Actually, it isn't a new lens after-all... I have had my Tokina 12-24mm f/4 ATX for years but, I had never before used it on my 5D2. This Tokina is a crop camera lens with an EF mount. I had heard that it could be used on a full frame camera up to the point when it begins to vignette - which is about 17-18mm on my 5D2.
There actually is a slight bit wider coverage using this lens on the 5D2 with the restrictive focal range and using it on a crop camera with the capability of using the full focal range of the lens...
These shots are from the 5D2...
18mm
24mm
18mm