Looks interesting for those that are fans of rectilinear.

Temping to get one and play with

https://www.diyphotography.net/laowa-15mm-f4-5-ultra-wide-meets-macro/

https://youtu.be/szG4XcmqG90?si=PW_RoW4lG2JQDn-X

A drawback is that it is manual focus only...

In addition to being a manual focus lens requiring a custom focus gear the lens at 1:2 is only 1.42 inches (36mm) from the front of the lens. This means that in a 230mm port 1:2 would be inside the dome port even in a 180mm port sharp minimum focus would be inside the port. This means you won't be able to take advantage of minimum 1:2 focus or anything near it.

Laowa has the 10mmF/2.8 AF in Sony and Nikon Z mount with a 12mm F/2.8 coming this year. The 10mm focuses even closer than the 15mm at 12cm and works very well in the 230mm dome with focus to the dome port.

I owned the original version of the Laowa 15mm which also focused to 1:2. Great lens for nature in air but not very useful underwater.

You can read my Laowa 10mm AF review at uwpmag.com in back issues.