Even though my wife and I both have OM-D cameras in Nauticam housings (mainly for weight and travel considerations) I kept one of my Canon/Nauticam rigs.
It is a Nauticam NA-600D housing with the Canon 700D installed. All the functions work except the ISO button which I assign to the OK button and the on-off-video switch which I leave in the on position and have the camera auto power off after 4 minutes.
One of the buttons had come dislodged so I sent it to Nauticam Australia at Scubapix in Cairns, to fix the button and install the vacuum electronics. I got it back after a week or so with vacuum valve and electronics installed. Both our OM-D rigs have them fitted and they are excellent and reassuring during the dives.
The major draw back of the mirror less cameras during diving is the limited battery life which during 2 trips to Bali, the batteries were exhausted early in the third dive of the day. My Canon cameras over the years have easily coped with 3 dives with plenty of power to spare. The focusing is still faster with less hunting on the Canons too.
Another problem I experienced with the OM-D E-M1 is the rear dial only working 20% of the time. A quick Google revealed it was a common problem and the shop where I bought it swapped it for a new one even though it was 6 months old. Hopefully this one will be ok. Never had a fault with any of the 7 Canon DSLRs I've owned so not ready to switch full over to mirror less and will enjoy the best of both worlds!
