At the moment any focal length will struggle to capture the action.If you are shooting large field sports (soccer, baseball, American football), you are probably going to want a full frame 400-600mm focal length angle of view. If you are shooting track and field, with full access to the venue, any focal length from 24mm through 400mm or even 600mm can be useful. If shooting from outside of the fence or from the bleachers, you are probably going to want 200mm - 400mm depending on your subject distance.