lright here's the list of my equipment: Nikon D3 Nikon 70-200 VR Sigma 10-20 f/4-5.6 Sigma 28-70 f/2.8 Nikon 50 f/1.8 I bought a Promaster 1.7x TC from a "local" (3 hours away) store. Well it turns out that the AF doesn't work with my D3 as all my photos are OOF with it. I am returning it and all the store can get in is Nikon TC's which I feel are overpriced. I am looking at the Kenko 1.4x Teleplus Pro 300, Kenko 2.0X Pro 300 , and Kenko 1.5x. I plan on using the TC with my 70-200 as well as my 10-20 (which makes it look somewhat like it did on my D200). My question is this. Will these TCs work with both the 70-200 and the 10-20? Which one do you prefer? Obviously the 1.4 is going to have the better IQ than the 2x but is the extra reach of the 2x worth it? I shoot sports and find my 70-200 to be too short for football and soccer. I like the price on the 1.5x but I worry about IQ with that price tag. I also wonder how fast/slow the AF is with these TCs as it seems everyone has a different opinion. To summarize MY findings: Kenko 1.4x: $200 + shipping, not as much reach but good IQ. Kenko 1.5x: $86 + shipping, haven't found much information on it. Kenko 2x: $220 + shipping, more reach would be nice but IQ (from what I've read) is not as good as 1.4x. Any help is appreciated!