This was my original Sony RX100 rig built around the Nauticam RX100 housing.
The configuration had 3/4″ locline arms that proved to be a bit too stiff in water and a modified FIX ADF-PRO mount to accept Inon AD lenses.
Due to the cropping in active video I could use the Inon UWL105AD without vignetting though I had to remove the filter ring to avoid vignetting using the filter. I took this set up in Raja Ampat and worked pretty well allowing me to take mantas and pygmy seahorse on the same dive thanks to the wet lenses.
I then dropped this set up for a Panasonic LX7