What can't 1/1000th of a second freeze?
The following image shows 4 images captured in a sequence at the Malaysian F1. It shows a 50% crop of the last 2 images in the sequence, the settings were 1/1000th, f/5.6 at 300mm.
Why was the last image that blur? Because when Alonso went off the track, the crowd in the grandstand stood up, and in a Mexican wave, people stood up from front to back almost in a split second. As I was in the last row, the people in front of me suddenly stood up and as I was firing off the sequence, my lens was obviously knocked. And 1/1000th is not enough for freezing the subject plus freezing the 2-axis sudden movements of my camera/lens combo.
That's what it can't freeze. Remember to check out my webpage www.lioneldudephotography.com for more updates this year.