Patent ID: 8379319

Claim:
A zoom lens 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, a distance between the first lens group and the second lens group being changed and a distance between the second lens group and the third lens group being changed upon zooming from a wide-angle end state to a telephoto end state, the first lens group comprising three lenses, the second lens group comprising three lenses, the third lens group comprising three lenses, and the following conditional expressions being satisfied: 2.70 <TLt /( fw×ft ) 1/2 <3.70 0.05 <D 1 /ft< 0.29 1.00 <D 1 /fw< 1.50 where, TLt denotes a total length of the zoom lens in the telephoto end state, fw denotes a focal length of the zoom lens in the wide-angle end state, ft denotes a focal length of the zoom lens in the telephoto end state, and D 1 denotes a thickness of the first lens group on the optical axis.