I shot extensively with the Canon 8-15mm f/4L fisheye zoom while in the mountains last week on a photo tour, using it both as a full-frame fisheye, but also as a circular fisheye, on the Canon 5D Mark II.
See my review in DAP.
It's a hard lens to use well (all fisheye lenses are), but tons of fun. Definitely a lens to have in the Canon shooter’s bag, and I wish Nikon made a similar lens.
I’ll be posting more content to my review very soon.
At about $1499 it is reasonably priced for the unprecedented fisheye zoom versatility.
See my handy list of Canon gear at B&H Photo. When you use the links from this site, we get credit, thank you.