GB454704A - Improvements in or relating to photo-electric photographic exposure meters - Google Patents

Abstract

454,704. Photographic exposure meters. METRAWATT AKT.-GES. FABRIK ELEKTRISCHER MESSGERAETE, 52, Schoppershofstrasse, Nuremberg, Germany. Feb. 24, 1936, No. 5528. Convention date, March 2, 1935. [Class 98 (i)] A photo-electric exposure meter comprises electrical indicating means controlled by at least one photo-electric element, a scale cooperating with the indicating means, means for setting the scale in accordance with a given stop value and a given emulsion sensitivity, means for altering the sensitivity of the photoelectric element to adapt the indicating means to different ranges of measurement, and means for setting the scale in accordance with the different ranges. As shown in Fig. 1, a uniform rotatable exposure time or kinematographic film feeding speed scale d is adjustable by the handle a and is arranged over the non-uniform scale e of the electric meter, scales d and e being connected by lines. On the handle a is a pointer b adapted to be set in accordance with the emulsion sensitivity and having an index mark adapted to be set in accordance with the stop value. An attachment f, Fig. 5, provided with one or more photo-electric cells il can be plugged into the casing f in parallel with the built-in photo-electric element i. As shown in Fig. 6, the handle a or the pointer b has two index marks g and g<1>, moving in front of the scale of stop values, the distance between which corresponds to the logarithm of the ratio between the sensitivities of the two photo-electric elements used. The mark g<1> may comprise a pointed arm which may or may not be adjustable relative to the pointer b and which may be clamped relative to the pointer b. The arrangement is applicable to exposure meters in which the measuring range is altered by varying the active surface of the photo-electric element by a diaphragm. Specification 453,864 is referred to.