Originally Posted by MidnightCommando 
OT:
6mm fisheye-nikkor on a full-frame nikon body, it's got a field of view of 220° and it's damned expensive. as in, better off buying a mansion.
I've got my eye on the Sigma 4.5mm but that's just a mere 180 degrees. But that should mean I can see behind me... as long as I'm laying down.
