Patent ID: 7019912
Filing Date: 2006-03-28
Classification: G02B

Abstract:
1. A zoom lens system comprising a negative first lens group, a positive second lens group, and a positive third lens group, in this order from an object, wherein upon zooming from the short focal length extremity to the long focal length extremity, a distance between said negative first lens group and said positive second lens group decreases, and a distance between said positive second lens group and said positive third lens group increases; wherein when zooming is being performed, said negative first lens group remains stationary, and said positive second lens group and said positive third lens group are moveable along the optical axis of said zoom lens system; and wherein said zoom lens system satisfies the following conditions: wherein f f fw designates the focal length of the entire zoom lens system at the short focal length extremity; and ft designates the focal length of the entire zoom lens system at the long focal length extremity.