Thank you very much for the replys and hints to the reviews.
What's your reason for upgrading? I have the 8mm Pany used with the Zen 100mm dome and It's sharp except for the very corners. Here's an example:
I love my 4.33" with Pana 8mm since it is so small and light. Very easy to travel with, especially when I am also taking my dive gear, tripod, drone, etc. and it is possible to get very close.
However, I finally would like to take great split pictures. The 4.33" is just to small for it as soon as you have a few ripples / waves. Of course bigger domes are better for split pictures due to more space between lens and water. But changing to another lens (Pana 8mm-> Oly 8mm) to be able to use the large dome (Zen 170mm) is a big investment, which at the same time makes it harder to travel with.
Simply upgrading to the Nauticam 140mm which can be used with my Pana 8mm is definitely the cheaper and lighter option. But will the dome diameter upgrade be big enough for my taste, I don't know since I never tried a large dome.
Going to the back issues in uwpmag.com again, a free PDF download I have the following reviews. Issue #64 Pana 8mm N-4.33, #97 Oly-8mm with N-140.
Thank you for the very informative reviews in the magazines. Unfortunately there is only one sentence regarding split pictures "I found the Nauticam 140 mm port worked well for split images in relatively calm water, using f/8 and above." with the Oly 8mm + Nauticam 140mm + extension ring.
By judging from you model pictures above it indeed looks pretty good (with the 12mm and so presumably even better with the 8mm) at least in very calm conditions.
I have to think about it, but will probably go with the 140mm dome due to its overall benefits compare to 'just' easier split pictures. Thank you very much everyone
Edited by world.explorer, 21 May 2019 - 08:41 PM.