| 摘要 |
A compact two-group zoom lens that corrects aberrations in the visible and the near infrared regions and that provides a comparatively high zoom ratio includes, in order from the object side, a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes, in order from the object side, first and second negative meniscus lens elements having convex surfaces on the object side, a biconcave lens element, and a positive lens element. The second lens group includes, in order from the object side, a positive lens component which may be a lens element, a negative/positive doublet component, and a negative lens component which may be a lens element. Aspheric lens surfaces are disclosed. Certain conditions are satisfied to control aberrations in both the visible and the near infrared and to ensure a sufficient back focus distance.
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