What's the problem here with the yellow gradient?

[dleone]

Hi all,
Been taking some pictures today at the daycare of my little one and after loading the pictures into Aperture I noticed that many of the pictures show a yellow gradient. It totally varies from none to useless and it's particularly obvious in stack I got from continuous shooting. It's quite frustrating - about 50% of all the pictures I have taken are useless like that, there are a few that don't show any gradients.

I've used two different lenses at the event (35L and 85/1.8), so it's not a problem with a lens (or the filter in front of the lens). I've used a 5D for these shots.
Notice how the background (snowmen at the wall) in one pair of pictures varies and the foreground (marshmellows) varies opposingly.
The fact that it's gradients indicates to me that it's not simply white balance that's off.
Does anybody have any suggestions?
Many thanks in advance

[dleone]

here's two more examples.

[Deckham]

Strange.
Looking at your last two, settings are identical. So i can only assume that the camera has used a different point to calculate (auto) wb.

[WilliamL]

could it possibly be a problem with your flash? with the little boy picture.. maybe the flash had a full charge for the first picture and only a partial charge for the second shot..

i may be way off base here .....

[Deckham]

could it possibly be a problem with your flash? with the little boy picture.. maybe the flash had a full charge for the first picture and only a partial charge for the second shot..

i may be way off base here .....

No flash is registered in exif.

[FREEZE]

how about florescent lighting would that cause this?

[Scott_Quier]

This is taken under florescent lighting and your shutter speed not being set to a correct value. For best results your shutter speed needs to be a close multiple of the power frequencey. In the USA, this is nominally 60Hz so your shutter speed needs to be one of 1/125, 1/60, 1/30, 1/15.

[Jon]

Except that I wouldn't go as fast as 1/125 sec., that's correct. Your shutter needs to be at a speed that'll catch one full cycle of the lamp from peak to peak. If you're at a shutter speed faster than the flash sync, you'll see banding, since the entire frame isn't exposed at one time. If you're between the sync speed and the lamp's cycle rate, you may get "funny" exposures since the instantaneous light level isn't what the meter (which gets an average) saw.

[dleone]

you guys are great!!!!
So that's why I see more of the banding in the pictures I took with high ISO (even shorter exposures). Essentially, I should be shooting in manual mode, right? Keeping both aperture and exposure time constant at 1/60.
I'll have to try this out again.

Thanks so much for the tips. What an eye-opener!
Dino

[Deckham]

smacks head
Thanks for the info, guys.

[heymirth]

I'm so glad they keep this stuff on line forever
This just happened to me this weekend,,, any other thing I can read o this?