"I too am contemplating adding the dome port to the lens, but because of the results I am getting without the dome port, I'm thinking I may buy another UWL-100 and add the dome port to that one, and that will allow me to exchange lenses underwater when I need a wider angle, such as when I photograph wrecks, which I often do."
Hi Adrian, thats my solution too.
However I find switching the UWL-100 and dome unit a fiddle with the M67 thread and is a situation waiting for a dropped and lost lens...
Also, the lens and dome is a big chunck of glass to find a home for when its not on the front of the housing.
So I tend towards diving the straight UWL-100 and UR Pro filters on the short port and I look for macro or portrait opportunities with it removed (not ideal with the short port) and popped into a neoprene bag.
"BTW, with the Patima Housing and the short port, and the UWL-100, which I never zoom, I have found no blurring or distortion at all - It's an amazing lens!"
Agreed! Unzoomed its fine.