Originally posted by stevebrot I would assume that neither the PRIME engine nor the AF controllers are other than in-house efforts. Both tend to be highly proprietary and, I suspect, not derivative.
Edit: As noted above, the main processor for Pentax cameras is Milbeaut with that product defining many of our camera's features and limitations...unless overridden, of course, by specialty chips. Where the critical guts of "Prime" lives is hard to say with any certainty without a full dissection of the innards. It is a fairly certain guess that things like the exceptional AF of the Nikon D500 are not the result of tweaking off-the-shelf capabilities from Socionext.
Steve
It is well-known that Nikon has a separate special processor which does the focusing for the D5, D500, D7500{maybe}, and D850 .... in other words, for the cameras that have especially good Auto Focus. Most Nikon cameras don't do nearly so well on high ISO - despite their reputations - I've been told flat-out by Nikon users that the D500 has noise issues, and none of them test as well as the K-1 does. Clearly Pentax is concentrating on Image Quality .... is everyone here salivating over what Nikon does but Pentax doesn't, instead of enjoying what Pentax does but Nikon doesn't???
Look at the DxOMark sports ranking, which is actually a low-light ranking.
https://www.dxomark.com/cameras/brand-nikon-pentax/launched-between-2002-and...taType=rankLln
The K-1 is 8th among all cameras, closely followed by the 16mb Df. The D750, considered by Nikon users to be their best camera for low-light, is 19th, and the mighty D850 is 26th.