I'm interested in this for my 600f4 (esp. if I go for a D3S |:d|) but results seem mixed. Very important to stop down, but that of course necessitates good light or high ISO (or both :eek!.
For uk pricing on all camera gear, inc. now TCs, it's worth keeping an eye on
http://www.camerapricebuster.co.uk/prod1228.html
Dave,
It's not suitable for the 600/4. I tested today again in good light with the D2x and D3. I missed too many shots with the 2x on and any sudden movement lost the focus completely. For flight shots it wouldn't focus.
I did get this image which I was happy with ( almost full frame from 20 meters ) but he had almost stopped.
I switched back to the 1.7x which will enable flight shots in good light and is a good option for the f4 lenses.
Neil