| 摘要 |
PROBLEM TO BE SOLVED: To make inexpensively realizable accurate control of transmissivity by using a high-accuracy and high-reliability ND filter capable of obtaining the transmissivitys in many stages. SOLUTION: This device 1 is equipped with a diaphragm blade moving on a plane orthogonal to the optical axis of a photographing lens and varying the diaphragm aperture, a diaphragm blade driving mechanism driving the diaphragm blade, the ND filter 24 moving on the plane orthogonal to the optical axis X-X of the photographing lens and varying transmitted light quantity, and an ND filter driving mechanism driving the ND filter 24. In such a case, the ND filter 24 is formed so that many dots 34 having the same density are formed on a transparent sheet 33 and the transmitted light quantity is changed in a moving direction stepwise or non-stepwise.
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