FOCUS DETECTOR FOR CAMERA

摘要

PROBLEM TO BE SOLVED: To detect focus extending over a wider visual field by detecting phase difference obtained by reflecting subject luminous flux transmitted through a photographing lens by an optical path switching element arranged in front of an equivalent surface to a film and transmitting it through a main mirror and guiding it to a focus detection optical system. SOLUTION: This focus detector for camera is constituted so that one part of the subject luminous flux transmitted through the photographing lens 11 is reflected in a different direction from a film surface by the main mirror 12. The luminous flux reflected by the mirror 12 is further reflected by the optical path switching element 16 positioned in front of a focusing plate 17 being the surface equivalent to the film surface. Then, the luminous flux reflected by the element 16 is transmitted through the mirror 12 and received by the focus detection optical system 21. Thus, the focus is detected.