Interesting Color Change - Thoughts?
Cool - Thanks everyone for the information. Makes perfect sense. I guess that RAW might have also helped offset the difference, but with all the shots I normally take that is not going to happen.
It actually took the 7D for me to discover this, because with the XTi, I never would have even bothered to try shooting at night. With my new toy, I couldn't wait to try it out at night.
My first reaction was "Oh Crud" what is this, but as usual, DPreview has the answers, and I can move on. It is so much fun learning all this.
Though you can't see it, the lights at the field were almost certainly running on 120Hz cycles, rapidly turning on and off. Interestingly, this was very visible in some of the ultra-slow-motion footage at the Vancouver Olympic Games, specifically in the aerials competition.
Your eye/brain just blends it into continuous light, but a fast shutter speed actually captures the differences between on/off intensity and the color cast of the light vs. ambient.
There's not really much you can do about it - you need to tweak each image for exposure and WB. A shutter speed slower than 1/120 or 1/60 would help, but it would probably blur the image.
Just a weekend hack...
7D, Rebel XTi, Sigma 12-24, Tamron 17-50 - 2.8, 50mm f/1.8' Canon 28-135 IS, Canon EF 70-200 f/4 IS and 430EX