I’m thinking of getting a Nauticam 9” N120 glass dome for my S&S D850 housing. Does any have good success with this setup? If so, which adapter do you recommend? There is a replacement NAM0142 port adapter and the 20mm extension #21520, that seems to be able to do the trick.
The lens I shot WA is Sigma 15 and Nikon 16-35. While, I have no issues getting the recommend 80mm extension for S&S on the Nikon 16-35mm, the 0 extension for the Sigma is the differentiator. I rather use the #21520 and not mess with changing out the port adapter that is attached to the 9” dome. What would the 20mm additional extension do to the images from the Sigma?
The issue with 15mm dome depends on how it is setup with the dome in question. Adding extension places the lens further back in the dome if the lens is setup with the barrel mostly inside the extension then adding some extension means it is more likely that various parts of the dome are going to end being in the field of view and it will vignette. The 230mm dome port has a hood and this is a likely source for vignetting. Whether it does so or not you would have to test. The good thing about vignetting is it is easy test in the shop.
There is is really no benefit in using the big dome with a fisheye lens apart from not needing a second dome to accommodate your fisheye lens and the bigger dome makes it more difficult to get in close for CFWA shots.
