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"AF-S Teleconverters TC-14E III/ TC-17E II*/TC-20E III*

<p style="color:rgb(153,153,153);font-family:Verdana, Roboto, 'Droid Sans', sans-serif;">* Autofocus is available only with single-servo AF (AF-S) and then only when the lens is mounted on a camera that supports f/8."

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Source: http://imaging.nikon.com/lineup/lens/sin...r/spec.htm
 

 

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I can't reproduce now, because the TC20II broke at some point, but I'm pretty sure that the AF-S 300 f/4 autofocuses, albeit slowly, with the 2x. In fact I have sharp bird (not in flight) photos back from 2006.