Amazon.com : Rokinon FE75MFT-B 7.5mm F3.5 UMC Fisheye Lens for Micro Four Thirds (Olympus PEN and Panasonic), Black : Compact System Camera Lenses : Electronics
What is a Wide Angle Lens? What Is a Fisheye Lens?
Opteka 6.5mm f/3.5 Fisheye Lens for Canon EF OPT65C B&H Photo
Midwest Photo Canon RF 5.2mm F2.8 L Dual Fisheye Lens