| 摘要 |
PROBLEM TO BE SOLVED: To provide a large-aperture zoom lens whose power variation ratio is about 3, which is constituted of three lens groups as a whole, and which is constituted by arranging the lens groups so that their powers are to be negative, positive and negative in order from an object side, thereby achieving the shortening of the entire length of an optical system, and to provide a camera using the zoom lens. SOLUTION: The zoom lens has a first lens group having negative refractive power as a whole, a second lens group having positive refractive power as a whole, a third lens group having negative refractive power as a whole in order from the object side. Variable magnification is performed by positionally moving the first lens group and the second lens group in an optical axis direction, or positionally moving the third lens group in addition to the first lens group and the second lens group. COPYRIGHT: (C)2007,JPO&INPIT
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