This set of images is grainy and not what I would normally post but I am doing so to show what goes behind a great image. Lots and lots of practice to get to the point of being able to focus fast enough to capture the bird as it leaves the water. The kingfishers are perched in a tree over the water and when they dive they do so with the intention of catching a crab they have spotted, and they do so at great speed.
The trick is to get the camera to focus on the bird as it dives into the water so that you can capture it as it leaves the water, bearing in mind that this is pretty much a split second situation so you have to be on your game. I found myself keeping both eyes open, one on the viewfinder and one watching where the bird was going, this allowed me to point the camera in the right direction for focusing.
In the past I have fluked a few really cool shots of the kingfishers diving but I haven't actually sought it out as the primary subject before. I can see it taking a good long while before I am satisfied with the results from this exercise.