Patent ID: 6618558
Filing Date: 2003-09-09
Classification: G02B

Abstract:
A zoom lens system comprising a positive first lens group, and a negative second lens group, in this order from an object,wherein zooming is performed by moving said positive first lens group and said negative second lens group in an optical axis direction; wherein said positive first lens group comprises a negative first lens element, a second lens element having an aspherical surface on which the curvature becomes smaller toward the periphery thereof, and a positive third lens element, in this order from said object; wherein said negative second lens group comprises a positive fourth lens group and a negative fifth lens group, in this order from said object; and wherein said zoom lens system satisfies the following conditions: âˆ’7T/f2Gâˆ’9T/f2GNwherein fT designates the focal length of the entire zoom lens system at the long focal length extremity; f2G designates the focal length of said negative second lens group, and f2GN designates the focal length of said negative fifth lens group in said negative second lens group.