Next week I will be shooting a corporate video with the "look" of a typical late-night talk show.
We'll be using a nice big green screen cyc, shooting on XDCAM for later compositing in After Effects. Although I've shot plenty of green screen, this has a special challenge: The client wants the host (sitting behind his desk) and the "guest" (sitting in a chair) to be directly on the green screen, so that the virtual set extends under their feet. I suggested that we put them on a platform, or a piece of carpet.
We probably will not see many shots framed that wide, but I'm still concerned. I've always lit green screens perfectly even, and don't see a way to do that with a big chair, a desk, and two people sitting. I know that green screens can "take" a shadow as long as it matches the background, but this seems to be asking for trouble.
Well, you may have to do roto work on just the wide shots where the under-chair area is visible and under-lit. I don't know why people are always so scared of roto; maybe its just the tedium of it. Time=$.
Or you might apply extra iterations of the keyer to just that limited area. Or you compromise your lighting to get more soft diffused light into the under-seat area.
If you sat the talent on a couch or love seat instead of a chair, that would be easier than a stool type chair. More conventional for a talk show, as well, if the host is behind a desk.
Don't forget to put somme tracking points on the walls and floor.