| 摘要 |
<p>A zoom lens includes, in order from object side, a positive first lens unit which does not move for varying magnification, a negative second lens unit which moves for varying magnification, a negative third lens unit which moves for varying magnification, and a positive fourth lens unit which does not move for varying magnification, wherein the first lens unit includes a positive lens which satisfies the following conditions: 70<νp<85; 2.31<Np+0.01×νp<2.58; and 1.6<Np<1.85, where Np is refractive index of the positive lens, andνp is Abbe constant of the positive lens, and 1.25<|fp/fna|<1.7 is satisfied, where fp is focal length of the positive lens, and fna is combined focal length of negative lenses in the first lens unit defined by the equation: fna = 1∑i = 1 n 1 fn i , where n is a number of the negative lenses in the first lens unit, and fni is focal length of the i-th negative lens.</p> |
