Patent ID: 7492525

Claim:
A zoom lens for photography, comprising, in order from an object: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; a fourth lens group having a positive refracting power; and a fifth lens group arranged closer to an image than a unit of the first to fourth lens groups, said fifth lens group having a positive power, wherein the zoom lens is configured such that when zooming from a short focal point end to a long focal point end, the second lens group moves toward the third lens group and the fourth lens group moves toward the third lens group, and wherein when a distance from a first lens surface to an imaging plane at the long focal point end is Σd, a focal length of the zoom lens at the short focal point end is fw, and a focal length of the zoom lens at the long focal point end is ft, the following conditional formula is satisfied: 1.45 <Σd /( ft−fw )<2.2.