GB1462437A - Photographic miniature cameras with built-in viewfinder - Google Patents

Abstract

1462437 Reflex cameras PENTACON DRESDEN KAMERA-UND KINDWERKE VEB 2 Dec 1974 [7 Dec 1973] 52095/74 Heading G2A A photographic miniature camera has an optical picture taking and viewing system including an objective lens 4 or 20, a ray divider 5 or 19, situated in the path of the light from the subject, an image field lens 9 or 21, a Schmidt prism 10 or 22, and a view-finder eye-piece 11 or 23. In one embodiment, Fig. 1, rays from the subject pass through a camera opening 6, through a partially translucent mirror coated surface 12 of the ray divider 5, through the objective lens 4 to the image-plane 2. Part of the incoming rays is reflected by the surface 12 and then total reflected by the front surface of the ray divider 5 to be directed upwardly at 45 degrees to the incoming rays. The light passes through a view-finder lens 7 and the image field lens 9 into the prism 10 and hence to the eye-piece 11. Between the lenses 7 and 9 is disposed a partially translucent mirror coated plate or cube 8 which reflects some of the rays through 90 degrees to a photo-electric cell 14 of a photo-electric exposure measuring device. A camera shutter 24 is disposed behind the ray divider 5. In another embodiment, Fig. 2, the ray divider 19 is disposed between the objective lens 20 and the image gate 18.