| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact and high-performance zoom lens system by composing the system of a positive 1st lens group and a negative 2nd lens group in order from the side of an object and satisfying specified conditions. SOLUTION: A positive 1st lens group 11 and a negative 2nd lens group 12 are arranged in order from the object side. Then, the zoom lens system is constituted for zooming while changing the interval of the respective 1st and 2nd lens groups 11 and 12. In this case, the conditions of 1.4<fw/f1 G<1.7 and 0.85<Σd1 G/fw<1.1 are satisfied. In these inequalities, fw expresses the focal distance of a short focal distance end, f1 G expresses the focal distance of the positive 1st lens group,Σd1 G expresses the thickness of the 1st lens group. By satisfying these conditions, concerning the power and thickness of the positive 1st lens group 11, the moving amount of the 1st lens group 11 can be suppressed and made compact, and the aberration of the positive 1st lens group 11 can be appropriately suppressed.
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