Leszek Vogt , Dec 28, 2012; 02:21 a.m.
Although I currently don't do any sports, I've done my share while in HS. The daytime game will be completely different game (pun intended) than murky lights (often uneven through the court) of the interior.
What you need is a combination of quality optics like "L" type and camera that can deal with low lights = high ISO's. These parameters get proper results, but also at a cost....substancial cost.
The only camera that can handle that + decent FPS speed rate, would be 5DIII. Much depends what level of quality you desire. Also the camera has pretty decent AF. Some of this would depend how far will you be from action. For nearby I'd get 85mm F1.8 or 1.4 (also expensive and F1.2 version even more). For all around lens with some reach the 70-200/2.8 would work. For better reach, funds permitting, 300/2.8....and 24-70/2.8 for everything in between. If the zoom gives you good coverage and it can handle low lights....then you probably could skip the 85mm option. I'm strictly speaking of FF.
Using smaller sensor camera like 7D or 6D can save you some cash, but the glass still applies. There are several primes in the neighborhood of F1.8 or 2.0, but none of them are inexpensive.
You could jump into the Canon EOS part of the forum and they may put a somewhat different tonality on this subject.
There are several pluses on the Nikon side, though you would need to sell your equipment and pretty much start over. Anyhoo, something to mull over. Good luck.