UPDATED: Hasselblad X1D ISO Series from 100 to 25600
See my Hasselblad X1D wish list and Fujifilm GFX wish list.
In my review of the about $8995 Hasselblad X1D in my new medium format section I have updated the ISO series page with a full RawDigger histogram series and commentary, discussing the curious behavior starting at ISO 6400 (scroll to end).
Hasselblad X1D ISO Series from ISO 100 to ISO 25600 (Dolls)
Definitely worth a read for high ISO shooters. I am finding similar behavior with the Fujifilm GFX.