Patent ID: 7542219

Claim:
An intermediate telephoto lens system comprises a positive front lens group, a variable-aperture diaphragm, and a positive rear lens group, in this order from an object, without another lens intermediate said positive front lens group and said positive rear lens group, wherein said positive front lens group comprises a positive first lens element L 1 , a positive second lens element L 2 and a negative third lens element L 3 , in this order from the object; wherein said positive rear lens group comprises cemented lens elements having a negative fourth lens element L 4 and a positive fifth lens element L 5 , and a positive sixth lens element L 6 , in this order from the object; and wherein said intermediate telephoto lens system satisfies the following condition: 2.0<f/f 12 <3.0 wherein f designates the focal length of the entire intermediate telephoto lens system; and f 12 designates the combined focal length of said positive first lens element L 1 and said positive second lens element L 2 .