| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small and high performance zoom lens system which includes a wide angle by specifying proper arrangement of refractive power of respective lens groups in a zoom lens system which is constituted of a 1st lens group having negative refractive power, a 2nd lens group having positive refractive power and a 3rd lens group having positive refractive power in order from an object side. SOLUTION: This zoom lens system is characterized in that at the time of zooming from an end of a short focal distance to an end of a long focal distance, the interval of the 1st lens group and the 2nd lens group is decreased and the interval of the 2nd lens group and the 3rd lens group is increased and the system satisfies following conditional expressions (1) to (3), (1) 0.3<fw/¾f1¾<0.65, f1<0, (2) 0.6<fw/f2<1.2, (3) 0.3<fw/f3<0.6. Provided, fw: the focal distance of an entire system at the end of the short focal distance and fi: the focal distance of the i-th lens group. COPYRIGHT: (C)2005,JPO&NCIPI
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