Patent ID: 6762887
Filing Date: 2004-07-13
Classification: G02B

Abstract:
A wide-angle zoom lens comprising, in order from the object side:a first lens group having a negative refractive power; a stop; and a second lens group having a positive refractive power; wherein magnification is varied by moving the second lens group to the object side when zooming from the wide-angle end to the telephoto end; what would otherwise be a shift of the image plane with the zooming is corrected by moving the first lens group to the image side when zooming from the wide-angle end to the telephoto end; a lens in the second lens group has at least one surface that is aspherical, said lens being positioned on the image side of a lens in the second lens group having positive refractive power and a convex surface the object side; no lens element intervenes between the lens in the second lens group having positive refractive power with a convex surface on the object side and the lens in the second lens group having at least one surface that is aspherical; the first lens group comprising, in order from the object side, a first lens having negative refractive power and a concave surface on the image side, a second lens that is biconcave, and a third lens having positive refractive power with a convex surface on the object side; and the second lens group comprising, in sequential order from the object side, a fourth lens having positive refractive power and a convex surface on the object side, a fifth lens having positive refractive power and at least one surface that is aspherical, a sixth lens that is biconcave, and a seventh lens that is biconvex.