Patent ID: 7289275

Claim:
A zoom lens system comprising, in order from an object side to an image side: a first lens unit having a negative optical power, wherein the first lens unit includes only, in order from the object side to the image side, a first negative lens element and a second positive lens element as the lens elements; a second lens unit having a positive optical power, wherein the second lens unit includes only, in order from the object side to the image side, a third positive lens element, a fourth positive lens element, a fifth negative lens element and a sixth positive lens element as the lens elements; and a third lens unit having a positive optical power, wherein an interval between the first and second lens units, and an interval between the second and third lens units change during zooming, wherein the third lens unit moves to the image side during the zooming from a wide-angle end to a telephoto end; and wherein a focal length of the third lens unit is f 3 , a focal length of the whole system in the wide-angle end is fW, and the condition 4.0<f 3 /fW<5.0 is satisfied.