| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which gets along with a small number of constituent lenses and is compact while maintaining the zoom ratio of three times or more and the excellent optical performance. SOLUTION: The zoom lens has a first lens group having negative refractive power, a second lens group having positive refractive power and a third lens group having positive refractive power in order from the object side to the image side, wherein spaces between respective groups are changed upon zooming. The first lens group L1 is composed of one sheet of negative lens and one sheet of positive lens, the second lens group L2 is composed of a 2a lens group L2a having one sheet of positive lens/one sheet of negative lens and a 2b lens group L2b which is arranged on the image side of the 2a lens group and has at least one sheet of positive lens, and the third lens group is composed of at least one sheet of positive lens. COPYRIGHT: (C)2006,JPO&NCIPI
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