I have only been in the pool with my new Nauticam NA-6400 and A6400 camera. So far so good. Everything is a compromise. So, that was the compromise I chose this time. It retains much of the portability of my FIX/S90 and has some of the DNA/engine of the full frame A7 Sony cameras.
I am a wide angle guy, so I bought the WWL-1. It is not heavy underwater and the whole rigs feels well balanced. I have two float arms and the buoyancy collar. I am using the WWL-1 with the kit lens 15-50 and the (now discontinued) Sigma 19mm (highly recommended). This gives a FOV of over 130 degrees. I also am working with my old Inon UWL100 with dome and the same kit lens 15-50mm as well as a eBay purchase Rokinon/Samyang 24mm. This gives a FOV of at least 120 degrees. Neither produce a full 180 degree fisheye but unlike a full 180 degree fisheye the corners are clean and seem well focused. Another compromise, clean corners and 130 degrees or distorted corners and 180 degrees.
I bought the TTL converter but thus far no success with that. I did get the extra battery packs. The basic rig fits in a Pelican Air 1535 carry-on case and is 21 pounds loaded. The arms and a few other bits go in my dive bag, the camera and lenses in my back pack. In the Pelican, housing NA-6400, the port and port adapter for CMC-2 and Inon, the WWL-1 wet lens, CMC-2 macro wet lens, two Inon strobes:
This is the biggest sensor I could get and remain portable and somewhat affordable (that being relative as I am quite poor now). For the Pelican I will eventually upgrade the interior to the Trekpac system to allow me much more room and I am ordering a lid organizer for all the caps, cables, batteries etc.
James