Mercury vapor lighting

[gardener]

I took some pictures out at the Mesquite rodeo last weekend and while the arena was well lit, the main lighting source were the big mercury vapor lights up on the building girders. The pics were more for fast action / panning camera practice than anything else and were shot as LF JPEG's with a handheld 20D and 70-200 2.8f IS lens. Even with the abundant lighting, I used "Auto" white balance simply because I couldn't figure out a better setting from the choices given on the camera menu (more practice). Still, the ISO had to be set up high (800 to 1600) to get any decent shutter speed to catch the quick little buggers doing what they do at rodeos. No particular overall color cast in the final results to worry about but if there's a better way to do it then I'm all for trying something new...
Questions:
1: With this type of lighting, was there a better white balance choice?
2. Is this an instance where doing a "custom" white balance would be better? Note that I've never done one nor thought I needed to up to this point but I know the basics of how to do it...
3. How would you have set up your camera to start with? The camera brand doesn't really matter since settings are roughly similar on most DSLR's.

Note there were ample places to stand where I could have gotten better action shots but with grandbrats and kinfolk in tow, that was pretty much out of the question for this trip as I was more or less confined to my assigned seat with them.
I will say that the rodeo people were more than nice about allowing photography with whatever you brought in and seem to be quite amicable about letting photographers stand where they might get the best view as long as it's a "public" area.
As always, thanks for any information that you may be able to provide that will make me a better photographer.
Steve W

[DEMDeepEllumMusic]

You could have set the camera on auto and shot your first shot as a white card, most 18% gray cards have a white back, then then when your in PS you set the white card to true white.

I think that there can be a problem with mercury vapor lamps in that they all do not put out the same Kelvin in their light output, as they age the output can vary but I am not positive about that.

Yes an arena like that may look bright to your eye but in reality it is quite dark to the camera especially when the action is fast. (guess you need to go to an arena that is being lit for network broadcasting to find one that is really lit up).

Anybody know how they view use of flashes? Maybe have a couple that are hooked up to wireless triggers to flood an area, but then that multiple flash could affect the performance of a cowboy or the animal. Maybe use this when the kids are out chasing sheep or maybe in bulldoging once he has the steer by the horns.

[ericf]

I've shot quite a few indoor volleyball games and have found that I have to adjust white bal. in each shot, post process. The pics seem to have three different white variations that I could almost group them into. I also use Auto WB. I've tried different settings but it didn't help. I've been told that mercury vapor and some Sodium vapor lighting go through the whole color spectrum (Temp. K) so fast and then repeat, that our eyes can not perceive it. But the camera shutter can and does. I've had shots go from slightly warm to very cool at the same game taken within sec. of each other. It never is uniform and I've come to just expect it and deal with it later.

[DEMDeepEllumMusic]

TEMP-Kelivin and Spectrum are different, but the lamps may go through a heating process and cooling process (though very quickly) that will produce different color temps of the light and when you combine this with multiple lamps all on their own cycles you will not get a clear light-consistant Kelvin such as a flash or Tungsten lamp puts out.

I do know that Florescent lamps can vary over time since the balasts age.

Nothing like clear sky sunlight for consistancy, though that varies with the humidity, dust in the air, and altitude.

[gardener]

To be truthful, I don't believe I saw a single flash unit out there although there were some tiny flashes occassionally that had to be from p&s type cameras. Even the "staff" photographer didn't seem to use flash on his big black camera (looked like a Nikon) when he was on the dirt arena floor.
If you're thinking about trying flashes or slave flashes, the folks seem to be open to questions about this and that so it might be worth calling to see...

[ericf]

Your correct. I ment spectrum but stated temp. My bad