| 摘要 |
A zoom lens comprises in order from an object side,
a first lens unit having a positive refractive power,a second lens unit having a negative refractive power, anda third lens unit having a positive refractive power, andthe third unit having a positive refractive power comprises in order from the object side,a first lens component having a positive refractive power, anda second lens component having a negative refractive power in which, a lens having a positive refractive power and a lens having a negative refractive power are cemented, andthe zoom lens satisfies the following conditional expressions (1), (2), and (3)
1.4<|f3—2p/f3—2n|<2.6 (1)nd3—2p−nd3—2n≧0 (2)nd3—2n≧1.8 (3). |
| 主权项 |
1. A zoom lens comprising in order from an object side:
a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a third lens unit having a positive refractive power, wherein the third lens unit having a positive refractive power comprises in order from the object side, a first lens component having a positive refractive power, and a second lens component having a negative refractive power in which, a lens having a positive refractive power and a lens having a negative refractive power are cemented, and the zoom lens satisfies the following conditional expressions (1), (2), and (3)
1.4<|f3—2p/f3—2n|<2.6 (1)nd3—2p−nd3—2n≧0 (2)nd3—2n≧1.8 (3) where, f3—2p denotes a focal length of the lens having a positive refractive power, in the second lens component having a negative refractive power, in the third lens unit having a positive refractive power, f3—2n denotes a focal length of the lens having a negative refractive power, in the second lens component having a negative refractive power, in the third lens unit having a positive refractive power, nd3—2p denotes a refractive index for a d-line of the lens having a positive refractive power, in the second lens component having a negative refractive power, in the third lens unit having a positive refractive power, and nd3—2n denotes a refractive index for the d-line of the lens having a negative refractive power, in the second lens component having a negative refractive power, in the third lens unit having a positive refractive power. |
