In a single-lens reflex camera having an objective lens, a focusing screen and a view finder, a photodetector array is arranged to receive a central part of an object image formed by the objective lens and a focusing condition of the objective lens is detected by calculating an evaluation function from...http://www.google.fr/patents/US4483602?utm_source=gb-gplus-shareBrevet US4483602 - Apparatus for detecting a focusing condition of an objective lens
Apparatus for detecting a focusing condition of an objective lens
