| 摘要 |
The camera shutter comprises two shutter blades which have first opening forming portions and second opening forming portions capable of alternatively forming two exposure openings different in area on an exposure aperture. These shutter blades are opened and closed by a shutter blade opening and closing lever which can be retained at a neutral position by a closing spring. The shutter blade opening and closing lever is turned by a motor which starts from the neutral position rotates in one of two directions opposite to each other. The lever is equipped with a opening spring capable of exerting a resilient force in the rotating directions of the opening and closing lever. The resilient force of the opening spring is weaker than that of the closing spring. The first opening forming portions form an exposure opening when the motor is started in a first direction and the second opening forming portions form an exposure opening when the motor is started in a second direction. Sizes of the exposure openings are adjustable by turning an adjustable eccentric stopper. This camera shutter can perform accurate and stable exposure operations though it has a simple construction and can be manufactured at a low cost.
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