After much diligent searching on Ebay and elsewhere , I tracked down a used Hartblei 45mm tilt/shift for my 645Z. I had been researching the comments/reviews/reports on a variety of sites , and, frankly, was in two minds about buying one, as the comments varied between the good, the bad, and the ugly!
However my initial experiences are positive , and providing you follow the recommendations Stefan Steib reported elsewhere in this section (
https://www.pentaxforums.com/forums/48-pentax-medium-format/273881-645-tilt-s...#ixzz4Jw26EqF7), the resulting image quality is very good....of course it is not an 'easy' lens to operate by modern auto-focus standards, as it is entirely manual and therefore slow to set-up and use....you also need to focus 'very' carefully using magnified Live View to ensure everything you expect to be in focus , is in focus......
The controls on the lens are very smooth , and much easier to operate than I expected, although great care is needed to ensure you don't alter focus or f/stop when rotating or shifting the lens , for stitched panos...
My initial tests have been interior shots of no artistic merit at all, but sufficient to see that image quality is very good, albeit not to the standard of the newest DFA Pentax Z lenses (90mm , 55mm and 28-45mm) or best ones of the older FA series.
Assuming there is now no significant variation in production quality, and that you can find a clean example of the current (newer 'Digital' branded) version, the Hartblei 45mm F 3.5 t/s is a good addition to the lens arsenal for the 645Z. I will post some images when I have done more landscape/cityscape work, and also plan to test it on some fashion subjects.