| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens having a variable power ratio such as about 3, made completely compact and having excellent optical characteristic. SOLUTION: The zoom lens has a 1st lens group having negative refractive power, a 2nd lens group having positive refractive power, and a 3rd lens group having positive refractive power in order from an object side, and performs variable power by changing space between the respective lens groups. The 1st lens group is constituted of one positive lens and one negative lens in order from the object side, the 2nd lens group is constituted of two positive lenses and one negative lens in order from the object side, and the 3rd lens group is constituted of one positive lens. The 3rd lens group satisfies a following conditional expression; 0.5<(R1-R2)/(R1+R2)<0.95. COPYRIGHT: (C)2006,JPO&NCIPI
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