Patent ID: 8681432
Filing Date: 2014-03-25
Classification: G02B

Abstract:
1. A zoom lens comprising, in order from an object side to an image side and arranged along an optical axis thereof, 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, all of the lens units being moved during zooming from a wide-angle end to a telephoto end, wherein an aperture stop is arranged on the image side of the third lens unit, wherein the third lens unit includes at least three positive lenses and one negative lens, and wherein the zoom lens satisfies the following conditions: where T23 denotes a distance from a lens surface closest to the image side in the second lens unit to a lens surface closest to the object side in the third lens unit when the zoom lens is at the telephoto end, fT denotes a focal length of the entire zoom lens at the telephoto end, and f1, f2, and f3 denote focal lengths of the first, second, and third lens units, respectively.