| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a zoom lens by shortening the focal length of the zoom lens.SOLUTION: The zoom lens includes, sequentially from the front side: a second lens group G2 that has a movable structure, consists of three lenses, and has a fourth lens 4 and fifth lens 5 that have concave surfaces on both sides and are negative lenses and a sixth lens 6 that is a positive lens; and a third lens group G3 that consists of two aspherical lenses and has a seventh lens 7 having convex surfaces on both sides and an aspherical surface in both surfaces on the front side and an eighth lens 8 which is a negative double-sided aspherical lens of a meniscus shape having a turned strong concave surface on the rear side. At least one of the three lenses constituting the second lens group G2 includes an aspherical lens. When L21, L22 and L23 are disposed from the object side and the refractive indices of L21, L22 and L23 are respectively denoted as n21, n22 and n23, the zoom lens establishes the condition: (1) n21>1.8, n22>1.75 and n23>1.9, and (2) 0.9<n21/n23<1.1. |
