The Tokina 10-17 zoom lens for APS size sensors zooms from 180 to 100 degrees and can focus very close. this makes it an ideal lens for underwater use. Today I tried it in the Nauticam 7D underwater housing with the Nauticam Nexus port adapter and the Nexus small multi-coated glass dome that will also support the Nikon 10.5 fish eye.
Here are a few images taken underwater with this set up. I chose an aperture of f8 to simulate a working aperture in the ocean. The lens was able to focus to the edge of the glass dome.
17mm setting 3 feet from the grid. The grid 50 inches wide.