Electrical focal plane shutter with mechanical control mechanism operative upon electromagnetic failure

摘要

An electrical focal plane shutter is provided of a type in which subsequent to a running of a first blind of the shutter, a second blind of the shutter is constrained from movement by an electromagnet until a desired exposure period passes, whereupon the electromagnet is deenergized to permit a running of the second blind. The electromagnet is controlled by an electromagnet control device including a light receiving element which is used for photometry. The shutter includes a shutter detent mechanism for preventing a shutter release operation when an electric storage battery contained in an associated camera is exhausted. The shutter further includes a high speed shutter operation control mechanism which assures against the instability of the operation of the electromagnet when the shutter is operating at a high speed, and also includes a manual shutter control mechanism for establishing a shutter operation period of a given length in a purely mechanical manner.