What causes this yellowness?

[CRC]

...

[FlipsidE]

The only thing I can think of off the top of my head is that somehow the White Balance has been manually set and is not being calculated on each shot. Therefore it works great for some exposures but not for others. But, I could be completely wrong.

FlipsidE

[PacAce]

If that's happening whenever you open up the lens, no matter which lens it is, I'd say that you might have a problem with your camera. Your pictures are not supposed to come out like that no matter what the aperture of the lens is set to, especially if stopping down turns out a normal picture, like your second one.

[HKFEVER]

Try to re-set the camera to factory setting and test it again with different lens without filter. If it stay the same yellowness problem. Sent it in for service.

[tpinchback]

unless your wall is painted in a gradient off white color, then i would send your camera in to get fixed

[HKFEVER]

Even on the second picture, you can see the white is lighter on the top than the 2/3 of the bottom.

[aznkid.com]

i have the EXACT same problem with my 50mm f/1.8.. only under flurouescent i posted once on here and some thought that perhaps it was the flurouescent lighting that i was under which was changing..

[Olegis]

I don't think that there is any problem with the lens or the camera. Here is what you can do to verify it - set custom WB (shoot that white wall under that very lighting, make sure you fill the frame with the wall). After that your wall should be perfectly white on further shots, given the lighting conditions don't change - try to verify it at various apertures.

[Primevci]

mine does the same thing under florcents sometimes but not allt he times... but thats with a rebel not a 20d

[neil_r]

You could be looking @ the confluence of two diferent temerature light sources, flurouescent at the top and sodium or domestic at the bottom, the eye would not pick out this shift but the camera will.

Or I could be talking rubbish ?

N

[slin100]

I read somewhere that older flourescent lamps have pretty slow cycle-times. The top exposure could have been captured during the off cycle of the lamp, leaving only an incandescent to provide the light.

[DocFrankenstein]

I read somewhere that older flourescent lamps have pretty slow cycle-times. The top exposure could have been captured during the off cycle of the lamp, leaving only an incandescent to provide the light. Not probable:
The gradient would've been horisontal, not vertical because that's how the shutter moves. (unless the camera was horisontal)

How about using a single type of light and doing custom white balance?

[slin100]

Not probable:
The gradient would've been horisontal, not vertical because that's how the shutter moves. (unless the camera was horisontal)

According to canoneos.com, the 20d's shutter travels vertically, like most SLRs. You seldom see horizontal travel shutters anymore because it's harder to achieve the higher flash sync speeds (1/200 and shorter) you see today due to the longer distance the shutter curtains need to travel in the horizontal direction.

Actually, I think some shutters travel in an arc (not sure if the 20d does), but it's still mainly vertical.

[Olegis]

These pictures were taken with custom WB

That's strange. Do you get these results consistently with any fluorescent lighting (say, at your work or your friends house) or does the camera behave this way only with that particular fluorescent ?