| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens whose entire optical system is compact, and which has a high zoom ratio, and can yield high optical performance all over the zoom range. SOLUTION: The zoom lens includes, in order from an object side to an image side: first, second and third lens groups respectively having positive, negative and positive power; and a rear group including one or more lens groups. Space between the first and second lens groups increases, space between the second and third lens groups decreases, and space between the third lens group and the rear group changes, at a telephoto end in comparison with a wide angle end. The first lens group has two positive lenses and one negative lens; and the second lens group has a negative lens and a positive lens. The Abbe numberν1p of a material of the positive lens having the largest Abbe number of material out of the positive lenses constituting the first lens group, the refractive index N2p and Abbe numberν2p of a material of one positive lens of the second lens group, the focal length f1 of the first lens group, and the focal length f1p of the positive lens having the largest Abbe number of a material out of the positive lenses constituting the first lens group are each set to be appropriate. COPYRIGHT: (C)2011,JPO&INPIT |
