Opteka 6.5mm f/3.5 Fisheye Lens for Canon EF OPT65C B&H Photo
Amazon.com : Opteka 58MM 0.35x Fisheye Wide Angle Lens Compatible with Canon DSLR Cameras Including Macro Close Up Attachment : Camera Lenses : Electronics
FAQ: What is a Wide Angle Lens? - 42West, Adorama
Altura Photo 8mm f/3.0 Fisheye Lens for NIKON DSLR Professional Ultra Wide Angle Aspherical Fixed Lens
Pentax K-70 DSLR Camera with DA Fisheye 10-17mm f/3.5-4.5 ED