I took this photo of my dog with the Canon 5D mark 3. This was shot @ 25600 ISO in low light conditions where you would normally use a flash. There has been no adjustment to this photo, no cropping no levels etc only desaturation.
I am quite surprised at the result. The photo has quite a lot of noise but not as much as I would have expected at such a high ISO. This photo could still be printed to 8x10 and give a respectable result.
The way the new digital cameras are going flash units will not be needed.
Cheers
Phil