After several years using Nikon FX underwater (D700 and then D800) last year I went back to DX when the D500 was released. I based that decision on my experience over the past few years since I got in to "big animal" trips - starting with the humpback whales of Tonga. Basically, up till then I did not see any real need for high frame rates and super-fast autofocus - but being in the water with those huge animals changed my perspective and I ended up quite frustrated with the D800 I had as my main camera and the OM-D E-M1 that was my back up.
So I sold them and went for the D500, Nauticam housing and initially the Tokina 10-17, which had sat on the shelf for a number of years.... I have just completed 3 weeks in Mozambique and South Africa using the new Nikon 8-15 and the Nauticam 140mm dome and am over the moon with that combo. Which, when combined with two Sea & Sea YS250's (hernia model...) is, in my opinion, an almost unbeatable set-up for large animals at the overall price point it all comes in at.
All that said, I am intrigued by the Nauticam WACP and Alex Mustard's excellent review of it. And while not 100% convinced I could justify the expenditure so soon after buying my current rig, I decided to buy a good sample of the Nikon 28-70 3.5-4.5 while they can still be had cheap.
I tried it initially on the D500 but scared myself when I heard the noise coming from the old-fashioned A/F system on it when driven at speed by the D500. I got back to my place in Bali last night and tried it on my D750 "land" camera and it was OK, but still a quite noisy.
So.... I wanted to post a few questions and see what other people's experience may have been.
1. Reviews of the 28-70 say it is a good lens that is quite sharp, plus it is small and seems to fit the bill for what Nauticam were looking for. And, as Alex pointed out - the dome is the restriction, not the lenses. But... can it cut the mustard (slight pun intended...) when it comes to using it with fast moving, big animals?
2. It seems like the excellent degree of coverage of the 28-70 behind the WACP would be best suited to "big picture" reef scenics?
3. If I do decide to "invest" back in FX and the WACP for underwater, I am wondering whether the D750 is a better choice than a D850?