| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-group zoom lens composed of few lenses and having excellent performance by appropriately arranging the configuration of each lens group though it is compact and has high variable power and a wide viewing angle. SOLUTION: The zoom lens has a 1st lens group G1 having positive refractive power, a 2nd lens group G2 having positive refractive power and a 3rd lens group G3 having negative refractive power in order from an object side. In the case of varying power from a wide angle end to a telephoto end, the respective lens groups are moved to an object side so that space between the 1st lens group G1 and the 2nd lens group G2 is increased from the wide angle end toward the vicinity of a middle focal distance, and then it is decreased toward the telephoto end, and space between the 2nd lens group G2 and the 3rd lens group G3 is decreased. The three-group zoom lens has a variable power ratio larger than 2, and the 1st lens group G1 is constituted of a single lens turning its concave surface to the object side and having positive refractive power. COPYRIGHT: (C)2004,JPO
|
