GB382528A - Improvements in or relating to photographic cameras - Google Patents

Abstract

382,528. Photographic cameras fitted with telemeters. DEHN, F. B., 103, Kingsway, London.-(Zeiss Ikon Akt.-Ges. ; 72, Schandauer Strasse, Dresden, Germany.) March 14, 1932, No. 7579. [Class 98 (i).] In a camera of the kind in which the focusing of the objective is controlled by a telemeter of the double-image or split-image type, a cam or cam groove moved with the objective during focusing effects movement of the adjustable part of the telemeter through transmission means which includes a second cam or cam groove. As applied to a camera fitted with baseboard focusing mechanism, the lens carrier a, Fig. 1, is fitted with a rail b carrying a cam c co-operating with a lug f on a spring-loaded lever d which turns on a pin s in the housing of a telemeter h disposed vertically in the camera body, and carries a cam disc k against which the lower, pivoted mirror g of the telemeter is pressed by a spring l. A similar arrangement may be used if the telemeter is one with an adjustable lens or prism, or has small matt screens for receiving the images. The lever d is automatically folded into the camera body when the camera is closed, and the cam c may be hinged about its vertical or horizontal edge for the same purpose. As applied to a camera having a lens in a focusing mount, the rotatable part of the mount m, Fig. 3, carries on its periphery a cam b<1> cooperating with a spring-loaded lever d<1> turning on a pin s in the housing of a telemeter h mounted on the lens carrier. A cam disc k on the lever d<1> actuates the mirror g of the telemeter as in the first construction. A modification of the second construction for inextensible cameras is referred to, in which the telemeter is arranged in the camera housing. The cams may be curved or straight, according to requirement. The telemeter, instead of forming a separate part, may be built into the camera housing or objective carrier. To compensate for wear, or to adapt the device for a change of camera lens or for fine compensating when using lens filters &c., the cams may be adjusted vertically or horizontally by screws, or the lug f may be adjustable, or the connections between the lever d and cam k may be adjustable. Interchangeable cams may be provided for use with different objectives. The device may be modified so that focusing is effected by operating the telemeter instead of operating the focusing mechanism of the lens. The Specification as open to inspection under Sect. 91 (3) (a) states also that if the cam b<1>, Fig. 3, is made sufficiently long, the second cam k is unnecessary ; and that when adjusting the telemeter for near objects, a special lens may be employed instead of adjusting the objective. This subject-matter does not appear in the Specification as accepted.