Originally Posted by 94TurboGSR

Youmight find that you get better pictures if you set the ISO manually at 200-400 (your pics look like they were at 800 when they got really noisy). Crank up the aperture as high as it will go (2.8 on your cam, according to iEXIF) and let the camera change just the shutter speed. Your shots should be pretty consistent that way, and hopefully that will keep the noise down.

I personally hate auto iso on my camera, it seems as if it's always cranking up the ISO and introducing noise when it's not needed.