| 摘要 |
PROBLEM TO BE SOLVED: To keep high optical performance capable of varying power comparatively on a telephoto side and providing a high quality image, while having a compact configuration, in a variable power optical system. SOLUTION: The variable power optical system includes four lens groups of the first lens group G1 to the fourth lens group G4. When varying the power from the wide-angle end to the telephoto end, the first lens group G1 and the third lens group G3 are fixed and the second lens group G2 is moved to an image side, thereby varying the power and the fourth lens group G4 is moved thereby performing the correction of an image surface position associated with varying the power and focusing. The first lens group G1 includes a positive eleventh lens L11, a positive twelfth lens L12 and a negative thirteenth lens L13 in order from an object side. The fourth lens group G4 includes a positive 41st lens L41, a negative 42nd lens L42 whose convex surface faces the image side and a positive 43rd lens L43 in order from the object side. The fourth lens group G4 includes a positive lens whose at least one surface is an aspherical surface. COPYRIGHT: (C)2010,JPO&INPIT
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