| 摘要 |
PURPOSE:To provide a focus detector by which an image with high quality can be photographed and which is made as compact as possible. CONSTITUTION:Luminous flux for detecting a focus receiving an image forming action by a photographing lens 11 is guided to the detection aperture part 17 of the bottom part 12a of a mirror box 12 by a sub-mirror 15 in the box 12 and made incident on an image reforming optical system securing focusing accuracy by a condenser lens 18, a pair of brightness diaphragms 20a and 20b and image reforming lenses 21a and 21b where respective apertures corresponding to respective incident pupils are formed and photoelectrical conversion means 22a and 22b corresponding to the apertures of the respective diaphragms 20a and 20b from the aperture part 17. Then, two-surface light shielding walls 23a and 23b are arranged between the scheduled image forming surface 16 of the lens 11 in the box 12 and the bottom part 12a of the box 12 so that they are not in parallel with an image pickup surface 13 in order to detect the focus by detecting the phase difference of an output signal expressing the distribution of light intensity from the conversion means 22a and 22b corresponding to the respective incident pupils. |
