Patent ID: 6982834

Claim:
A zoom lens comprising, arranged on an optical axis in order from the object side as follows: a first lens group of negative refractive power; a second lens group of positive refractive power and that includes a stop for controlling the amount of light that passes through the zoom lens; and a third lens group of positive refractive power; wherein the first and the second lens groups are moved so that the first and second lens groups become closer together during zooming from the wide-angle end to the telephoto end; the second and third lens groups are moved relatively so that the second and third lens groups become farther apart during zooming from the wide-angle end to the telephoto end; the third lens group is moved toward the object side during focusing from infinity to a close focus; the first lens group includes, arranged on the optical axis in order from the object side, a first lens element of negative refractive power and a second lens element of positive refractive power, and at least one of said first lens element and said second lens element includes at least one aspheric lens surface; the shape of said at least one aspheric lens surface is given by an aspheric lens equation that includes at least one non-zero coefficient of an even power of Y, and at least one non-zero coefficient of an odd power of Y, where Y is the distance of a point on the aspheric lens surface from the optical axis; and the following conditions are satisfied: 36.0<θ w <41.0 ν d1 −ν d2 >20.5 where θ w is the half-field angle of the zoom lens at the wide-angle end, ν d1 is the Abbe number at the d-line of said first lens element, and ν d2 is the Abbe number at the d-line of said second lens element.