Limited out in the dark (at 320/s) The D4 cranked it to the max on this bear, straight from camera, my first time hitting those numbers so I thought I'd share
When forced to use high ISO and if the scene allows it, try over-exposing the subject by a stop to greatly reduce the noise level. Just don't go so far that you lose highlights that you want to keep. I expect you might have lost little detail in the stones and tree trunk but gained a lot on the bear so long as it was not moving too fast and in the vegetation.
How did you take this photo ? I would have used M exposure mode to set the shutter speed I needed for the action and camera motion and set the aperture I needed for DOF and let auto-ISO take care of the exposure (along with any exposure compensation that I dialed in). The only problem is that with this approach I cannot use exposure bracketing without the camera changing the aperture or the shutter speed. Nikon almost got it right.
F4 I believe, was at 5.6. I could have slowed the shutter down to lower the iso but last time I was at 200/s with the 300 F4 the images weren't as sharp as I hoped.
I was just shooting while I waited for my mother to finish, I knew the images weren't usable, she was shooting at much lower shutter speeds, but I can guarantee they'll be blurry , but yeah, I wish I had a flash light walking out of the woods :P It wasn't hugely dark right then though. But 320/s + F4 = high iso.
I thought - exp comp would lower the iso, he is already overexposed slightly imo