Nikon 10.5mm f/2.8 - Everyones favorite lens
This is the lens for everyone! Well not really everyone but many. Canon as well as Nikon panorama photographers have been using this lens for years with excellent result. If you want to use it with Canon cameras you need an adapter. Photographers with Nikon cameras with FX sensors are probably interested in the 16mm Fisheye from Nikon. But if you don't need the high resolution and are fine with the DX crop this is a nice combo.