Patent ID: 7167320
Filing Date: 2007-01-23
Classification: G02B

Abstract:
1. A zoom lens, comprising: a first lens group having positive refractive power, a second lens group having negative refractive power, an aperture stop, a third lens group having positive refractive power and a fourth lens group having positive refractive power which are subsequently arranged from an object side to an image side, wherein the first lens group and the third lens group move toward the object side in accordance with a change in magnification power as the zoom lens shifts from a wide-angle position to a telephoto position, the aperture stop moves independently from the lens groups next thereto, and a following conditional formula is satisfied: where X 1 represents a total amount of a movement of the first lens group in accordance with a change in magnification power as the zoom lens shifts from the wide-angle position to the telephoto position and fT represents a focal length of an entire optical system of the zoom lens in the telephoto position.