Tokina 12-28mm f/4.0 AT-X Pro DX Lens

Has anyone used this underwater? What are it's characteristics behind a 170mm, 200mm or 230mm dome?

On paper, the range seems perfect for 4k video on the Canon 1dx II, which has a roughly 1.3x crop -- effectively making this a 15.6mm-35.6mm equivalent lens.

Canon's own EF-S lenses can't be mounted on the full frame bodies, and the full frame wide angle lenses are too narrow (other than the 11-24mm, I suppose, but that's a beast!

Shot it this summer on my 7D2 behind a 170 Zen dome. Not sure if I got the port extension right. but It's certainly not bad with a 40mm port extension, AF works pretty well, but it's not as sharp as, say, the 8-15mm Canon.