Patent ID: 7286298

Claim:
A zoom lens comprising: a first lens group having a positive refraction power; a second lens group having a negative refraction power; a third lens group having a positive refraction power; and a fourth lens group having a positive refraction power, wherein said first, second, third and fourth lens groups are arranged sequentially from an object side toward an image side, wherein a magnification is changed from a wide angle end of the zoom lens to a telephoto end thereof, and vice versa, by varying each distance between each pair of said first to said fourth lens groups, and wherein said first lens group comprises only two pieces of lens consisting of a positive lens and a negative lens, said third lens group comprises at least a positive lens and a negative lens arranged sequentially from the object side, at least said positive lens of said third lens group is a spherical lens, and a lens of said third lens group which is located closest to the image side is a lens having an aspherical surface on at least one surface thereof.