| 摘要 |
PURPOSE:To make the closing operation of a shutter quick and to decrease exposure errors by the constitution wherein shutter blades are opened by the rotation of a ring while a magnet for controlling is held attracted and the shutter blades are closed while the magnet is held released of the attraction. CONSTITUTION:One end of a driving arm 20 for opening and closing of blades is pivoted to an immobile member by means of a fulcrum shaft 27, and the other end thereof is connected to the armature 29 of a magnet 28 for controlling. When a ring 9 is turned to open shutter blades 4a, 4b and a coil 31 is no longer energized, the armature 29 is detached from a yoke 30. In the exposure operation of the blades 4a, 4b, the blades 4a, 4b open in accordance with the rotation of the ring 9; therefore, the exposure is started relatively slowly, but when a command for ending the exposure is emitted upon attainment of the prescribed exposure value, the shutter is closed quickly by the releasing of the magnet 28 from attraction after a prescribed operation delay time. |
