The way you “froze” the water makes it look like a swimmer just came out of the water
Bent, thanks for your comment. This was mostly a lucky one, as the duck was diving its face into and out of the water very quickly, and most others I took were mis-timed. Auto-focus was also having difficulty. For birds I set my camera up to use dynamic 9-point group AF, which works well for me for tracking birds in flight. However, for a photo like this d-9 AF tends to lock on to bright/high-contrast water droplets flying around the subject and results in a lot of well-focused water photos and not so many in-focus birds (it happens a lot when I'm taking photos of ducks, gulls and geese landing on the water). I guess single-point AF would fix the problem. I should set up a button to alternate between d-9 and single point AF, as Peter mentions in a reply a bit further up this thread. Cheers again, John