Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Patent
1977-07-11
1979-03-06
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
250226, H01J 3150
Patent
active
041432657
ABSTRACT:
An arrangement for determining exposure parameters to obtain correct exposure of a film while photographing an object in which a lens produces a primary image of the object, which is converted into a secondary image by an electronic image converter. The converter has a contrast range and gamma value corresponding to the film. A light attenuation device influences the brightness of the primary image and has a final control element which displays the exposure parameters on a suitably calibrated scale. The image converter may have a photoactivated liquid-crystal light cell, and behind the lens may be located devices for splitting the optical path into three partial optical paths, each having an additive color extraction filter with a pass band in the red, green and blue range and an image converter. The secondary images generated by the image converters are superposed after a renewed filtering of these images by suitable additive color filters.
REFERENCES:
patent: 2521093 (1950-09-01), Rath
patent: 3652154 (1972-03-01), Gebel
patent: 3864037 (1975-02-01), Johnson
Fogiel Max
Gossen GmbH
Nelms David C.
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