One of the coolest things about digital technology and how its expanding is that you are no longer limited to a film speed of maybe ISO800, and having to stop when you've reached the handholding limits of an F1.4 lens. Notice that with many of these high ISO samples you see, these ARE being shot with F1.4 to F1.8 fast primes, WIDE OPEN! And some are only achieving shutter speeds of 1/20 - 1/40 handheld, showing what both a super-high ISO and image-stabilization can do to expand our photographic capabilities into areas never before dreamed of in film days.
Here are some of mine, with a few different cameras and lenses:
Old school - manual focus, 35mm F1.4 lens wide open on my NEX-5N, ISO6400, no stabilization, 1/80 shutter speed:
NEX-5N, ISO6400, F4 lens wide open, handheld:
NEX-5N ISO12800:
A580, ISO6400:
A580, ISO12800, F1.4:
This was pushing it, mostly just for fun to see how the camera performed - my NEX-5N at ISO25,600, then stacked and screened for ISO51,200 equivalent:
NEX-5N, ISo12800: