GB705855A - Improvements in or relating to photo-electric exposure meters - Google Patents

Abstract

705,855. Photo-electric exposure meters. ZEISS IKON AKT.-GES. May 30, 1951 [Sept. 3, 1949], No. 12754/51. Class 98(1). [Also in Group XL(b)] In a photo-electric exposure meter of the type in which the meter movement or a part thereof is movable to provide a setting means which allows variable exposure factors to be taken into account, the meter movement or a part thereof is movable without alteration of its electrical characteristic upon movements of calibrated members of a setting mechanism which may be set in accordance with desired values of exposure factors, one of said calibrated members being mechanically connected to said meter movement or part thereof through means in the setting mechanism including a cam so shaped and arranged that in use it serves to reconcile the calibration of said calibrated members with the response characteristic of the meter movement. As shown, a meter 11 electrically connected with a photo-cell (not shown) is secured as a whole with a gear 9 to an axle 10 and is urged clockwise by a spring 14. A gear sector 8 on one arm of a lever 4 pivoted at 5 meshes with the gear while the other end of the lever is formed as a nose 6 which bears against a cam track 7 formed in the underside of the outer ring 3 of a calculator comprising rotatable rings 2, 3 and a stationary disc 1. The disc 1 carries a mark 15 against which may be read a scale 16 of film speeds on the ring 2, this ring carrying also a scale 17 of aperture values which may be read against a scale 18 of exposure times on the ring 3. In use, the ring 2 is first set to allow for the film speed and the ring 3 is then rotated until the pointer 12 of the meter is aligned with a fixed mark 13 when the appropriate combination of shutter speed and aperture may be read from the scales 17, 18. If desired, adjustment of the ring 2 may also effect adjustment of the camera shutter-speed or the diaphragm mechanisms.