For an upcoming film I'm making I need to chroma keying to achieve many of the shots I need.
I am using three lamps with paper to diffuse them, a desk which is about a meter deep, a Quickcam Pro 9000 which is on a tripod (I jammed some lego in there to dock my cradle onto), some blue and/or green poster card, and dragonframe.

I've been fiddling around with the camera settings and the lighting to try to get a setup that gives me a clean blue backdrop, but I can't seem to work one out. I've been using the dragonframe chroma keying tool as a reference, and so far I'm getting purple or light blue differences in the deeper blue colour that I want, resulting in some varying degrees of success and mostly splotchy chroma keying. The subject has black parts which, because they are lego, reflect the background sometimes which makes it difficult to contrast them.

I will be using Sony Vegas Pro to do the final chroma keying in post.