Patent ID: 8233223

Claim:
A telephoto lens system comprising a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power that are sequentially disposed from an object side, wherein the second lens group performs focusing, and the third lens group includes a front lens group having a negative refractive power and a back lens group having a positive refractive power, and vibration correction is performed by moving the front lens group of the third lens group in a direction perpendicular to the optical axis, wherein the first lens group includes at least three lenses having a positive refractive power, and the at least three lenses having a positive refractive power satisfy the conditions below V ( G 1)≧70, 150<φFNO<400, where V(G 1 ) denotes an Abbe number of one of the lenses having a positive refractive power included in the first lens group, φ denotes the effective diameter of the lens disposed closest to the image side among the lenses having a positive refractive power, and FNO denotes an F-Number of the overall telephoto lens system.