Nikon D300s video has too much noise?

I'm shooting some video with my Nikon D300s and I've noticed there's an insane amount of noise. I'm in A mode, I've opened my aperture all the way because I know that if I put it low the iso would bump up, and I've got a pretty good amount of light. I've got natural and all the lights on in the kitchen (thats where i'm filming) as well as two powerful external lights.

Can you Please tell me WHY there's so much noise! I don't understand what I'm doing wrong.

Is your ISO in auto also? You might be forcing it to a high ISO.

Set ISO to lowest.

If it's not the sun, it's not natural. Check White Balance too. Sometimes Auto does not get it right. Keep ISO below 1600. Remember, the camera does not see like human eyes. What is low light to you may already be pitch black darkness to the camera so learn to adjust.

Are you sure you have "opened" the aperture? "Open" means low numbers such as f1.8, f2.8, f3.5. Numbers such as f11 are small apertures, nearly closed.

Try setting the lowest number you have on your lens and shooting a test. With powerful external lights you shouldn't get any noise. In fact you shouldn't need much supplement to the lighting in a bright kitchen.