Patent ID: 7400453
Filing Date: 2008-07-15
Classification: G02B

Abstract:
1. A zoom lens comprising: in order from an object side of the zoom lens, a first group having a positive refractive power, the first group having a three-group four-lens configuration in which a cemented lens of one negative lens and one positive lens, and two positive single-lenses are arranged in this order from the object side; a second group having a negative refractive power, the second group having a three-group four-lens configuration in which two single-lenses each having a negative refractive power with a strong concave surface on an image side thereof, and a cemented lens of one double-concave lens and one positive lens are arranged in this order from the object side; an aperture stop; a third group having a positive refractive power; and a fourth group having a positive refractive power; wherein when zooming from a wide-angle end to a telephoto end is performed, the first group and the third group are fixed, and the second group is moved to the image side thereof along an optical axis so as to perform the zooming, while the fourth group is moved along the optical axis so as to compensate a fluctuation of an imaging position caused by the zooming and perform focusing, and the zoom lens satisfies conditions: wherein M f ft designates a focal length of the zoom lens in the telephoto end; and f