| 摘要 |
PURPOSE:To detect the focus for less defocusing in an arbitrary distance measuring visual field and to detect the focus for much defocusing in a certain distance measuring visual field on the optical axis by using two focus detecting systems. CONSTITUTION:The exit pupil of an objective lens is divided to two pairs of areas, and light quantity distributions related to an object image are formed with luminous fluxes passing one pair of first pupil areas 12a' and 13a' to constitute the first focus detecting system where the distance measuring visual field can be moved, and light quantity distributions related to the object image are formed with luminous fluxes passing the other pair of second pupil areas 9a' and 9b' to constitute the second focus detecting system where the distance measuring visual field is fixed. The first focus detecting system detects the phase of the change of output signals from photodetectors 14 and 15 corresponding to movement of a slit member 2 to detect the focus. The second focus detecting system uses the pair of second pupil areas 9a' and 9b' of the luminous flux passing an exit pupil 1a of the objective lens 1. Thus, focus detection with the distance measuring visual field varied and that with this visual field fixed are performed with a high precision. |
