I have seen conflicting information about the compatibility of the PC 19mm with the Nikon Df.
This page:
http://www.nikon.com/news/2016/1019_lens_01.htm says: "When used with cameras other than the D5, D4 series, D3 series, D810 series, D500,
or Df (emphasis mine), some combinations of shift and rotation may not be possible due to the fact that the lens comes into contact with the camera body."
But this page
http://www.nikonusa.com/en/nikon-products/product/camera-lenses/pc-nikkor-19mm-f%252f4e-ed.html from the Nikon USA website says: "Usable models although there are some limitations:
Df (emphasis mine again), D800 series, D750, D700, D610, D600, D300 series, D7200, D7100, D7000, D5500, D5300, D5200, D5100, D5000, D3400, D3300, D3200, D3100."
Do you know which information is right, and as the case may be, what are these limitations?