Patent ID: 7583450

Claim:
A zoom lens which comprises, in order from an object side thereof, a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, and a fourth lens group having positive refracting power, wherein zooming from a wide-angle end to a telephoto end is implemented by changing a space between the respective lens groups; upon zooming from said wide-angle end to said telephoto end, a space between said first lens group and said second lens group grows wide, a space between said second lens group and said third lens group becomes narrow, a space between said third lens group and said fourth lens group becomes narrow, said first lens group, said third lens group, and said fourth lens group moves toward the object side only, and said second lens group moves toward the object side after moving to an image plane side; said second lens group and said fourth lens group each have at least one aspheric surface; and said second lens group has at least one negative lens made of a material that satisfies the following multiple conditions, and said fourth lens group has at least one positive lens that satisfies the following multiple conditions: n d >1.4 (3) ν d >80 (4) where n d is a d-line refractive index, and ν d is an Abbe constant.