| 摘要 |
PROBLEM TO BE SOLVED: To provide a diaphragm device by which the lowering of resolving power and the unevenness of light quantity on an image plane due to the influence of diffraction are prevented even for a very high-luminance subject, which is easily manufactured, whose manufacture cost is low and which has high durability to an environmental condition such as humidity. SOLUTION: In the diaphragm device which is provided with recessed notches at the respective edges of two diaphragm blades moving in an opposite direction to each other on a plane orthogonal to an optical axis, and where a diaphragm aperture is formed by making the recessed notches face to each other, a 1st ND filter consisting of (n) ND filter members is arranged at least at a part of the 1st recessed notch, and a 2nd ND filter consisting of (n) ND filter members is arranged on the edge side of the 2nd recessed notch, and a 3rd ND filter consisting of 2n ND filters is arranged on the inner side of the 2nd recessed notch.
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