Canon 8-15mm F4.0L Fisheye lens first impressions: you can't shoot wider than this:-) Photigy School Of Photography
Amazon.com : Opteka 58MM 0.35x Fisheye Wide Angle Lens Compatible with Canon DSLR Cameras Including Macro Close Up Attachment : Camera Lenses : Electronics
Amazon.com : Opteka 0.20X Professional AF Fisheye Lens for Canon EF EOS 80D, 77D, 70D, 60D, 50D, 40D, 7D, 6D, 5D, 5Ds, 1Ds, Rebel T7i, T7s, T6s, T6i, T5i, T5, T4i, T3i,