| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens in which the number of component lenses is not more than 10, and various aberrations including distortion aberration at a short focus end, spherical aberration, or the like is completely corrected, and which has a variable magnification ratio of 2.5 or more. SOLUTION: In the zoom lens having at least a first lens group having positive focal length, a second lens group having negative focal length and a third lens group having positive focal length in order from an object side, a magnification is changed by moving the second and the third lens groups. The zoom lens satisfies conditional expressions; -0.65<β<SB>3T</SB><-0.4 and 1.2<(β<SB>2T</SB>/β<SB>2W</SB>)(β<SB>3W</SB>/β<SB>3T</SB>)<3.0 and also satisfies conditional expressions; 0.13<f<SB>W</SB>/f<SB>1</SB><0.22, -0.82<f<SB>W</SB>/f<SB>2</SB><-0.5 and 2.8<f<SB>1</SB>/f<SB>3</SB><3.7, and is constituted so that the variable magnification ratio showing the ratio of focal length at the short focus end and a long focus end may be≥2.5. COPYRIGHT: (C)2005,JPO&NCIPI
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