GB574993A - Improvements in or relating to a combined range finder and view finder or a range finder alone - Google Patents

Abstract

574,993. Range - finders and viewfinders. KODAK, Ltd. Feb. 21, 1944, No. 3209. Convention date, March 11, 1943. [Classes 97 (i)and 98 (i)] In a combined view-finder and rangefinder an adjustable objective 10 forms an image in a primary image plane P in which there are a field lens 16 and means such as wedges 15, 15<1> arranged with their bases on opposite sides of the optical axis for deviating rays falling on them in opposite directions so that three overlapping images will be formed in a plane conjugate to the objective 10 with reference to the field lens 16, in which plane a selector stop and erector lens 11 select a portion of the overlapping images which are viewed by the eye piece 14. The image as viewed at 21 is shown in Fig. 5 and comprises the field of view with, in the centre, a laterally split image of the object being ranged upon. When the objective is focussed to bring the image plane into the plane of the wedges and field lens, coincidence is obtained and the boundary of the range field disappears. The field lens and wedges may be moulded from transparent plastic material, Fig. 4 (not shown). The device may be applied to a camera, in which case the objectives of the camera and the rangefinder are the same, the film being supported in the primary image plane of the camera objective, and, by connecting the range-finder and camera objectives by a lever mechanism, the camera will be in correct focus when coincidence is obtained in the rangefinder, Fig. 8 (not shown). When the device is used as a rangefinder only the deviating means covers the whole area of the field lens.