| 摘要 |
A rear conversion lens, for attachment to the rear of a main lens, is formed of only three lens groups of positive, negative, and positive refractive power, respectively, in order from the object side. The first lens group is formed of a first lens element of negative meniscus shape with its convex surface on the object side, and a second lens element of positive refractive power that is biconvex. The second lens group is formed of a third lens element that is biconcave, and a fourth lens element of negative refractive power with a concave surface on the object side. The third lens group is formed of a fifth lens element that is biconvex, and a sixth lens element of negative meniscus shape with its convex surface on the image side. Various conditions are satisfied to facilitate ease of manufacture and to assure good optical performance.
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