After three years with a D810, I upgraded to a D850, mainly for improved autofocus. Nauticam housing. Moved dual YS-D1 strobes to the new camera and set all to manual. Without the pop-up flash of the D810 or a TTL trigger, I can no longer do TTL. With manual triggering I was able to use a slightly faster shutter speed (1/200th). I generally kept ISO set to 64 for macro and experimented when shooting wide angle.
I used a Nikon 105vr for macro, a couple of times with a 1.4 teleconverter. None of the teleconverter shots made the cut. For wide angle I use a Nikon 16-35vr lens behind a 230mm dome port. I have been unhappy with the corners from day one, but this trip I tried a Sea and Sea Internal Correction Lens (77 mm screw on), and my lens was transformed. Huge improvement. Never shoot without it again.
The D850's focus is indeed improved and more able to correctly lock onto an erratic subject, as hoped.
These are all thumbnails. I linked to a 2K sized version underneath.
Edited by phxazcraig, 04 April 2019 - 11:31 PM.