Camera system with vignetting calculation and memory means

Details Camera system with vignetting calculation and memory means Camera system with vignetting calculation and memory means

1987-03-27

1989-03-28

Nelms, David C.

Radiant energy

Photocells; circuits and apparatus

Photocell controls its own optical systems

354402, G01J 120

Patent

active

048166634

ABSTRACT:
In an apparatus for detecting the in-focus state of a photo-taking lens of a camera, a defocus signal is produced responsive to a light intensity distribution signal and is indicative of deviation between an image of an object to be photographed and a predetermined surface. An information signal is produced indicative of the effectiveness of the defocus signal. A vignetting detection signal is produced indicative of the state of vegnetting by the photo-taking lens. The information signal is compared with a threshold value to determine the effectiveness of the defocus indicated by the defocus signal, and the threshold value is changed in response to the vignetting detection signal. A photo-taking lens may include a memory that stores data indicating an inverse of a value indicative of a distance from a predetermined plane to an exit pupil of the photo-taking lens, and the data stored in the memory may be used for calculating vignetting.

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