Barry_Green
Moderator
Tungsten is worse for the CMOS cameras because the prevailing CMOS cameras (EX1 and RED) are both overly sensitive to infrared. I don't know if that's tied to CMOS or if it's just coincidental that both of these cams don't have strong-enough IR filtration, but tungsten lighting will wash your scene with more infrared than daylight lighting will. If your camera's subject to IR pollution, using tungsten lighting will exaggerate it and daylight lighting should minimize it.
I built a small 700sf greenscreen studio and lit it with $20 Home Depot shoplights with T8 electronic ballasts running high-CRI daylight fluorescent tubes, I think it's like $8/tube. That's for along the top. Then I fill in the sides with two CL655 fixtures, all daylight. Could just have easily been a jerry-rigged solution of banking more of the shoplights together, for that matter, but I used the shoplights for the permanent install across the roof; for the movable lights I wanted to use something more designed for the purpose. The screen itself is 24' wide by 9' tall and is lit with those six fixtures quite well. Four evenly-spaced 4' 2-bank daylight lights up top (would have been even better with 4' 4-banks) and then low and to the side I have some six-bank fluos. All light is at a 45-degree angle to the screen to make it all wash appropriately and smoothly across the screen. Just get your actors away from the screen to keep your actor lighting from polluting the screen's lighting (which would result in shadows on the screen, etc). I typically light the foreground with my CaseLites or Scandles, all daylight; also got a CL-SFT1 for a big softbox for $125, not bad but a little buzzy and not the best for getting close to someone you're going to be recording dialog on. For hard light the little Cool Lights 150W HMI works a treat as long as you can keep it away from the microphone, it also buzzes, moreso than the CL-SFT1. Basically the entire studio is daylight, and it wasn't expensive at all to outfit it that way. Plus it runs so much cooler (less A/C needed etc) and on less power (I think the entire place, fully lit, foreground and background, rarely pulls more than about 1,400 watts).
You'll get noticeably cleaner footage (and thus better keying) on a Red if you use daylight light. Don't know how the individual channels' noise shows on an EX1. It could just be the way RedCode deals with the blue channel; they've talked about significant image improvements in the next build.
Half-blue will help, 1/4 will help, but obviously they'll help only to the level that you add correction. Half-blue means it will have to gain up only half as much, thus reducing the additional blue channel noise by half. 1/4 Blue will mean it still has to gain up 3/4 as much, meaning 3/4 as much additional noise.
As for whether this will apply to your other cameras, it all depends on where they balanced their sensor. If they balanced for tungsten (and have adequate IR filtration) then going to daylight lighting will make for noisier images. If they balanced for daylight, then going to daylight lighting will make for cleaner images.
Should be easy enough to test though -- shoot your greenscreen as normal, then slap an 80A filter on the front of your lens and balance for daylight and open up the iris two stops, and shoot again (even under the same lighting). This won't take care of any IR issues, but at least that'd remain constant. Then take the footage into AE or somewhere where you can evaluate the individual color channels and see whether the difference is worth it to you. If you've got enough brightness as-is so that you can open up a couple of stops already, the 80A filter might be your entire solution (but I'd still look at an IR filter).
I built a small 700sf greenscreen studio and lit it with $20 Home Depot shoplights with T8 electronic ballasts running high-CRI daylight fluorescent tubes, I think it's like $8/tube. That's for along the top. Then I fill in the sides with two CL655 fixtures, all daylight. Could just have easily been a jerry-rigged solution of banking more of the shoplights together, for that matter, but I used the shoplights for the permanent install across the roof; for the movable lights I wanted to use something more designed for the purpose. The screen itself is 24' wide by 9' tall and is lit with those six fixtures quite well. Four evenly-spaced 4' 2-bank daylight lights up top (would have been even better with 4' 4-banks) and then low and to the side I have some six-bank fluos. All light is at a 45-degree angle to the screen to make it all wash appropriately and smoothly across the screen. Just get your actors away from the screen to keep your actor lighting from polluting the screen's lighting (which would result in shadows on the screen, etc). I typically light the foreground with my CaseLites or Scandles, all daylight; also got a CL-SFT1 for a big softbox for $125, not bad but a little buzzy and not the best for getting close to someone you're going to be recording dialog on. For hard light the little Cool Lights 150W HMI works a treat as long as you can keep it away from the microphone, it also buzzes, moreso than the CL-SFT1. Basically the entire studio is daylight, and it wasn't expensive at all to outfit it that way. Plus it runs so much cooler (less A/C needed etc) and on less power (I think the entire place, fully lit, foreground and background, rarely pulls more than about 1,400 watts).
You'll get noticeably cleaner footage (and thus better keying) on a Red if you use daylight light. Don't know how the individual channels' noise shows on an EX1. It could just be the way RedCode deals with the blue channel; they've talked about significant image improvements in the next build.
Half-blue will help, 1/4 will help, but obviously they'll help only to the level that you add correction. Half-blue means it will have to gain up only half as much, thus reducing the additional blue channel noise by half. 1/4 Blue will mean it still has to gain up 3/4 as much, meaning 3/4 as much additional noise.
As for whether this will apply to your other cameras, it all depends on where they balanced their sensor. If they balanced for tungsten (and have adequate IR filtration) then going to daylight lighting will make for noisier images. If they balanced for daylight, then going to daylight lighting will make for cleaner images.
Should be easy enough to test though -- shoot your greenscreen as normal, then slap an 80A filter on the front of your lens and balance for daylight and open up the iris two stops, and shoot again (even under the same lighting). This won't take care of any IR issues, but at least that'd remain constant. Then take the footage into AE or somewhere where you can evaluate the individual color channels and see whether the difference is worth it to you. If you've got enough brightness as-is so that you can open up a couple of stops already, the 80A filter might be your entire solution (but I'd still look at an IR filter).
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