UPDATE: B&H has now matched.
Amazon is featuring the Rokinon 12mm f/2.8 ED AS IF NCS UMC Fisheye for Canon in a 5-hour lightning deal for $399.99. This price is only available for 5-hours or until sold out, whatever happens first.
This manual-focus lens is a fisheye (non-corrected perspective) lens that is designed for full-frame cameras. This is an extremely affordable full-frame fisheye that delivers great value, check out some samples at the Rokinon 12mm Flickr Group. Regular price for this lens is $489 at other authorized Rokinon dealers, this is an 18% discount.