I'm looking to buy a new zoom lens primarily for using at motorsport events such as F1, Moto GP, BTCC etc. I've been looking at the sigma 120-400,150-500 and also the Canon 100-400. The canon is out of my price range, as is the 150-500 as I haven't found that particularly cheap anywhere either. So would the 120-400 be suitable for these types of shots?
If you have any examples, i'd be keen to see them!
Thanks in advance