Removing green yellow shift when using LED

E

eco_bach

Well-known member
Hi
Even when using an in camera custom color balance, I get an annoying green yellow shift with my 600 LED in my footage which I have to correct in post.

I don't get this shift with my smaller Z96's, but they don't give me sufficient light to replace the 600.
I'm also wondering if there is a 'break in' time with some LED's and whether this shift will go away.


Can anyone suggest a method to correct for this in camera, BEFORE the footage reaches post?


I though that was the whole purpose of doing a custom color balance, but perhaps I was wrong...
 
Some leds , especially the low CRI ( color rendering index) do have a native greenish tint that will not go away in time. Leds do exhibit a discontinuous spectrum that are deficient at a certain wavelength ( usually the magenta area) and that is the problem area. Natural daylight does not have that issue and also boasts the highest CRI factor as it has really no native color cast. Sure , it is warmer at sunrise and evening hours, but that is due to atmospheric influence. There are led units that do not have the greenish casts and a high CRI but those are few and expensive. I suggest using a magenta filter in front of the led light or the camera lens to correct the cast. How much CC magenta you will need depends on how bad the green is. Even with the CC correction filter, there will be colors that simply won't match up. Very tough, or impossible to white balance correctly for all the colors. Try to manually white balance on a sheet of white paper before the shoot and see if the resultant colors are correct, then save that setting as a custon function if possible.
 
Thanks. I DID manually white balance to a grey card but still had a slight but noticeable green-yellow shift. Surprisingly I DON'T get this shift with the very inexpensive Z96 LED's. I may try and gang 3 or more of these up as an alternative or get a half minus green filter
 
Why a grey card and not a white one ? A grey card is usually to measure reflected light as an exposure value to determine f stop/shutter speed and not for color measurements.
 
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