The telephoto lens system consisted of only two pieces of optical elements made of FK1 glass has an equivalent optical performance to the traditional telephoto lens system made of five pieces of optical elements made of defferent kinds of glass.

• 给出了仅使用1种材料FK1、2片型的长焦物镜系统设计结构，并将此设计结果与传统的5片型、5种材料的纯折射长焦物镜的光学性能进行了比较。