Patent ID: 8913327
Filing Date: 2014-12-16
Classification: G02B,Y10T

Abstract:
1. A zoom lens system comprising, in order from an object side along an optical axis: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power, an aperture stop being disposed to an image side of the second lens group, upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increasing, a distance between the second lens group and the third lens group decreasing, a distance between the third lens group and the fourth lens group varying, and a distance between the fourth lens group and the fifth lens group varying, and the following conditional expressions being satisfied: where fT denotes a focal length of the zoom lens system in the telephoto end state, f 1 denotes a focal length of the first lens group, φW denotes the maximum diameter of the aperture stop in the wide-angle end state, φT denotes the maximum diameter of the aperture stop in the telephoto end state, and φM 5 denotes the maximum diameter of the aperture stop in an intermediate focal length state, in which the intermediate focal length of the zoom lens system is five times or more and eight times of fW or less when fW denotes a focal length of the zoom lens system in the wide-angle end state.