How fast is fast?

So far, I have never written about my camera, a Nikon D3 with a AF-S NIKKOR 24-70mm f/2.8G ED lens. But I think I just like to show two of my photos here taken at an event in Boulevard carpark Miri on 29 March 2009. While wandering to the stage area, I saw a martial art demostration. But I couldn't go near the stage as there were so many people. Anyway, standing some distance away, I decided to take some pictures.

Nikon D3 f/2.8 1/1250 sec ISO-1800 EV: -2.7 70MM no flash.

As this was my first time taking real action under some colourful spotlight, I have to experiment. Initial shots were blur because the shutter speed was too slow until I crank it up to 1/1250 sec. Only then I manage to "freeze" the action. Nikon D3 f/2.8 1/1250 sec ISO-1800 EV: -2.7 70MM no flash.

The two photos above were not retouched other than cropping and resizing. There is no noise/grain visible.