Patent ID: 7791818
Filing Date: 2010-09-07
Classification: G02B

Abstract:
1. A zoom lens system comprising: a first lens group including at least one reflective optical member changing the optical path of an incident light ray, and having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, wherein the first, second, third and fourth lens groups are sequentially arranged from the object side, during a magnification change from a wide-angle position to a telephoto position, the first lens group and the third lens group are not moved, the second lens group is moved from the object side towards an image side, and the fourth lens group is linearly moved from the image side towards the object side; the fourth lens group comprises a lens having negative refractive power, a lens having first positive refractive power, and a lens having second positive refractive power, wherein the lens are sequentially arranged from the object side; the fourth lens group is configured so that the lens having negative refractive power and the lens having first positive refractive power are cemented as a doublet lens; and the zoom lens system satisfies the following condition, where R R