Chroma keying and lighting?

[DAS19]

At my school we have about 10 professional lights that hang from the ceiling I wish I had the name but they are very expensive and we have a green painted wall. Now when we went to chroma key some of the bodies had shadows screwing it up a little bit. Any tips... all the cameras were on full power.

 

[Filmosity]

Getting good chromakeys is tough. I'm not the greatest at it, but I can offer some tips.

First, make sure your subject is several feet (about 6-9 feet at least) away from the green (or blue) screen.
Make sure the green screen is evenly lit, using lights separate from the ones you're using on your subject, with no hotspots or shadows anywhere in frame. Do not light the greenscreen with the subject's lights (i.e., key, fill, back, etc) turned on.
Light your subject normally, making sure you have a slightly warm backlight hitting the head and shoulders. Ensure there are no shadows being thrown on the greenscreen, and flag off any subject lights hitting the wall.
Know the background you plan to key in, and light the subject accordingly.
EDIT: Also, keep the camera's iris (I assume this is video) wide open, preferably at f2.8.

The key to this is good separation between the background and the subject. A shallower depth of field will help soften irregularities on the green screen, allowing for a cleaner key. And keeping those bodies far away from the wall will get rid of shadows hitting it and screwing up your key.

There are many more tips and tricks to getting a good key (I haven't even gone into the software and hardware solutions), but it can be done convincingly. Good luck.

 

[laurent.a]

Make a search with the engine on these forums, I'm sure you'll find plenty of advices - even ones I may have written but am too tired to write again, sorry -

 

[funkbomb]

Something almost nobody realizes is that if you light a greenscreen with just green light, you're taking out the unneccessary hues that white light reflects off a green surface. Try putting in what are known as "gels" which are transparent sheets of colored plastic that change the light's color. Those "expensive" lights you have are probably a parlight or fresnel. If you apply medium-strength green gels to them you'll have a good background to key from.