| 主权项 |
1. A zoom lens, comprising:
a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having positive refractive power, wherein the second lens group is disposed between the first lens group and the third lens group, wherein the second lens group comprises at least one aspheric glass lens, wherein the first lens group comprises a first lens, a second lens and a third lens arranged sequentially, the first lens has negative refractive power, the second lens has negative refractive power, and the third lens has positive refractive power, wherein the second lens group comprises a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged sequentially, the fourth lens has positive refractive power, the fifth lens has positive refractive power, the sixth lens has negative refractive power, and the seventh lens has positive refractive power, wherein the third lens is disposed between the second lens and the fourth lens, wherein the third lens group comprises an eighth lens having positive refractive power, wherein the second lens comprises a first surface and a second surface, the first surface faces to the first lens and the second surface faces to the third lens, a focal length of the first surface is f121, a focal length of the second surface is f122, and 1.1≦f121/f122≦1.3, wherein an effective thickness of the center of the second lens is Teff, and 10≦|f121/Teff|≦11. |
