GB808791A - Depth of focus indicators in photographic cameras - Google Patents

Abstract

808,791. Depth of focus indicators. ZEISS-STIFTUNG, C., [trading as ZEISS, C., [Firm of]]. Jan. 14, 1957 [Jan. 14, 1956], No. 1282/57. Class 98(1) A depth of focus indicator in a photographic camera comprises adjustable pointers indicating the depth of focus on a distance scale carried by a focusing ring, the pointers being carried by ring segments which are turned in opposite directions about the camera axis by cam means which are moved in the direction of the camera axis when the diaphragm setting ring is adjusted. As shown in Fig. 2, the pointers 5, 6 are carried by ring segments which are engaged by the curved surfaces of a cam 9 slidable in an axially extending groove 11 in a fixed ring carrying an index 3 for focusing scale 1 and an index 4 for the diaphragm scale on aperture setting ring 13. This ring has a curved slot 14 engaged by a pin 12 on cam 9 so that, as ring 13 is retracted to set a new diaphragm aperture, cam 9 moves axially and turns the ring segments to adjust the separation of pointers 5, 6 which indicate on scale 1 the depth of focus corresponding to the new aperture. In another form, two cams are provided each cam being engaged with a different slot in diaphragm ring 13 so that the cams are successively actuated as ring 13 rotates.