These are examples shot with the Olympus 8mm F/1.8 Fisheye, E-M1 II, Nauticam NA-EM1II housing, Nauticam N85 140mm optical glass dome port and N85 extension 17. One close focus and one at about 18 inches.
Not quite sure what you are asking. Both chart photos were taken with the type I ZEN 170mm port, one with a N85 20mm extension and one with an N85 30mm extension. I also had the type II N85 170mm port for testing long ago when it first arrived but stuck with the Type I port so I could use it with the 12-40, 12mm, papa 8mm fisheye and more. I have never own the 9-18mm zoom and my only use was for
My only use of the M 9-18mm zoom was for a review of Olympus E-PL1 in Olympus housing with ZEN 100mm port at for sharks at Stuart Coves and a fluorescence review using Ikelite EM-5 II housing, eight inch dome and fluor equipment. I used the 9-18 because I had a yellow barrier filter with the same threads as the lens.
These charts are to assist ZEN Underwater in evaluating some port and extension combinations. Most are sent on to Zen and not held on my personal computer so I only have these two examples of the ZEN 170mm port with 20mm and 30mm extensions. I am only one source for this information and Zen does not base their final recommendations on my charts alone.
I am far more interested in how the lens/dome combo works in the real world and what images sell regardless of corner sharpness.
All photos are with the Panasonic 7-14mm zoom in a Nauticam NA-EM1 housing. with the listed extensions, first photo (310213) 7mm at F/7.1 and 30mm extension, second photo ( 310103) 7mm at F/5.6 with 20mm extension, Both taken at two feet, Conch 7mm with 20mm extension at F/13, apex. three inches to subject.