GB961033A - Viewfinder device connected to the objective of photographic cameras - Google Patents

Abstract

961,033. Photographic cameras. CARL ZEISS-STIFTUNG, [trading as CARL ZEISS [Firm of]]. July 1, 1960, No. 23190/60. Headings G2A and G2J. In a photographic or cinematographic camera, some of the light entering the objective is reflected into a viewfinder system, which produces a real image of the object to be photographed observable by interposing further optical means, by two mirrors located in front of the iris diaphragm of the objective and lying outside the optical axis in a single plane inclined relative to the axis. As shown two small mirrors 8, 9 disposed on a diagonal plane of a block 7 as shown in Fig. 2 reflect light from the scene through a group of lenses identical to the rear group III of the pancratic objective to a plane 15 incorporating a split-image focusing aid 16, the finder image being viewed through an erector system. The focusing aid may comprise a sheet having a series of parallel roof ridge element (Fig. 5 not shown) or two such series side-by-side with the ridges of one set in line with the valleys of the other (Fig. 6 not shown) or two side-by-side oppositely directed sets of parallel saw tooth elements having their surfaces perpendicular to the body of the sheet aligned (Fig. 4 not shown). The spacing of the mirrors 8, 9 is preferably such that the diaphragm is unobstructed at an aperture of f/8 and the refracting angles of the focusing aid are chosen so that the double images formed by the two mirrors and the focusing aid are seen in the viewfinder at the interocular distance. It is stated that the invention may also be applied to television cameras.