Photoshop Tip: Fisheye photo effect
Tips & Tutorials, by Mark White
December 24, 2012
The Spherize filter under Filter>Distort is ideal for creating fish-eye effects from normal photos
Set Amount to 100% for maximum curvature and after applying the filter add a blank layer.
Use the Elliptical Marquee tool to form a circle or oval, and fill this area with black
Boost the fish-eye effect by re-applying the filter once more for extra impact.