Hey, I am willing to buy a lens for surf photography. I used to have sigma 80-400 but wasn't sharp enough. Initially I was going to buy nikon AF 300 mm 4d EF prime, but I realized that will not be long enough for all the spots I am planning to use. Then I would go for Sigma or Tamron 150 - 600 with stabilization. But don't know which one is better. I guess sharpness will not be greater than the 80-400 I used to have. But should be relatively good till about 400 mm. Can somebody give recommendation for the mentioned lenses. Or any other lens I should consider. My budget is around 500 euro (or around 600 US...) thanx!