| 摘要 |
PURPOSE:To obtain superior color reproducibility by arranging plural moving lens group for focusing on the image side from a stop and moving these lens groups at the time of focusing while keeping a projected pupil position constant. CONSTITUTION:The 1st positive lens group L1 fixed for focusing, the 2nd negative lens group L2, a stop S the 3rd positive lens group to be moved for focusing, and the 4th positive lens group L4 are arranged successively from the object side. When focusing is to be executed by moving the lens groups L3, L4 arranged on the image side from the stop S, the ratio of these moving variables are set up so that the image points by the lens groups L3, L4 when the stop S is regarded as a subject are fixed. Even if the lens groups L3, L4 on the image side from the stop S are moved to focus, the projected pupil position is kept constant and superior color reproducibility is obtained. |
