straddle the finder field boundary. A negative lens may be attached to the inlet face of the supplementary prism 26 so as to allow an image of the focusing scale 1 and depth of focus indicators 11 to be formed in the eyepiece 6. Alternatively by providing vertical extensions of the rings bearing the scales 1, 8, 9 close to the base of the face 35 of the prism 5 to which is attached a positive lens with or without an intervening wedge prism the scales may be visible at the bottom of the finder field.