What IKELITE port extension for 1.4/24mm Canon ?

Hi, it is not easy to know what is the best extension port for my DOME 8" and Housing 5D ?

I used the 5510.16, but the pictures are bad, problem of deph !

Please can you share your experience ?

Thank you very much

Did you have a look at http://www.ikelite.com/web_pages/2port_canon.html, it mentions there you use #5510.16. I am not sure what you mean with "deph". If you do a forum search on corner sharpness, you will find many posts on improving rectangular lenses behind ports...