Thanks, obelix and paddymac .
The lense I was using, EF 70-300mm (not L version).
Every lense has sweet spot when you find it, strict with it unless you needed to...
They were not far away from the beach.
see the heigh resolution here http://www.bsctn.com.au/pinnaroo-point-8-12-13/
Neng, thanks so much for these !
I asked someone to take some photos last Xmas.. just so I had some kind of photo of me windsurfing, but they only took photos of me sailing because they didn't understand the sport. They also didn't want to take any photos of me stacking it, but the stacks are a huge part of windsurfing... bigger the better (ha ha).
The way you anticipate the photos, are in the right position relative to light, the sailor etc etc - and picture quality etc shows amazing talent. Your passion for photography and water sports is really inspiring. Brett