Also assuming that you have proper lighting and no gain, but you're still not happy with the noise, consider Raylight MXFX which is a footage preprocessor that can reduce noise and rotate the image as well (while fully preserving the P2 contents). The Mac version was recently released. The advantage of preprocessing over a noise-reduction plugin is you are not re-rendering the noise reduction every time you export a cut. See
http://dvfilm.com/MXFX