LIGHT QUANTITY ADJUSTING DEVICE, LENS DEVICE, AND IMAGE PICKUP DEVICE

摘要

PROBLEM TO BE SOLVED: To solve the problem that resolution decreases due to a shift in the position of an image formation plane caused because of the thickness and refractive index of an ND filter right before the filter covers a light passage opening S completely. SOLUTION: This light quantity adjusting device has a dimming filter 14 provided to a light-shield blade 131c or 131d varying the opening area of the light passage opening S through opening/closing operation, and this dimming filter has a main filter part 14a which has light transmissivity corresponding to dimming effect that this dimming filter needs to have and a non-filter part which has opening/closing-directional with H needed to completely cover the opening area S' of the light passage opening more on the tip side than the area covered with the main filter part in the closing direction and also has constant light transmissivity nearly without dimming effect and is substantially equal in optical-axis-directional thickness and refractive index to the main filter part.