| 摘要 |
A wide-angle fast lens system includes a front lens group having a negative power, a diaphragm and a rear lens group having a positive power. The front lens group consists of a first sub-lens group and a second sub-lens group having a negative power. The lens system satisfies the following relationships: -0.6<f/fF<-0.2, 6.0< SIGMA dF+S/f<12.0, f/|f1a|<0.07, and 0.4<haF/haL<0.65, wherein "f" represents the focal length of the whole lens system, "fF" represents the focal length of the front lens group, " SIGMA dF+S" represents the sum of the thickness of the front lens group and the distance between the front and rear lens groups, "f1a" represents the focal length of the first sub-lens group, "haF" represents the height of the paraxial rays incident on the first surface of the first sub-lens group, and "haL" represents the height of the paraxial rays incident on the last surface of the first sub-lens group. |
