If using an oddball wide angle lens that doesn't appear in the Nauticam tables, is there a method to work out where the dome port should sit in relation to the front of the lens? (to enable me to work out what extension rings I should fit?). Hopefully there is a method that gets at least close so as I don't have to do too much trial and error!

https://interceptor121.com/2024/01/06/methods-to-determine-the-appropriate-dome-port-for-a-wide-angle-lens-in-an-underwater-housing/

Might be some help there?

DYI forum has some more info buried inside threads like this https://waterpixels.net/forums/topic/3672-3d-printed-curved-glass-macro-port-nikon-60mm-n120/page/2/

Just now, Sokrates said:

https://interceptor121.com/2024/01/06/methods-to-determine-the-appropriate-dome-port-for-a-wide-angle-lens-in-an-underwater-housing/

Might be some help there?

DYI forum has some more info buried inside threads like this https://waterpixels.net/forums/topic/3672-3d-printed-curved-glass-macro-port-nikon-60mm-n120/page/2/

Many thanks - will check them out!