Greetings. I am in the market for a teleconverter (TC-20E II) to use with my D300 and various Nikon lenses, 70-200mm f2.8 VR, 70-300mm f4.5-5.6 VR and if I get it 2nd hand a Nikon AF Nikkor 300mm f/4 IF-ED. I am of the understanding however that using a teleconverter will render ineffective the auto focus on a lens. I am wondering if my understanding is correct? Thanks in advance. Shootme...

http://forums.photographyreview.com/showthread.php?t=43901

You need to buy a Nikon brand (although a few Kenkos do this) teleconverter that has autofocus capability in order to be able to autofocus. Just remember that the TC will make your autofocus slower and you'll lose two stops of light (forget anything slower than f/4).