| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which is used for a small-sized digital camera or a camera incorporated in a mobile telephone, the lens being small in number of components, short in overall length length, and superior in performance. SOLUTION: A zoom lens which has two lens groups, i.e. a 1st lens group with a negative refractive index and a 2nd lens group with a positive refractive index in order from an object side or has the 1st lens group with the negative refractive index, the 2nd lens group with the positive refractive index, and a 3rd lens group with a positive refractive index in order from the object side and varies the power by moving the 2nd lens group and 3rd lens group, or a zoom lens which varies the power by moving the 1st lens group and 2nd lens group is made to meet proper conditions of the Petzval sum. COPYRIGHT: (C)2006,JPO&NCIPI
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