| 摘要 |
<p>A zoom lens includes sequentially from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an aperture stop, and a third lens group having a positive refractive power. The first lens group includes a negative lens and a positive lens. The second lens group includes sequentially from the object side, a negative lens, a negative lens, and a positive lens. The third lens group includes sequentially from the object side a front group having a positive refractive power, a middle group having a negative refractive power, and a rear group having a positive refractive power. The front group is formed by a positive aspheric lens. The middle group is includes a cemented lens formed by a positive lens and a negative lens.</p> |
