| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens which has reduced number of lenses, is small-sized in spite of its wide angle of view and high variable power ratio, and has a resolution corresponding to an imaging device having 3 to 5 million pixels. SOLUTION: The zoom lens is composed of a first lens group I that is fixed in varying power and provided with a positive refractive power, a second lens group II with a negative refractive power, a diaphragm S, a third lens group III, a fourth lens group IV and a fifth lens group V each with a positive refractive power, in this order from the object side. The variable power is performed by moving at least the second, the third and the fourth lens groups II, III and IV. The second lens group II has a negative lens with a strong concave facing the image plane side, wherein the concave has an aspherical surface. COPYRIGHT: (C)2005,JPO&NCIPI
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