I would also recommend the zoom lens route or a really nice prime telephoto 400 or better. Watch the surfing events on TV and you see alot of long glass with tripods. Surfing mags seem to have both type of shots. I shoot my son surfing using a 300 2.8 with 1.4 and 2x converters and that is marginally enough. It is a good start depending on where you are on the beach in relation to the surfers. The zoom or telephoto would give a lot of use for other things as well. Racing, sports concerts and the like. Canon or Sigma make nice long lenses that range from outrageous to affordable. Get a good tripod or at least monopod to start with and you are on your way.