My port has a focus adjustment knob on it to allow you to focus manually. Works fine both with and without the TC. I purchased this and the extension rings from Ryan and Reef Photo. On my oder the port and rings are listed as:
I was wondering what your experience with the 100mm Canon Macro in the Subal housing is? I just acquired a C5 housing myself and I would very much like to start shooting the 100mm with a 2.0 TC. Have you ever tried that combination and is it possible to focus manually?
Subal FP-FC60 Focusport for the Micro Nikkor 60mm/2.8
Subal Extension Ring 20/3
Subal Extension Ring 50/3
This allows me to use the 100m macro with and without the TC