Patent ID: 6556356
Filing Date: 2003-04-29
Classification: G02B

Abstract:
A zoom lens system comprising, in order from an object:a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power; each lens group being moved to the object side such that when the state of lens group positions of the zoom lens system is changed from a wide-angle end state to a telephoto end state, the separation between the first lens group and the second lens group increases, the separation between the second lens group and the third lens group decreases, and the separation between the third lens group and the fourth lens group decreases; an aperture stop being arranged in the vicinity of the third lens group; and the fourth lens group being composed of four lens elements arranged, in order from the object; a first positive lens element; a first negative lens element; a second positive lens element; and a second negative lens element.