I am thinking about buying a low light Nikkor prime lens for use indoors. I'd like to try taking photos around Thanksgiving and Christmas without a flash. Most of the living rooms of friends and family are about 12' X 20' I already own a 17-55DX F/2.8 and 70-200VR F/2.8. Camera = D70 Flash = three SB-800's I was thinking about a 50mm f/1.8D AF Nikkor. Will I notice that much of a difference between F/2.8 and 1.8? Or just use the 17-55 and SB-800's when needed? Cost is not the main consideration, sharpness at wide open and focus speed are.