Can I mirror iPhone camera output - without the controls?

Hi - in a pinch, I need to use my iPhone to feed live video to a projector. I have a VGA adapter, so I can mirror my camera, but I can't feed "clean" video without all the on-screen camera controls, etc. I feel like the answer is easy, but I'm flummoxed. Is there an app or way to get just plain camera output without the controls? thanks!