| 摘要 |
PURPOSE:To increase the sensitivity of a camera, by freely loading/unloading a near-infrared ray filter externally. CONSTITUTION:A near-infrared ray cut filter 3 and a transparent member 5 having a thickness optically equivalent to that of the filter 3 are inserted to a holding frame 6, the assembly is rotated by taking a shaft 7 as an enter and either one of the filter 3 or the member 5 is inserted to the optical path of the for image pickup optical system. Thus, without change in the focus point of the image pickup optical system, the filter 3 can be loaded or unloaded to/from the optical path. In case of an objective, having normal illuminance, the member 5 is inserted to the optical path for image pickup with good color reproducibility, and in case of the objective having a low illuminance, the filter 3 is inserted to prevent the deterioration in the S/N. |
