Patent ID: 7227699
Filing Date: 2007-06-05
Classification: G02B

Abstract:
1. A zoom lens system comprising: a first lens unit having positive refractive power; a second lens unit having negative refractive power; a third lens unit having positive refractive power; and a fourth lens unit having positive refractive power, wherein the first to fourth lens units are provided in order from the object side to the image side, wherein the third lens unit includes a first lens sub-unit having negative refractive power and a second lens sub-unit having positive refractive power, the first and second lens sub-units provided in order from the object side to the image side, wherein, during zooming, the second lens unit and the fourth lens unit are moved along an optical axis, wherein the second lens sub-unit is moved in a direction substantially orthogonal to the optical axis so as to displace the image in a direction orthogonal to the optical axis, and wherein, where f1 represents the focal length of the first lens unit, f3 a represents the focal length of the first lens sub-unit, and f3 b represents the focal length of the second lens sub-unit.