Patent ID: 6577450
Filing Date: 2003-06-10
Classification: G02B

Abstract:
A zoom lens comprising in order from object side to image side:a first lens unit having a positive optical power, the first lens unit consisting of a positive lens element; a second lens unit having a negative optical power; a third lens unit having a positive optical power; and a fourth lens unit having a positive optical power, wherein, when zooming is carried out from a wide angle end to a telephoto end, the first lens unit and the third lens unit are moved so that, at the telephoto end, the first lens unit and the third lens unit are positioned closer to the object side than at the wide angle end, and the second lens unit is moved so that, at the telephoto end, the second lens unit is positioned closer to the image side than at the wide angle end, and wherein the zoom lens further comprises at least one diffraction optical surface.