Zeiss 21mm Distagon lens

For quite some time I've been seeing some outstanding landscape images created by these lenses and I just wondered if anyone has used them underwater. The 21mm f2.8 seems to me to be the best option for an underwater lens, but I'd love to know if anyone has tried one or uses one regularly?

I have one and tried it for action shots only. It's nice but you need a big dome of at least 8" for the corners. I've used it on a Seacam, Aquatica and Sea & Sea housing on 5D2 and 1D series. Can't find any samples on my laptop, sorry.