20D, 24-70 f2.8L, RGB shift-low light flourescent

[ronmayhew]

I had a serious problem with loss of color saturation while shooting my daughters basketball practice in a gym, poorly lighted with flourescent light.

Equipment: 20D, 24-70 USM f2.8L

The attached pics are representative, ISO 1600, f2.8, 1/400, sRGB, 70mm, WB set to Flourescent

I have greatly reduced the size in PS Elements, but the RGB shift is preserved.

Some shots came out great, most had some kind of color problem.

[yalemba]

With 24-70 f2.8L and 20D, I have experienced similar issues taking pictures in my son's karate class. The mat was pink, and because of its reflection on the ceiling, most pictures have the strong pink tinge...

[Tom W]

Flourescent lighting, and especially older units, do not light uniformly. There's a flicker of sorts, even if you can't see it (a lot of times, as the bulb ages, you can see it and it will eventually drive you crazy). Depending on where in the flicker cycle you take the shot, you may catch the light at its brightest, or its weakest output. The older lights operate on ordinary 60 cycle (50 in Europe) AC and will tend to fluctuate their light output at that rate, so if you catch it during the weakest output, the light will be dimmer and of a different color as well. Since all the lights in the gym are probably tied on the same phase, they will all fluctuate together.

Newer units often use electronic ballasts that convert to a higher operating frequency with a local oscillator, and will emit a much more even light. Also, phosphorous-like coatings in the bulbs themselves have improved and will stay aglow longer.

[AJSJones]

FLUOrescent lighting comes in quite a few "colors" - e.g., cool white, warm white, "daylight", Gro-lights etc etc so there isn't just one white balance associated with "FLUOrescent". One way around this is to shoot a white card under the same lighting and use it as a Custom WB, but as Tom points out, that would assume consistent and even lighting.
In the future for shoots like this (now you know when weird things can happen) shoot Raw and use the converter to set the WB for each shot (if they vary) or to develop an action for all the images. Since you specified sRGB and the WB setting, I assume you shot jpeg and not raw. If you shoot raw, make a mental note of what walls. clothes or whatever, in the scene(s) that you consider white. If you can recall for this shoot, use the gray eyedropper (under levels) to click on the "white" (or at least neutral gray) and you'll get the color balance real close.
This kind of dim and variable lighting is one of the examples to cite when explaining the benefits of shooting raw :-)

Andy

[Mike Panic]

shooting in school gyms is one of the top 3-4 hardest places to shoot... you NEED to shoot in RAW and then convert and adjust as needed

[ronmayhew]

I appreciate the replies.

I wasn't aware of the marked difficulties of shooting in a gym. But, given the poor lighting it is very apparent.

The flourescent flicker makes a lot of sense.

I did some work at an indoor skate park tonight, a much more modern facility. The results were much more satisfactory than the old school gym.