great, thanks for the tips guys.

i just took delivery of one of the portable reversible blue/green backgrounds this morning as a start and i'm gonna use that as a basis for my experimenting.

I shall let you all know how we get on.

Dean - arri do a version of the tota lights and they're more available over here.
Also, thanks for the tip on balancing the green screen lights first - i wouldn't have thought of that one!!

Dean, I'm about to light a Green Screen with 2 Totas. Do you use the Tota Diffusion umbrellas? I'm wondering if the light is even enough without them. The Green Screen is about 10' wide.

Rob... You're welcome. Good luck with the project.

Craig... I just use the normal protective screen over the Totas without any diffusion. The coverage is broad enough so that two will handle a screen 10 feet wide. The texture of the EEFX.com fabric tends to diffuse light nicely and not get hot spots easily.

I also aim the Totas toward the side farther from the light. So the light on the left points toward the right side of the screen. The light on the right points toward the left side. They're also positioned about 5 to 10 feet from the screen, as far from the edge of the screen as I can manage in a studio that was about 18 feet wide. The studio I'll be working in next will be wider.

Stubborn black outline
 

Don't know if this discussion is still active, but here goes.
I'm shooting on green screen with an ancient DSR-250. It's 4:1:1 compression, so, not great...but anyway...
I'm getting this doggone black outline around my subjects that I can't get rid of. There doesn't seem to be any option to turn off sharpening in the camera. I'm using a magenta hairlight but still no go. Other than this black outline, the thing keys out fine. I've messed around with all the controls in After Effects Keylight. Shrinking the matte to get rid of the outline makes the subject look really unnatural. I tried Adobe Ultra which does a really good job of keying, but that crummy black rim is persistent. Any advice?
Thanks,
Lisa

Lisa...

I believe the 250 is DV format?

DV is the worst format to key. And as you noticed, the sharpening has created an artifact that's extremely difficult to eliminate. The green channel in the DV format has very low resolution, making it nearly impossible to get a key that even begins to appear realistic.

If your footage is interlaced, that's an additional headache.

There are plug-ins that might help interpolate a better green channel and give you a half-decent chance of success.

Nattress' "G Nicer" can help improve the green channel.

Nattress: Film Effects

But to be totally honest, there's no substitute for shooting it exactly right and with the proper format and color space. 4:4:4 is ideal. 4:2:2 is just as good. And 4:2:0 can provide excellent results. If at all possible, shoot in HD (not HDV). The higher number of pixels helps ensure better detail.

Keep in mind that with green screen it's the accuracy of the information in the green channel that allows any keying software to determine what's part of foreground and what's part of the matte. The better the integrity of that green channel, the better your composite will look.