| 摘要 |
PURPOSE:To move a distance measuring visual field to an arbitrary position to detect the focus by moving a slit member and moving the aperture part of a visual field mask to an arbitrary position in a finder visual field and receiving the light with two photodetectors. CONSTITUTION:A slit member 2 having plural slit aperture parts 2a arranged at intervals of a certain length near a predeterminate image forming surface of an objective lens 1, a visual field mask 3 which is arranged in the vicinity of the slit member 2 and has the aperture part, first light receiving means 14 and 15 which receive the object light passing through both aperture parts, and a first driving means which moves the slit member 2 are provided. The visual field mask 3 is moved to an arbitrary position in a plane parallel with the predeterminate image forming surface of the objective lens 1. In a focus detecting system, the slit member 2 is moved and the phase of the change of output signals from photodetectors 14 and 15 is detected in accordance with the movement to detect the focus. Thus, the distance measuring visual field is moved in an observation visual field to detect the focus in a desired position. |
