Patent ID: 7835084
Filing Date: 2010-11-16
Classification: G02B

Abstract:
1. A zoom lens system comprising: a first lens unit having positive optical power; a second lens unit having negative optical power, the second lens unit being configured to move when the zoom lens system performs zooming; a third lens unit having positive optical power; and a fourth lens unit having positive optical power, the fourth lens unit being configured to move when the zoom lens system performs zooming, wherein the first, second, third, and fourth lens units are arranged in that order from an object side towards an image side, wherein the second lens unit consists of a negative lens element, a negative lens element, a negative lens element, and a positive lens element that are arranged in that order from the object side towards the image side, wherein the following conditions are satisfied: where f wherein the following conditions are satisfied: where ft denotes a focal length of the entire system at a telephoto end.