Iso
 

hi does anyone think that if shooting a dark subject low light conditions:rolleyes: indoors at long slow shutter speeds could compound the noise at high ISO?

Most noise is seen in the blacks
Most high ISO shots have sensor noise
Dark subjects have blacks
Low light conditions require slow shutters and / or high ISOs
Slow shutters increase the chance of soft focus or motion blur

Your question suggests the answer to all aspects is yes!