I took some time tonight to experiment and illustrate why stadium lighting fixtures (mercury vapor, fluorescent, etc.) often yield unexpected and hard to control shifts from frame to frame. See my hidden gallery here: http://www.sportsshooter.com/guyrhodes/wbtests/
A large copy of the test comparison image is at: http://www.guyrhodes.com/photo/wb_experiment_large.jpg
Pull that image open in another window if you'd like, then read my results:
In the following comparison between white balance methods, I shot the back of white sync-slate with color chips on the sticks under a typical fluorescent light fixture. I chose to use 1/500th of a second shutter speed, the ideal "bare minimum" that I'd use for fast action sports that might be shot under discharge lighting (football, basketball, etc.).
I shot a burst of six images at eight frames per second using a Canon 1D MarkII.
As you can see in rows one and two, the color is all over the place throughout the burst with both fluorscent (row 1) and tungsten (row 2) white balances.
As someone suggested in a separate thread, I slowed down to 1/30th of a second (slower than the 60Hz cycling of the light), and performed a custom white balance off the white portion of the sync slate. Running the shutter back up to 1/500th and shooting another burst (row 3) revealed the same color shifting anomaly, because again, we're still locked into one white balance (albeit a custom one) as the color of the lights goes up and down, up and down. Custom white balancing will NOT solve color shifting under discharge lights at high shutter speeds, even if you custom white balance at a speed slower than the cycle, as illustrated here.
I had to eat my own words when I tried auto white balance (row 4) as my next test. Colors still shifted through the burst, despite my thoughts that the camera would analyze each frame as it was shot.
The only way I was able to get consistent color in a burst under the fluorescent light (row 5) was to slow down the shutter speed to equal that of the cycling, which in the United States, would mean setting the camera to 1/60th or slower. This would be fine for shooting features in an office, but would hardly be adequate for available light action sports.
This experiment serves as further fuel for my loathing of discharge lighting fixtures, and the reason why I'll drag strobes to every indoor (and sometimes outdoor) sport I shoot where I know discharge light fixtures will be present.
As a last point of reference for those still hazy on 60Hz color cycling, legally download the music video by Nas featuring Puff Daddy called "Hate Me Now." The beginning of the video features several explosions on a street captured at night with a high speed film camera. You can clearly see the sodium and fluorescent lights in the background pulsing, revealed only by the extremely slow motion film.