| 摘要 |
PROBLEM TO BE SOLVED: To realize a high performance/ wide angle zoom lens which realizes resolution matching with an imaging device of 3 million to 6 million pixels and has a half field angle of 38°or larger at the wide angle end though it is compact. SOLUTION: The zoom lens is composed of a first group I having a negative focal length, a second group II having a positive focal length and a third group III having a positive focal length which are successively arranged in the order from an object side, and a diaphragm S which moves together with the second group and is located at the object side of the second group. The second group monotonically moves from the image side to the object side and the first group so moves to correct a variation in the position of image plane accompanying a power variation in power variation from the short focal length end to the long focal length end. The first group has, successively from the object side, at least one of negative meniscus lenses 1-1 and 1-2 with the concave face directed to the image side, a biconvex lens 1-3, and a biconcave lens 1-4 which is joined to the biconvex lens. COPYRIGHT: (C)2004,JPO&NCIPI
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