What version of Photoshop do you own? it may be to do with the profile you have loaded there is a free version of Rawshooter I can recommend the image does look a little underexposed and if you allow Photoshop to correct it you may get more noise.. Try a better lit subjecy first to see if this is a camera problem

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt