| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-performance zoom lens miniaturized to such an extent as a single focus standard lens, constituted of a small number of lenses, having a variable power ratio of about 2.9 and easily manufactured. SOLUTION: The zoom lens has a 1st negative lens group G1 and a 2nd positive lens group G2 in order from an object side, and performs variable power by changing space Ds between the 1st lens group G1 and the 2nd lens group G2. The 1st lens group G1 has at least a negative lens L<SB>1</SB>and a positive lens L<SB>1p</SB>in order from the object side, and the 2nd lens group G2 has a front lens group G<SB>2-1</SB>having a positive lens L<SB>a</SB>and a doublet comprising a positive lens L<SB>ap</SB>and a negative lens L<SB>an</SB>and having positive refractive power, and a rear lens group G<SB>2-2</SB>having a doublet comprising a negative lens L<SB>bn</SB>and a positive lens L<SB>bp</SB>and having positive refractive power in order from the object side. Furthermore, the 2nd lens group G2 has an aperture diaphragm S deciding an F value in the front lens group G<SB>2-1</SB>or in the vicinity of the object side of the front lens group G<SB>2-1</SB>, and the zoom lens satisfies a predetermined conditional expression. COPYRIGHT: (C)2006,JPO&NCIPI
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