Patent ID: 6785055
Filing Date: 2004-08-31
Classification: G02B

Abstract:
A zoom lens system comprising, from an enlargement side:a first lens unit having a negative optical power; a second lens unit having a positive optical power and disposed on an image side of the first lens unit with a first variable distance secured in between; a third lens unit having a positive optical power and disposed on an image side of the second lens unit with a second variable distance secured in between; a fourth lens unit having a negative optical power and disposed on an image side of the third lens unit with a third variable distance secured in between, the fourth lens unit including an aperture stop; a fifth lens unit having a positive or negative optical power and disposed on an image side of the fourth lens unit with a fourth variable distance secured in between; and a sixth lens unit having a positive optical power and disposed on an image side of the fifth lens unit with a fifth variable distance secured in between, wherein zooming is achieved by varying the first to fifth variable distances, wherein the third and fifth lens units move from the enlargement side to a reduction side during zooming from a telephoto end to a wide-angle end, and wherein the zoom lens system is substantially telecentric toward the reduction side.