GB796560A - Improvements relating to photographic cameras - Google Patents

Abstract

796,560. Photographic cameras. DECKEL, H., and DECKEL, F. W. May 10, 1956 [May 11, 1955], No. 14566/56. Class 98(1) In a photographic camera having a shutter speed setting ring and a diaphragm setting ring, one ring is provided with a light value scale and the other with a film speed scale co-operating therewith. Preferably, a marker is provided on the film speed scale to indicate the speed of the film contained in the camera and the light value scale is set to this member as to an index. Shutter speed and diaphragm aperture scales are also provided on the appropriate ring and co-operate with a fixed index on the camera body. After the light value has been set the shutter speed and diaphragm rings may be locked for rotation together to set any of the paired values of shutter speed or diaphragm aperture. The locking may consist in a tooth on the resiliently urged diaphragm ring engaging one of a number of notches in the shutter speed ring (Fig. 1, not shown) or the film speed marker may consist of a resilient arm 50 having a projection 52 engaging the knurling of the shutter speed ring 11 and tongues 53 engaging slots 54 in the diaphragm setting ring 12. By slightly bending the resilient arm 50 the locking may be disengaged and, by further bending, the marker becomes displaceable over the film speed scale 22. The light value scale 21 which corresponds to a similar scale in exposure meter, and the film-speed scale 22 are linear and any change by a single unit doubles or halves the exposure of the film.