| 摘要 |
PURPOSE:To make the titled lens compact and to prevent performance deterioration due to a large view angle at a zooming position of a wide angle end by constituting four lens groups consisting of negative, positive, negative, and positive lens groups from the object side and moving the 1st, 2nd and 3rd lens groups independently at the time of zooming. CONSTITUTION:The titled zoom lens is constituted by the 1st lens group with negative refractive power, the 2nd lens group with positive refractive power, the 3rd lens group with negative refractive power, and the 4th lens group with positive refractive power arranged from the object side and the 4th lens group is fixed during zooming. The 1st lens group is the closest to the 2nd lens group at the telephotographic end and the 3rd lens group is the closest to the 4th lens group at the wide angle end. When at the zooming from the wide angle end to the telephotographic end, the 2nd lens group is moved in the object side direction and the 3rd lens group is also moved in the object side direction similarly to the 2nd lens group. Thus, controlling the ratio of moving distance of the 3rd lens group to the 2nd lens group makes it possible to perform both compact constitution and high performance easily. |
