Nauticam Domeport and Extension Ring Issue

I have the Nauticam NA-1DXMKII housing and I would like to use my 16-35mm f/2.8L III lens. My question is, can I use my 8.5" acrylic dome port and if so what extension ring would I need to get?

3 hours ago, cksmy said:

I have the Nauticam NA-1DXMKII housing and I would like to use my 16-35mm f/2.8L III lens. My question is, can I use my 8.5" acrylic dome port and if so what extension ring would I need to get?

 

The port chart shows all the recommended extensions required and can be found here:  https://drive.google.com/file/d/1Azu-13FMlXxDZeHaIkLwYajHpMzqcpqF/view

They don't list an extension for the type III lens however you will note that the extension required for the 8.5"port is 10mm less than that required for the 230mm dome port.  Likewise the same extension is recommended for the 180mm and 8.5"ports.  The recommendation for the type III plus 230mm dome is extension ring 70 plus 20 = 90mm extension, so you would be looking at extension ring 80 - 21180.

It will work but the corners will not be as good as the 230mm port at the wide end (16-18mm), that's basic port optics no matter which wide angle lens you are looking at, some people posting here complain about the corners with the 230mm dome and insist on adding the S&S correction lens.