Camera having a focus detecting apparatus

摘要

In a camera provided with a focus detecting apparatus in which the object light passed through a photo-taking lens is limited in its passage area by a field mask, the secondary image of an object to be photographed is obtained by a secondary imaging optical system and the secondary image is received by a line sensor and the imaging condition of the photo-taking lens is detected on the basis of the photoelectrically converted output of the line sensor, the opening area of the field mask is set so that the secondary image of the object to be photographed is directed to the both sides of the line sensor, and spot photometering sensors are disposed on the both sides of the line sensor and in the area to which the secondary image is applied, so that the photometering center of gravity is positioned substantially on the line sensor.