Patent ID: 7471459
Filing Date: 2008-12-30
Classification: G02B

Abstract:
1. A three-unit zoom lens system comprising, in order from an object side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive or negative refractive power, wherein a space between the first lens unit and the second lens unit changes during magnification change, a space between the second lens unit and the third lens unit changes during a focusing operation, the space between the first lens unit and the second lens unit is smaller in a telephoto end than in a wide-angle end, the second lens unit and the third lens unit move toward the only object side during the magnification change from the wide-angle end to the telephoto end, the second lens unit includes two or three lens elements in total, the two or three lens elements constitute a single cemented lens component, the cemented lens component includes a positive lens element and a negative lens element, all the lens elements in the second lens unit are included in the single cemented lens component, the third lens unit includes one lens element in total, and the following condition (1A) is satisfied, wherein D ce is a thickness of the cemented lens component of the second lens unit along an optical axis, and D 123G is a sum of thicknesses of the lens units along the optical axis.