http://www.nikonchat.com/af-nikkor-50mm-lens/
I bought a Nikkor AF 50mm f/1.8D lens. The "AF" stands for auto focus, but my D60 will not auto focus. Why?
The instructions say you can autofocus with Nikon AF cameras except F3AF. What the hell does that mean?
Everyone above gave a correct answer, but here is a brief explanation: Before Intoduction of offers entry-level Nikon (D40, D40, D60), the company designed most of their lenses to operate outside the autofocus motor built into the camera bodies (this is referred to simply as AF). A protruding screw mounting body "lead" the target. The Nikon D40 digital was the first body that lacks a motor body. In contrast, performance AF is only possible with lenses with an internal motor. AF-I (inner-AF) and AF-S (silent auto focus) lenses to meet this requirement.
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