Power of the Internet, Part MMMXXCLLVI

Question at photo.net:

Has any one else expeienced the following and if so, how did you correct? I was shooting martial arts yesterday inside against a back drop. Camera was set at ISO of 1250, aperture priority at F2.8 1/640 in Raw, no flash, used continuous lighting. I was shooting high speed (CH – 6FPS). Problem was different frames in the sequence had different white balance. One or two would be dead on and several would be much yellower. I tried both auto WB and preset. I know I can fix in Photoshop, but would like to get right in camera.

Answer, 2 hours later:

You are most likely experiencing fluctuations in the electrical cycle of the lighting. To get it right in camera you will have to set your exposures based on the 60 hertz cycle (50 hertz cycle in Europe); so you have to select Manual Exposure mode and choose 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, etc. Most people don’t realize that when using Aperture priority you get slight variations in shutter speeds; so this this should avoided when getting exact shutter speeds is critical.

Then follow the example shots and comparison histograms. Amazing.