Patent ID: 9523843
Filing Date: 2016-12-20
CPC Classification: G02B,Y10T

Claim Text:
1. A zoom lens comprising, in order from an object along an optical axis: a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power, upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increasing, and a distance between the second lens group and third lens group decreasing, the first lens group including a positive lens A that satisfies the following conditional expression: where νdA denotes an Abbe number at d-line of a material of the positive lens A in the first lens group, and the following conditional expressions being satisfied: where fw denotes a focal length of the zoom lens in the wide-angle end state, f1 denotes a focal length of the first lens group, and Δ1 denotes a moving amount of the first lens group with respect to an image plane from the wide-angle end state to the telephoto end state, wherein the first lens group includes a positive lens B that satisfies the following conditional expression: where ndB denotes a refractive index of a material of the positive lens B in the first lens group, and the following conditional expression is satisfied: where φ1B denotes an effective diameter of the positive lens B in the first lens group.