Patent ID: 8130451
Filing Date: 2012-03-06
Classification: G02B

Abstract:
1. A zoom lens system, comprising, in order from an object side to an image side: a first lens unit which has a positive optical power and does not move for zooming; a second lens unit having a negative optical power; a third lens unit having a positive optical power; a fourth lens unit having a negative optical power; and a fifth lens unit which has a positive optical power and moves along a locus convex to the object side for zooming, wherein the second lens unit has a largest ratio of an imaging magnification at a telephoto end to an imaging magnification at a wide-angle end among lens units included in the zoom lens system; and wherein the following condition is satisfied where max|β 4 ×β 5 | denotes a maximum value of a product of a lateral magnification of the fourth lens unit and a lateral magnification of the fifth lens unit in zooming from the wide-angle end to the telephoto end, and min|β 4 ×β 5 | denotes a minimum value of a product of the lateral magnification of the fourth lens unit and the lateral magnification of the fifth lens unit in zooming from the wide-angle end to the telephoto end.