@Phil Rudin
You are correct. Using an "SLR" lens with an adaptor on a mirrorless camera will yield no optical advantages or disadvantages, compared to using it on an SLR. Using a "mirrorless" lens on a mirrorless camera may produce optical advantages.
17 hours ago, Phil Rudin said:conclusion that a quality mirrorless lens like the Sony FE 14mm F/1.8 should result in better image quality than say the Canon EF 14mm F/2.8L II or Nikon 14mm AF-D on a DSLR of the same resolution and quality.
If this is solely a discussion about pure optical performance, I would expect that a mirrorless lens on a mirrorless camera should outperform an SLR lens on an SLR.
But, your post makes a a strange comparison, as neither of the SLR lenses that are selected are much used underwater, and indeed, the Nikon 14mm is pretty bad behind a dome port. I don't know how the Sony 14mm compares as it will depend on the nuances of the lens' design rather than its focal length. Many very good land lenses perform poorly behind a dome port, whereas some "poor" land lenses perform well...to state that a modern 14mm will outperform an older 14mm in our usage case is not de facto correct. It may, or it may not....
17 hours ago, Phil Rudin said:Sony has however filled in most of the other "pro" lens desires which is why the largest US news agency AP has moved to Sony, as has the largest UK news outlet, Canadian news outlet and others.
Until the AP has a dedicated underwater journalism unit, this statement has no relevance in choosing or discussing the perfect underwater camera.
