Hi and welcome to the forum!
Great images; thanks for sharing!
Originally posted by Matthew Saville So, when you say "Auto Aperture" works fine, you mean that I can shoot in manual exposure or aperture priority, and set the aperture either on the camera or on the lens, and get the full EXIF info if I tell the camera what lens / aperture it is?
The Rokinon / Samyang / Bower lenses on Pentax are fully supported, i.e., matrix metering works, focus confirmation works, the f-ratio can be chosen on the camera body and is recorded in the EXIF data, etc.
The only limitations are that you have to provide the focal length manually upon start up (if you want to use the in-body image stabilisation with the lens) and you (obviously) have to manually focus.
BTW, the Samyang 85/1.4 is an exceptional lens.
P.S.: Do you know the Pentax O-GPS1, aka "astrotracer"? It goes on the hot-shoe and then enables the camera to track the movement of the stars by shifting and rotating the sensor. It also adds GPS data to the images, but I guess you are probably more interested in the "star tracking" capability.
Depending on the quality of the calibration, the O-GPS1 can achieve impressive results. Unfortunately, calibration quality seems to be a bit "hit and miss" sometimes probably caused by the fact that the compass has a hard time to find its bearings, but with a bit of luck you can get great results. Here's a
respective discussion about the merit of the astrotracer.