| 摘要 |
PURPOSE:To obtain a compact zoom lens of high variable power by moving two of four lens groups for one power variation, and increasing the gap between two lens groups while fixing other two groups for the other power variation. CONSTITUTION:A lens group II for variable power and a lens group III for image plane compensation are moved as shown within a variable power range AB as shown by arrows while a lens group I is fixed during the power variation to make one power variation. Further, the lens group III and a lens group IV for image formation are moved within a variable power range AA' as shown by an arrow with the lens groups I and II fixed to that the gap is increased, thus performing the other power variation. Consequently, extra space need not be secured in the lens system previously and the power is increased efficiently. |
