Patent ID: 6313955
Filing Date: 2001-11-06
Classification: G02B

Abstract:
A rear-focusing telephoto lens system comprising a positive front lens group, and a positive rear lens group, in this order from an object;wherein said front lens group comprises at least two positive lens elements, each of which has a large-curvature convex surface facing toward said object, and a negative lens element having a large-curvature concave surface facing toward an image;wherein said rear lens group comprises at least one lens element which has a convex surface facing toward said object, and is positioned at the most object-side in said rear lens group; andwherein upon focusing, only said rear lens group moves along the optical axis, and said lens system satisfies the following condition:0.5<f/fF<0.8whereinf designates the focal length of the entire lens system; andfF designates the focal length of said front lens group.