| 摘要 |
A single focus telescopic lens includes, in order from the object side: a diaphragm stop; and first and second lens components, each lens component being of positive refractive power and each having a convex surface on the object side near the optical axis. Each of the two lens components has two aspheric surfaces, may be a lens element, and preferably is made of plastic. The single focus telescopic lens may include no other lens elements and the diaphragm stop may be on the object side of the single focus telescopic lens. A specified on-axis condition is satisfied in order to reduce aberrations and to make the single focus telescopic lens compact. Additionally, satisfying a condition related to the maximum angle of incidence of among all the image forming principal rays helps achieve the desired telescopic properties with the desired optical performance.
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