Since the beginning of time fisheye lenses have been considered one of the most important lenses for action sports photographers. Not only are they a great creative tool but they actually make tricks and air’s look BIGGER (much like that font size which wasn’t done with a fisheye…)
It is very important to keep the lines straight with a fisheye, I know this may sound funny, but let me explain. Fisheye lenses create a huge amount of barrel distortion and the only place where lines remain straight is in the middle of the frame. Placing the horizon line in the center will produce more realistic images.
Fisheye lenses create a great amount of barrel distortion which means that straight lines toward the sides will become curves. Distortion becomes more and more prominent as these lines get further away from the center of the frame. By placing your subjects closer to the corner of the frame you will make them seem smaller and further always from the lens than they actually are, they will also appear bent and distorted.
Unless the athlete is centered, fisheyes work best when the athlete is not extremely close to the camera rendering them less distorted, and making the trick/air look bigger. Another huge benefit to the fisheye is that you will get huge depth of field allowing you to put subjects really close to the lens and still have everything else in focus. This works even at fairly wide open apertures!
True fisheye lenses have a 180 degree field of view enabling you to include an amazing number of subjects in the frame.
Just remember that to minimize distortion, you must make sure the horizon is in the center of the frame, choose a nice foreground and get low so your subject looks like he is going big! Forget all these rules if you’re looking for a really unique and artistic image that is obviously a fisheye shot.