# 7d colour cast problem?



## jaomul (Feb 15, 2012)

Hi all, I was wondering if anyone could shed some light on a problem I have with my camera. These 4 pictures were taken in a hi speed burst in av mode, all with the same metering and wb setting. They all look different with what looks like a moving colour cast. WB bracketing was not activated so they should all be the same. Any suggestions to solving this appreciated


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## Overread (Feb 15, 2012)

I'm not an expert, but many kinds of indoor lighting can have variable colour temperatures - our eyes can't see the changes in colour (its too fast) but cameras can and will pick them up. This is why studios use specific kinds of lighting that give a constant light temperature so that the photographer knows what they are working with.


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## MLeeK (Feb 15, 2012)

It's cycling lights. You can't see them with the naked eye, but the camera will see them every damn time. It's a PITA when you are shooting in a gym or similar.


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## CalamityCreekDesigns (Feb 15, 2012)

I am uncertain, but, I bet you are in a "Auto" WB mode. The camera is seeing different points every millisecond. 
Get out of Auto WB and see if  the issue stops.


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## jaomul (Feb 15, 2012)

Thanks all for the fast replies. I posted this on two forums and was cycling between them hoping to find my camera wasn't at fault. I got the same answer from both forums so relieved now as only bought it few days second hand and thought it was a turkey. Thanks again


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## Scuba (Feb 15, 2012)

Why did you take a "high speed burst" of a fire extinguisher?


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## o hey tyler (Feb 15, 2012)

Scuba said:


> Why did you take a "high speed burst" of a fire extinguisher?



Because he wanted to test how his camera was working? I've shot at more random things to check how my camera was acting in a particular situation. 

I see it is a sort of calibration.


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## jaomul (Feb 15, 2012)

Scuba said:


> Why did you take a "high speed burst" of a fire extinguisher?


I was just trying something out with my settings and used that as an easy focus point. I don't have the camera very long so chopping and changing a bit


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## jaomul (Feb 15, 2012)

O hey tyler, you got in as I was typing,pretty much spot on


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## o hey tyler (Feb 15, 2012)

Same wavelength dude!


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## Robin Usagani (Feb 15, 2012)

It is a phenomenon.


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## Scuba (Feb 16, 2012)

got ya.  I was just wondering.


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## analog.universe (Feb 16, 2012)

Since these color cycles in certain lights (mostly fluoro's, but also some of the HID type chemical bulbs), are cycling at the same rate as the current feeding them, you can average all the colors of the cycle by using the correct shutter speed.  Over here it's 60Hz, but I believe it's 50 on your side of the pond.  So if you set your shutter speed to 1/50sec, you get exactly one color cycle, 1/25 gets you exactly two.  You can keep going in even stop increments, and your color will be consistent from shot to shot.  I'd recommend using manual white balance when doing this however.


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## jaomul (Feb 16, 2012)

analog.universe said:


> Since these color cycles in certain lights (mostly fluoro's, but also some of the HID type chemical bulbs), are cycling at the same rate as the current feeding them, you can average all the colors of the cycle by using the correct shutter speed.  Over here it's 60Hz, but I believe it's 50 on your side of the pond.  So if you set your shutter speed to 1/50sec, you get exactly one color cycle, 1/25 gets you exactly two.  You can keep going in even stop increments, and your color will be consistent from shot to shot.  I'd recommend using manual white balance when doing this however.


I will keep that one in mind. It is 50hz here. I was at very high shutter speed before I got this problem and I was only trying a few things out. For my average day to day shots I don't foresee a problem but its still good to know how to avoid it. Thanks for the input


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## MLeeK (Feb 16, 2012)

jaomul said:


> analog.universe said:
> 
> 
> > Since these color cycles in certain lights (mostly fluoro's, but also some of the HID type chemical bulbs), are cycling at the same rate as the current feeding them, you can average all the colors of the cycle by using the correct shutter speed.  Over here it's 60Hz, but I believe it's 50 on your side of the pond.  So if you set your shutter speed to 1/50sec, you get exactly one color cycle, 1/25 gets you exactly two.  You can keep going in even stop increments, and your color will be consistent from shot to shot.  I'd recommend using manual white balance when doing this however.
> ...



Problem is then you must use flash if you have anything alive in the scene to stop motion. Most times when you will have this problem you'll be in a gym or similar and for sports your flash isn't even going to be effective to stop motion-most sports there isn't enough flash that will reach  your subject to stop any motion. Wrestling is a bit different because you can get pretty darned close to the action, however I don't think that with flash I could use 1/50 shutter speed. 
It won't change with a custom white balance either. The camera meters and sees white balance before you press the button, in that millisecond between the cycle can change. I find that I have a problem with about every 6th to 8th shot in a gym being very cyan or gang green looking on subjects. I am not generally shooting a burst or high speed, although it happens from time to time and that changes how many I  will have that are really whacked white balance. The whacked ones you can't fix perfectly either and the color temps and tints won't be the same as anything reasonable for the situation.


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## spotter (Feb 16, 2012)

Learnt something new today and it all makes sense. Light color cycles and camera white balance.


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## waycar71 (Mar 26, 2012)

Also, you may want to do test shots outdoors with the sun to your back and have a manual WB set.


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