Sorry about not getting back sooner with this reply. I have the vivitar version of the samyang lens, but other than cosmetics they are the same. The lens works well with the AFA adaptor, and is a great weight savings over carrying my K135/2.5 as well when city bound, BUT the AFA is very expensive, more than the 85/1.4 typically. The reason I used it is because I already had the 1.7x AFA. I have had this since I got my PZ1 in 1991, so for me it was a no brainer, so to speak. I would not get the AFA solely for this purpose, but if you also have a K300/4 and want limited AF with that lens

Hi Lowell, I´ve read some old posts about using a 85mm Rokinon with the Pentax AFA 1.7x. I am thinking of buying the rokinon with this porpuse. Could you share your thoughts about it? Samples maybe? Thanks, Francisco