Lewis88

To which APS-C fisheye lenses are you referring? If you mean 7artisens and other MF lenses, it's because they're MF. MF is complicated and finicky underwater, especially in less than perfectly calm water. Sigma makes a canon mount 10mm APS-C lens which you can adapt, but it's more expensive than a tokina.

FWIW, one of topics linked was my own topic on wet pixels. I just pulled the trigger on a used 50mm zeiss touit lens per @dentrock's recommendation. Spent hours researching the 50 vs the 90 vs the canon. The 90 is just too tight for me, and the price of the Nauticam port for the canon is really what threw me off, as well as having to carry another port all together. The 50mm lets me use my kit lens 45mm port with a few extensions. Once the lens gets here, I will order a pair of n85 17mm extension rings and see if 1mm less port will still fit the lens (compared to the port charts). Else I will switch for a 17mm and 20mm extension ring combo, leaving me with 2mm more than the port chart. I will likely even try the lens in my zen dp100 dome I use for my tokina, just to see how it does. Debating if I should even keep my 16-50 kit lens and diopter, or just switch fully to either macro or fisheye (tokina). Not sure how much use it'll get anymore.

Yes. Using this one: Nauticam N85 to N120 50mm Port Adaptor II (backscatter.com)

I also shoot the Tokina 10-17(via Sigma MC-11) on my A6100 in a Nauticam A6400 housing. Using the Zen DP100. It's on my camera probably 75% of the time. Absolutely fantastic and tiny setup.

I personally would not trust any FDM part underwater. I would only be trusting an SLA part, which once you get your part designed, you should be able to get printed at most any print house. Fusion 360 is probably the simplest free modeling tool, and with youtube and some calipers, you might be able to model both connections.

Great post, and it's exactly why I love my Tokina 10-17 on my Sony APS-C setup. It's on my camera probably 85% of the time.

I'd go back button focus with focus peeking, and rock the camera back and forth to get the DOF where you want it. UW MF for super marcro sounds overly complicated.

Waiting on some real world tests of the Marelux Apollo 33's.

Good to be here, and hope we see this community thrive without the previous site's drama.