Patent ID: 6751028
Filing Date: 2004-06-15
Classification: G02B

Abstract:
A zoom lens comprising, in order from an object side to an image side,a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power, and a fourth lens unit of positive refractive power, zooming from a wide-angle end to a telephoto end being effected by moving said second lens unit toward the image side, and shifting of an image plane due to zooming being compensated for by moving said fourth lens unit, wherein said second lens unit consists of four lenses including three negative lenses and one positive lens, and at least one of said four lenses is an aspherical lens, and wherein the zoom lens satisfies the following condition: 1.2824/R25<3.20 where R24 and R25 are radii of curvature of the fourth and fifth lens surfaces, respectively, when counted from the object side, in said second lens unit.