Feedback time.
I just got back from a week cruise to the Eastern Caribbean, diving in St Thomas, St Croix, Antigua, St Lucia and Grenada, 11 dives in total. I use the rig (Nauticam housing for Nikon D810, dual YS-D1 strobes, V24 Fishlite) with the 230mm dome only once (St Thomas, the first day), and the 105 macro for the rest of the dives.
The system worked great. My first time using a DSLR underwater, and I'll do things differently next time, now that I have some experience. I can't really comment too much on image quality as it was *potentially* excellent, but limited in practice due to both murky water and (mostly) my ignorance for shooting DSLR underwater.
The DOME - my wife calls it 'Cyclops'. Here is a shot of me with it in St Thomas, and while the color balance is point-n-shoot typical, the water really was about that murky.
http://www.cjcphoto.net/caribbean2015/images/151213-062119-00-59-s120.jpg
In salt water, the rig is quite bouyant. I did not take off the floats from the arms, but I did end up adding 2 lbs of weight to get down! Underwater, the bouyancy wasn't much of an issue, but there were times that the rig really pointed itself straight up, and that helped tangle my air line into the strobe arm clamps a few times. (Trying to decide now if better to point the clamps away or not).
I put a +2 diopter B&W filter on the lens (Nikon 16-35vr) and left VR on. I found the lens to be quite sharp in the center, and very disappointing toward the edges. I'll have to try stopping down extensively there, which will require excellent lighting for reef shots. I was quickly shooting at ISO 800-1000 as it was, and F8, 1/125th as in this shot:
http://www.cjcphoto.net/caribbean2015/images/151213-032524-11-35-d810.jpg
I never had a shot with edges I liked. I'll definitely have to experiment a lot there.
My impression shooting that wide underwater - something very new to me - is that it's best done in incredibly clear water. The only time I wanted the dome on was in St Lucia, where I had near perfect conditions at a place called Turtle Reef.
I only shot with the dome for the first day. Why? Other than the need for clear water, it was 99% because the think is SO FREAKING BIG AND HEAVY! The logistics of getting my gear on and off the cruise ship to the dive boat were significant. I was carrying approx 60-70 lbs (half of that camera gear) over my shoulders. AND then also sometimes carrying another 30 lbs of my wife's gear when she was struggling. I don't ever want to do it again without some sort of wheeled luggage to truck some of that around. I was carrying the camera mostly set up (except strobes) in a 36 can AO cooler bag, which served as my dunk tank back in the shower of the cruise ship. It was definitely easier and lighter to have the macro port on there, and I couldn't figure a way to carry both ports with me to the dive boats.
So - 2 dives with dome port in poor conditions. Can't judge too much from it.
The MACRO - compared to the dome, it was a breeze to carry. Slightly negative underwater, I could dive with my usual 8 lbs, but I ended up going with 10 to make it a bit easier to stay down on the bottom trying to shoot small critters.
The 105vr - I really like it, but sometimes hate it too. I like it for all the reasons one likes a 105mm macro - plenty of working distance. I hate it when I can't take a 'normal' shot because the angle of view is so narrow. I'm so used to a camera with a zoom lens like the RX100 or the Canon s95. You would have no idea where I was diving based on the shots I could take. On the other hand, I could get shots that were impossible otherwise. I'm starting to consider goofy ideas like carrying a second camera (point-n-shoot) with me somehow to get ambient shots (or close-focus shots if diving with the dome).
I like the challenge of diving and photography put together. It's a good thing too, or I wouldn't be happy with the logistics of carrying and diving with that big of a system.
I still need to get closer, to mostly fill the frame with a subject instead of relying so much on cropping. Doing that with surge presents a lot of challenges for me.
Here's a shot of a Bearded Fireworm in Grenada:
http://www.cjcphoto.net/caribbean2015/images/151217-034734-96-20-d810.jpg