Patent ID: 6606202
Filing Date: 2003-08-12
Classification: G02B

Abstract:
A zoom lens system comprising, in order from an object side:a first lens unit of positive refractive power that doesn't move along an optical axis for zooming; a second lens unit of negative refractive power that moves along the optical axis for zooming; a third lens unit of positive refractive power that doesn't move along the optical axis for zooming, said third lens unit including, in order from the object side, a first lens subunit of positive refractive power consisting of one or two positive lens element facing to the object side a convex surface of refractive power that is stronger at the object side than an image side, and a second lens subunit including a cemented lens coupling a concave surface of a negative lens element of refractive power that is stronger at the image side than at the object side, with a convex surface of a positive lens element of refractive power that is stronger at the object side than at the image side; and a fourth lens unit of positive refractive power.