Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Folding
Patent
1978-06-26
1981-05-05
Sacher, Paul A.
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Folding
351 8, 351 9, 351 13, 351 16, A61B 314
Patent
active
042655188
ABSTRACT:
Apparatus herein disclosed comprises a photographing system having an optical system of variable magnification and an illumination system having a light source for photographing and a light source for observing. In the apparatus, the existing photographing magnification of the optical system is detected and the quantity of light incident upon a film or a finder visual field is controlled depending upon the detected magnification so as to obtain an optimum exposure to the film of the photographing system or to maintain the brightness of the visual field constant. To attain the control of quantity of light, light passing through the illumination system or light passing through the optical system is gradually reduced with widening of the angle of field. Alternatively, intensity of light emitted from the light source for observing or light emitting time of the light source for photographing is altered depending upon the detected magnification.
REFERENCES:
patent: 3549250 (1970-12-01), Pantenburg
patent: 3915564 (1975-10-01), Urban
Canon Kabushiki Kaisha
Sacher Paul A.
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