| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized zoom lens, having a high zoom ratio and a small front lens diameter for attaining high optical performance over the whole zoom range. SOLUTION: In the zoo lens having a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power in order from an object side to an image side, the respective lens groups are moved to perform zooming. The first lens group is moved to the image size in zooming from a wide angle end to the telephoto end, and then moved to the object side to be positioned nearer to the object side at the telephoto end than at the wide angle end, and a distance Ximg between the position at the wide angle end of the first lens group the position of the first lens group moved to the most image side, a distance Xobj between the position at the wide angle end of the first lens group and the position of the first lens group moved to the most object end and a focal distance fw at the wide angle end of the zoom lens are respectively suitably set. COPYRIGHT: (C)2009,JPO&INPIT
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