I'm looking to upgrade to a new body soon and wan to know how the 1Ds MKII series camera compares to the new 50D, 7D and 1D MKIII ISO for picture quality in low light condition.
Also, I notice more grain in my images with my MKII body while shooting at ISO 400-500 with 1.2 or 2.8 lenses. Could this be sensor wear and tear or is it time to upgrade to a newer camera sensor?

