| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-performance retrofocus type wide angle lens system which is thinner (smaller in size), whose aberrations, especially, coma aberration, distortion aberration and chromatic aberration are satisfactorily corrected, and whose field angle is about 70°. SOLUTION: In the wide angle lens system comprising a negative front group and a positive rear group in order from an object side, the front group comprises a negative first-a lens group and a positive first-b lens group in order from the object side. The wide angle lens system satisfies following conditional expressions (1) and (2). (1) -0.8<f1a/f1b<-0.1, (2) 0.6<f/fR<1.1, provided that f1a; focal distance of the first-a lens group, f1b; focal distance of the first-b lens group, f; focal distance of the entire system, and fR; focal distance of the rear group. COPYRIGHT: (C)2007,JPO&INPIT
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