[GeorgXXL]

The APD is a "gradual aperture". So, the further you go to the edge of the element, the less lights goes through. This results is more DOF, just like stopping down does. You get less isolation with APD from Fuji, STF from Sony or Loawa, or DS from Canon, than lenses without such elements. 

You can easily verify this in side by side images with the Fuji 56mm f1.2 and Canon RF 85mm f1.2, as both are available with and without such elements.

Fuji 56mm f1.2:
https://ivanjoshualoh.files.wordpress.com/2014/12/a01.jpg
Canon RF 85mm f1.2:
DS:
https://downloads.canon.com/nw/learn/launches/2019/may/articles/two-powerful-canon-portrait-lenses-rf-85mm-f12-l-usm-vs-the-rf-85mm-f12-l-usm-ds/Sample_image_RF851.2DS.JPG
non-DS:
https://downloads.canon.com/nw/learn/launches/2019/may/articles/two-powerful-canon-portrait-lenses-rf-85mm-f12-l-usm-vs-the-rf-85mm-f12-l-usm-ds/Sample_image_RF851.2.JPG
DS:
https://petapixel.com/assets/uploads/2020/03/APB10266-800x533.jpg
non-DS:
https://petapixel.com/assets/uploads/2020/03/APB10251-800x533.jpg

Hello Brightcolours,

first I will out me as the previous owner of mst's 50 f1.0... I still own the 56APD, a Canon EF85 f1.2 (not RF) and do mostly portrait and shootings.

Before I bought the APD I did a test shooting with a borrowed non-APD 56. That was actually some time ago already.
The "gain" of depth of field is in my opinion highly theoretical. I couldn't make out any differences in my tests, and when I look very closely at the photo you provided (56mm comparison), I don't see that either. What I can clearly see is the much smoother "edges" in the bokeh, a property of the lens that finally convinced me of buying one.

Concerning the brightness, the f1.2 of the APD are considered a f1.7 of the non APD-version, this much I can confirm, either the ISO is higher or the shutter is longer for the same photo. But when you turn the non-APD to f1.7, the DOF is less shallow than that of the ADP-version at 1.2, but that is barely noticeable. The AF in very low light situations suffers also a little bit from the "f1.7", at least on the X-T2.

And then came the 50 f1.0. I had the (in hindsight very optimistic) hope that the DOF would be noticeably more shallow. It is, but not to an extend I hoped for. It's fast, good AF performance, it's sharp. It's heavy, it's expensive.

So I bought an almost new EOS RP for my EF85, that's only slightly bigger and heavier than the XT-4/50mm, with very shallow DOF and the creamiest bokeh. The money for this combination is about the same then just for the Fuji lens alone. This combination is my stay-in-the-studio-"portrait gun" now, for everything else I use Fuji.

All in all, I had to learn again what I already learned before, full format is full format is full format ;-)

-Georg