| 摘要 |
PROBLEM TO BE SOLVED: To provide a diaphragm device which is made compact and of which constitution is simple. SOLUTION: A base plate is provided with a lens aperture 1, and a driving lever 2 that is displaced along the base plate from a neutral position at a specified angle. The base plate is further provided with a first aperture blade 3 having an intermediate diaphragm aperture 3b of which size is smaller than that of the lens aperture 1 and displaced to a position at which it covers the lens aperture 1 and a position at which it is withdrawn by the driving lever 2 and a second aperture blade 4 having a minimum diaphragm aperture 4b of which size is smaller than that of the intermediate diaphragm aperture 3b and displaced to the position at which it covers the lens aperture 1 and the position at which it is withdrawn by the driving lever 2. When the driving lever 2 is at the neutral position, the first and second aperture blades 3 and 4 are set in a non-shielding state to the lens aperture 1. When either the first aperture blade 3 or the second aperture blade 4 covers a part of the lens aperture 1, the entire lens aperture 1 is covered by the cooperation of both of them so that one of them covers a part of the lens aperture 1 when the other covers the other part of the lens aperture 1.
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