Patent ID: 7006300
Filing Date: 2006-02-28
Classification: G02B

Abstract:
1. A zoom lens comprising, arranged along an optical axis in order from the object side: a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having positive refractive power; wherein the first lens group and the second lens groups move along the optical axis during zooming; the first lens group includes, arranged along the optical axis in order from the object side, a first lens component having negative refractive power and a second lens component that consists of a lens element having two spherical surfaces, having positive power, and having a meniscus shape with the convex surface on the object side; the second lens group includes, arranged along the optical axis in order from the object side, a third lens component that consists of a lens element made of plastic, having a convex surface near the optical axis on each side, and being aspheric on at least one side, and a fourth lens component that consists of, arranged along the optical axis, two lens elements, each of which has a spherical surface on each side; the third lens group consists of a fifth lens component with a convex surface on its image side; at least one of said first lens component and said fifth lens component is made of plastic; and the following conditions are satisfied: where ft is the focal length of the zoom lens at the telephoto end, fw is the focal length of the zoom lens at the wide-angle end, MTLw is the distance from the most object-side lens surface of the zoom lens to the image plane at the wide-angle end when focused on an object at infinity, φ1 is the optical power of the first lens group, φ3 is the optical power of the third lens group, and V