AUTOMATIC FOCUSING DEVICE

摘要

PURPOSE:To reduce the range finding parallax between a finder system and a photography system by arranging a light emitting element or light receiving element at a position nearly equivalent to the primary image formation surface of the objective of a finder system. CONSTITUTION:A light receiving lens 10 and the light receiving element 11 are arranged across a photographic lens symmetrically with the objective 2 of the finder system 20. Namely, near infrared light emitted by the light emitting element 8 arranged at the position nearly equivalent to the primary image formation surface of the objective 2 is deflected by a half-mirror 9 provided on a finder optical path toward the objective 2 on the optical path and passed through a concave lens 2b and a convex lens 2a to illuminate a subject surface. Its reflected light from the subject surface passes through the light receiving lens 10 and is guided onto the position detection type light receiving element PSD 11 to form a spot image. An automatic focus adjusting device is therefore obtained which has a small visual field at the time of focus detection and facilitates the displacement of the range finding visual field of the finder system.