| 摘要 |
PURPOSE:To make the whole zoom lens compact and high performance and to keep a projected pupil position practically constant while fixing a stop to omit a means for moving the stop by moving lens groups arranged on the image side from the stop in order to zoom. CONSTITUTION:The 1st positive lens group L1 to be moved at zooming, the 2nd negative lens group L2 having similar function to the 1st lens group L1, the stop S, the 3rd positive lens group L3 to be fixed at zooming, the 4th negative lens group L4 to be moved at zooming, and the 5th positive lens group L5 to be fixed at zooming are arranged in order from the object side. Thus, the 4th lens group L4 which is one of plural moving lens groups L1, L2, L4 for zooming is arranged on the image side from the stop S and is moved so that the magnification beta<s> of pupil light rays related to the lens group L4 is included in a range of beta<s>=-1+ or -delta to prevent influences due to the variation of the projected pupil position practically. |
