| 摘要 |
An apochromatic lens system which includes, in this order from the object, a positive first lens group and a positive second lens group; wherein the following conditions are satisfied: nu I+<80(1) nu II+>70(2)1.1<fI/f<2.0(3)wherein nu I+ designates the largest Abbe number of a positive lens element in the first lens group; nu II+ designates the largest Abbe number of a positive lens element in the second lens group; fI designates the focal length of the first lens group; and f designates the focal length of the entire lens system.
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