Patent ID: 7215487
Filing Date: 2007-05-08
Classification: G02B

Abstract:
1. A zoom lens including a function of preventing blurring of an image comprising, arranged along an optical axis in order from the object side as follows: a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having positive refractive power; wherein said first lens group includes, arranged along the optical axis in order from the object side, a lens element having negative refractive power and a lens element having positive refractive power; said first lens group includes at least one aspheric lens surface; said second lens group includes, arranged along the optical axis in order from the object side, a lens element having positive refractive power and a lens element having negative refractive power that are joined together to form a doublet, and a lens element having a meniscus shape, and including at least one aspheric lens surface; the distance along the optical axis between said first lens group and said second lens group changes during zooming between the wide-angle end and the telephoto end; the distance along the optical axis between said second lens group and said third lens group changes during zooming between the wide-angle end and the telephoto end; said third lens group moves along the optical axis toward the object side during focusing of the zoom lens from infinity to close range; said second lens group moves orthogonally to the optical axis in order to correct for blurring of an image at an image plane on the image side of the zoom lens due to movements of the zoom lens; and the following condition is satisfied: where β2t is the image magnification of said second lens group at the telephoto end.