A telephoto lens system includes a positive first lens group, a positive second lens group, a diaphragm, a negative third lens group constituting a focusing lens group, and a positive fourth lens group.
The first lens group includes a positive first lens element, a positive second lens element, and a negative third lens element. The second lens group includes a negative or a positive fourth lens element and a positive or negative fifth lens element which are cemented to each other. The third lens group includes a positive or negative sixth lens element and a negative or positive seventh lens element which are cemented to each other. The fourth lens group includes one positive eighth lens element. Upon focusing on an object at infinity to an object at a closer distance, the third lens group is moved toward the image. The telephoto lens system satisfies the following conditions:
1.4<f/f1<1.8 (1)
2.4<f/f12<3.0 (2)
−5.5<
f/f3<−3.5 (3)
- wherein f: a focal length of the telephoto lens system; f1: the focal length of the first lens group; f12: the combined focal length of the first lens group and the second lens groups; and f3: a focal length of the third lens group.