| 摘要 |
PURPOSE:To detect a focus position without contacting by operating the electric signal output of a magnetoelectric transducer to calculate the focus position of a focusing optical system. CONSTITUTION:A permanent magnet 24 is provided in the upper rear end face of a lens holding frame 23 joined with a photographic lens 13 which is moved backward and forward along an optical axis O for a fixed frame 22 in accordance with turning of a distance ring 21 of a lens barrel 12. In the side of a camera body 11, a Hall element 25 is provided in the position which is near the lens mount of a fixed member 11a, which supports a focusing screen 15 and a pentagonal prism 16, and faces the permanent magnet 24. The distance from a film surface to an object 3 is obtained in accordance with the distance between the permanent magnet 24 and the Hall element 25 at the time when a photographic lens 13 is fed out in accordance with the object distance, the distance between the permanent magnet 24 and the Hall element 25 at the time when the photographic lens 13 is focused on an object of infinity, etc. |
