Think like an interrogation. Theres a spot light or desk lamp being the only wanted sources of light. This causes havok with grain. How do you make it so the light just falls off into darkness, not fall off into lots of grainy darker spots. Is there a way to tell the camera to not grain dark areas ? The background may still be visible, but i just want it dark...not speckled with color or b+w grains. Is this in cam controllable? Or is it all done in post? Any help would be great.

I would set your gain to -3. Setup your shot and try not to overexpose. I am guessing the main light will be pretty intense. You should have plenty of light to expose just your area and the darkes should be....just dark. Not grainy. Also, in contradiction to what I already said above, you may want to overexpose the subject a little here and there to exxagerate the intensity of the light. This is a subjective artistic choice that you may or may not want to make. You could also expose properly and do the blowouts in post where you have more options and can change your mind without re-shooting.

However, back to what you originally asked: Leave the gain a -3 or 0 and your shot should be clean. I know that if I was ddoing this shot I would not be worried at all. The H1 can clean house when at -3 gain. Shoud be very little grain. IMHO

i tested out some settings, getting more brave and playing with the custom presets. I put grain on -3 like you suggested, gamma to cine 2 (not quite sure what that does...i know it adjusts gamma...but well the tech side of it i don`t know), i`m at about f 4.8 with zebras on 85. PED (?) -9 and BLK set to press. I think thats all I changed and it looks really moody and nice.

New question. Since the spot light is over head, how can I diffuse the sharp shadows it casts from out stretched arms over the desk thats got the spotlight (lamp) on it? I want that to be the only light source noticeable... are the shadows forgivable given the circumstance?

*EDIT* Nevermind...the shadows make it more moody and nice looking. Thanks for your help