My local B&M store had a "Sony Studio" day where a "Sony Ambassador" set up a one light studio and explained her technique ... I went to hands-on test an Alpha 7 or 7ii ... since a Sony Rep was there, too, with a lot of goodies like an Alpha 9 and Zeiss glass.
I took the K-1 and rapidly snapped a couple with the 77/1.8 of the young girl who was the model. First image is the K-1 at 100 ISO in front of a constant light soft box. And for fun, the second image is with an APS-C Sony Nex 5 + a Minolta MD 50/1.2 @ about f/4.
I took the MD 50/1.2 and its adapter to try it out on a full frame Alpha (7ii) and to be truthful I was not that impressed ... also tried the same Alpha 7ii with a G 24-70/2.8 and maybe it was me, but I found it to be pretty mediocre.
My interest in a Sony Alpha took a big dent today ... I am still quite convinced that I am quite good in Pentax.