red channel when shooting raw

Hi - when shooting greenscreen and RAW codec I've noticed that my red channel is pretty bad compared to say red one...is there a way to fix this - would an IR filter help?

thanks
klaus

what do you mean "bad"? Can you post some visuals?

here:

Wow, I've never seen the red channel like that. Normally the blue. No over exposing?

well, it looks like all that noise is just in the green screen area yes? Does this show up if you shoot ProRes?

What filters are you using? how are you lighting the green screen? What is your exposure on the greenscreen at?

could you please post a dng file

Hi - i've tried prores once for greenscreen but only with a chromaflex...not brilliant but client insisted...the shot i'm referring to is quick and dirty - shot after the greenscreen was taken down and we realised it was a shot we needed so greenscreen is not even in the slightest, lit with to kino's. Not sure about the exposure on the gs, but i had this problem before at a theater with the gs evenly lit with two theater lamps of some sort (apparently the standard ones - not sure what they're called) - i'll see if i can find dng from that but i think i only have the prores that the client wanted. I'll post a dng from the shot in the pic here later.

The issue has not been a big problem, i can still pull a pretty decent key, but it has happened twice now, so just wondered if any one else had this problem - plus it takes a little bit more tweaking than a red shot...

definitely not overexposed anyway...

definitely not overexposed anyway...

I was thinking underexposed actually. If you underexpose green, you will definitely get more noise int eh red channel...

he, he - well not under either I would think - but not sure. Here's form another shoot - this is from prores, but it was shot RAW. I see what you mean - the problem is by far worst in the darker areas of the GS but don't like the "fringing" in the one with the boy - i'll upload a dng from that next (bear in mind that this was a quick and dirty shot)

here's a link to a dng:
http://www.hightail.com/download/OGhlNU1CbEEzS29kVU1UQw

On thing though - i have always converted to exr before pulling a key (nuke doesn't read cinemaDNGs - least not to my knowledge) - is there maybe something i do wrong in the conversion?