| 摘要 |
The shutter of a still camera is normally held in a closed and cocked position by a lever which is biased by a torsion spring to bear against a pivotable impeller. The latter can be cocked by the film transporting mechanism and is normally held in the cocked position by the camera release member. When the release member permits the impeller to move to its uncocked position, the latter strikes against the pin of a piezoelectric device to thereby fire a flash lamp or an electronic flash for artificial illumination of the subject. The lever is provided with an adjustable cam which is located in the path of movement of the impeller to its uncocked position so that the impeller engages the cam and disengages the lever from the shutter. The shutter opens a preselected interval of time ahead of the generation of artificial light, and the length of such interval is determined by the distance between the uncocked position of the impeller and that intermediate position in which the impeller engages the cam to disengage the lever from the shutter.
|
