Patent ID: 7492527

Claim:
A three-group zoom lens comprising, in order from an object side: a first lens group having a negative refractive power; a second lens group having a positive refractive power; and a third lens group having a positive refractive power, wherein the three-group zoom lens varies power by changing spacing among the respective lens groups, wherein the first lens group comprises: a first lens having a negative refractive power; and a second lens that is formed from a plastic material, has a biconvex shape, has at least one surface of an aspherical shape and has a positive refractive power, wherein the second lens group comprises: a cemented lens formed from a third lens having a positive refractive power and a fourth lens having a negative refractive power; and a fifth lens having a meniscus shape whose convex surface is oriented to the object side, wherein the third lens group comprises a sixth lens having a positive refractive power, and wherein conditional expressions (1) through (3) provided below are fulfilled: 3.2 <fg 2 /fw (1) 26<ν 1 −ν 2 <30 (2) D 1 /fw< 0.75 (3), where fg 2 : a focal length of the second lens fw: a focal length of the three-group zoom lens achieved at a wide-angle end ν 1 : Abbe number of the first lens ν 2 : Abbe number of the second lens D 1 : Axial distance from a lens surface most closely positioned to the object side to a lens surface most closely positioned to an image side in the first lens group.