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-   -   Colour Shifting (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/35101-colour-shifting.html)

Jordan Cushing November 17th, 2004 11:17 AM

Colour Shifting
 
I've been shooting with the XL2 for a couple of months now and on a couple of occassions I've noticed skin tones changing during shots, usually during camera moves. These green/magenta shifts are most apparent on broadcast monitors, but visible on consumer tvs too. Has anyone else noticed this?? I'm guessing that changing backgrounds are confusing the camera, but these have all taken place during fully manual operation. Could an auto WB be taking over? If so why, and how can I make it stop?

A. J. deLange November 17th, 2004 01:27 PM

I suspect it is auto white balance but it is certainly easy to confirm whehter that is the case or not. Simply duplicate a situation where you saw the color shift and shoot it again twice - once with auto white balance and once with manual. If going to manual eliminates the shift then auto was the cause. Lots of us shoot exclusively with manual white balance for just this reason.

Jordan Cushing November 18th, 2004 04:46 PM

Colour Shifting
 
Thanks for the reply A.J., but the puzzling part is that this has happened USING MANUAL WHITE BALANCE. So it has me wondering if certain conditions make the auto kick in (since that's the likeliest cause I can think of, it doesn't look optical, flare,etc).

A. J. deLange November 18th, 2004 08:36 PM

If you are on manual WB then the relative R, G and B gains should be locked. Nothing should cause them to change. Is it possible that when this happens you are following your subject into an area where the color quality of the illumination is different? An example might be an interior lit by windows where the subject moves from a window with nothern exposure to one with southern. Both daylight, but of different color quality. Another possibility might be another object (or person) which reflects light of a particular color onto the subject as it moves closer to or farther away from the subject or as the subject moves closer/farther relative to this object.

Jordan Cushing November 19th, 2004 03:15 PM

colour shifting
 
A.J., loving the theory, and glad to have some feedback, but I'm talking about an electronic shift of some kind. One example: a tilt down from a desktop to a person hiding under it, sidelit from under the desk. As her face appears at the bottom of frame it is pinkish, as the camera settles on her it has shifted to slightly greenish. The skin tones would both be acceptable on their own, but the change within the shot draws attention to itself. I'm assuming you haven't come across this with the XL2, I never had this happen in two years of shooting every day with the XL1 (or any camera for that matter).

Barry Goyette November 20th, 2004 09:31 AM

Jordan

In this situation you described, what type of light sources were present?

Did you have any kind of filtration on the camera (polarizer, uv...)? How about a w/a adapter

One other thought...you said this was most visible on your production monitor...is it visible on a computer screen...say a quicktime movie?

Barry


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