| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens of a rear focus system which has four lens groups as a whole, performs focusing with the fourth group, is made smaller in the size over the entire part of the lens system and is wide in an angle of view. SOLUTION: The zoom lens consists of the four lens groups; the first group of positive refractive power, the second group of negative refractive power, the third group of positive refractive power, and the fourth group of positive refractive power, in order from an object side, performs variable magnification from a wide angle end toward a telephoto end by moving the second group to an image plane side, corrects a fluctuation in the image plane accompanying the variable magnification or the fluctuation in the distance of a subject by moving a part or the entire part of the fourth group, and is arranged with a glass block between the fourth group and the image plane. The respective lens groups are appropriately set. COPYRIGHT: (C)2007,JPO&INPIT
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