Most people are very critical of silverstone, and i can understand why, however there is the possibility of getting some excellent pictures. The biggest problem I find is that I have to stand right next to the fence in order to get the camera to focus through it, which is somewhat restricting.
The longest lens I have is 200mm yet some of the best motorsport pictures i have taken have been at that track. Pictures from Abbey, Bridge, luffield and Priory usually fall within my 200mm range. "Standard" pan shots from the straight after the exit of club are usually possible too. Copse, maggotts, becketts and chappel will probably require in excess of 300mm as would stow, vale and most of club. The back straight between becketts and farm could also be good for 200-250mm, particularly at the chicane nearer the becketts end. I have never shot anything on the national circuit, except around luffield, so would have to bow to the experience of others on that. I would also concider taking something much smaller for pit and paddock area shots.
With some creativity and an 80-400mm you could achieve good shots from most places. Hope that helps. Good luck and I hope the weather holds good.
