Patent ID: 7626768
Filing Date: 2009-12-01
Classification: G02B

Abstract:
1. A zoom lens comprising, sequentially from an object side thereof, a first lens elements group having a negative refraction power as a whole, a second lens elements group having a positive refraction power as a whole, and a third lens element group having a negative refraction power as a whole, wherein a variable power is realized by shifting positions of the first lens elements group and the second lens elements group in a direction of an optical axis thereof, or by shifting, in addition to the positions of the first lens elements group and the second lens elements group, a position of the third lens element group in a direction of an optical axis thereof, wherein the first lens elements group is made up by disposing, sequentially from an object side thereof, a first lens element which is a negative lens, which has a negative refraction power, a second lens element which is a positive lens, which has a positive refraction power, and a third lens element which is a negative lens, and wherein the zoom lens satisfies the following conditional expression (1) with respect to a power of the first lens elements group, the following conditional expression (2) with respect to a size of the whole lens system, and the following conditional expression (3) with respect to a power of the third lens element group, the following conditional expression (4) with respect to a power of the second lens element, the following conditional expression (5) with respect to dispersion properties that are distributed to each lens element of the first lens elements group, and the following conditional expression (6) with respect to a refractive index of the second lens element: where: f f f TL f υ υ υ n