| 摘要 |
PROBLEM TO BE SOLVED: To obtain a focus detector capable of two dimensionally and continuously detecting a focus in plural areas over a wide range on a photographic screen and an observation screen, and to obtain an optical instrument using the focus detector. SOLUTION: Plural light quantity distributions as to a subject image are formed by using a luminous flux passing through plural different areas separated in the pupil of the objective lens 101 by optical means 4 to 9 installed on the image plane side of the objective lens 101, and the relative positional relation of plural light quantity distributions is obtained by a photoelectric transducing element 11 constituted of plural elements. And, in the case of obtaining the focusing state in one or plural areas in a photographic visual field by using a signal from the photoelectric conversion element 11, the optical means 4 to 9 are provided with a condensing reflection mirror 4 for reflecting the luminous flux from the objective lens 101 so as to form the subject image on a prescribed plane, and a secondary image forming system 9 for forming the subject image formed on the prescribed plane on the surface of the photoelectric transducing element 11 again, and the reflection mirror 4 is constituted of a reflection plane with no rotation symmetrical axis. |
