| 摘要 |
A zoom lens includes, in order from object side to image side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. During zooming, the first lens unit and the second lens unit move so that the distance between the first lens unit and the second lens unit changes. The first lens unit includes at least one positive lens and at least one negative lens. The total length of the zoom lens at the wide angle end, the back focal length at the wide angle end, the focal length of the zoom lens at the telephoto end, the focal length of the first lens unit, the focal length of the second lens unit, and the refractive index of the material of the at least one positive lens included in the first lens unit are each appropriately set according to mathematical conditions. |
| 主权项 |
1. A zoom lens comprising, in order from object side to image side:
a first lens unit having a negative refractive power; and a second lens unit having a positive refractive power, wherein, during zooming, the first lens unit and the second lens unit move so that a distance between the first lens unit and the second lens unit changes, wherein the first lens unit includes at least one positive lens and at least one negative lens, and wherein the zoom lens satisfies conditional expressions
4.0<TLw/BFw<12.0,0.20<f2/ft<0.90,−1.30<f1/f2<−0.20,and1.86<Nd<3.00, where TLw is a total length of the zoom lens at a wide angle end, BFw is a back focal length at the wide angle end, ft is a focal length of the zoom lens at a telephoto end, f1 is a focal length of the first lens unit, f2 is a focal length of the second lens unit, and Nd is a refractive index of a material of the at least one positive lens included in the first lens unit. |
