Actually I don't think I've provided much insight at all. None of what I say are backed up by reasons; like I say in the first post, that's so you can go learn for yourself, which is the best way to learn.
Originally posted by rochkoh
I had a lot of problems focusing with my F80, 80-200/2.8 with 2X-TC, trying to track them wakeboarders while they're being dragged along... ...Problem was, i could not get a lock on the wakeboarder in action.
Ah. But you see, that's dangerous. 80-200 AF-D or AF-S? If it's AF-D, then your results are entirely expected. Don't then go and write off the camera's autofocus, and dynamic autofocus, because it's not what's causing the problem. There's a reason why Nikon doesn't sell 2x converters which maintain AF for screwdriver driven lenses - it doesn't work. Plenty of third party manufacturers sell them, and they do move the focusing elements, but at a snails pace and with such lack of pace that yes indeed you are better off shooting manually half the time.
If it's an AF-S combi you were using, then really assuming decent sunlight, the camera shouldn't have a problem either. Aside from the light loss resulting in two stops of light less reaching the AF sensor, the combi should function everybit as well as an unencumbered AF lens.
The wakerboarders were either moving right to left, or left to right. And i had to move my camera in tandem with the movement of the subject - panning technique. Was i doing anything wrongly?
No, nothing wrong. Just not relevant to the viability of dynamic AF. Being able to track a subject requires your own practice, yes... hand eye co-ordination. It's necessary whether you're manual focusing, autofocusing with one point or with dynamic AF. So I don't see how it's relevant in a discussion of whether dynamic AF works. In fact, you need the most practice with MF, because in addition to following the subject, you also need to be able to focus at the same time... massive amounts of hand eye co-ordination needed. Which is why I said I found it curious you could MF and follow, but not AF and follow.
And so since my camera was going berserk with all that focusing, i switched to manual mode, tracked the subject - and got most of my shots. 
Good for you, at least shows you're thinking. At the moment I'd be inclined to blame the converter.
True. But in my case, it did. Was the subject too small? Was my equipment at fault? Was i using the wrong technique?
Subject too small - quite possibly. Equipment at fault - see above about converters. Wrong technique - I can't tell without observing you, but it doesn't sound like you had a problem.
What kinda operator errors were you talking about?
Missing the subject with the AF point. No AF system in the world can focusing on a subject that it isn't pointed at. Mind you the Nikon system does a good job of temporarily not reaquiring focus should this happen. In fact, this is the main reason to use dynamic AF which increases this potential, when you can spare the raw speed of a single AF point, and are not shooting subjects where having five instead of one point are a problem.
