Ok. Testing out the Nikon D700. Imagine a very dark pub, band playing, people playing pool. You can barely see the outline of people across the room. Enter ISO 6400!
This was shot with 105mm at f2.8, 1/160 second…no flash. No alterations to the image.
Yes there is some noise, but more to the point is there is more light in this image than there was in reality. Reduce the shutter speed and you could reduce the ISO and get an even better shot. I was purely wanting to see what all the fuss has been about re high ISO. Now I know!