Nikon 500F4 AFSII with TC20E autofocus.

<p>Can anyone tell me if this combo actually will or will not autofocus. I know Nikon says no but they also say no to the TC17E which I find will autofocus quite well in good light, not so hot but not bad in poor light. Looking for actual experiences.</p>

<p>Don, what body are you talking about doing this on? It almost surely depends on the body.<br>

I've don't have a 500/4 AFSII, but I've used AF with a D3x and a D2x on a 300/4 + TC20E on high contrast subjects in bright light. (The results aren't anything to write home about, but it does work). But my old D100 just hunts and hunts with the same combo, no matter how bright the subject.</p>

<p>Nikon's AF system is designed to work with lenses that are at least f5.6 wide open. When you add a 2X TC onto an f4 (500mm) lens, it becomes max f8 and AF will be unreliable. I have used that combo and AF is iffy under bright light. Under dim light it will hunt seriously.</p>

<p>Thanks for the info Shun, all I need to know. It confirms what I was hoping was the case.</p>