| 摘要 |
A lens system includes, in order from the subject side to the image side of thereof, a first lens group of negative refractive power, a second lends group of positive refractive power, and an image plane. The first lens group includes a first spherical lens, a second spherical lens, and a third spherical lens arranged in this order from the subject side to the image side of the lens system. The first spherical lens includes a first subject surface and a first image surface. The lens system satisfies the following formula: 8.9<D/F0<9.9, wherein, D is the distance between an apex point of the first subject surface and the image plane along the optical axis of the lens system, F0 is the effective focal length of the lens system. |
