Update! Just published in my review of the Pentax 645D in Medium Format is a new page on the Pentax-A 120mm f/4. More will be added over the next few days, but in short, the Pentax-A 120mm f/4 is easily the best lens I’ve yet used on the 645D, by no small margin. I refer to the manual focus version, I have not seen or tested the FA version.
I do very little macro work, but I thought I’d try the Pentax-A 120mm f/4 macro on the Pentax 645D. Here, handheld at ISO 1600, is a matchbox cover measuring 32mm across (I cropped off about 1mm). This is at 1:1 reproduction, since the Pentax sensor is 33 X 44mm.
The matchbox is slightly bowed (not perfectly flat), and this was handheld as best I could, but I’d say sharpness is looking very good at close range. ISO 1600 certainly has done very nicely here. (Note that this isn’t a test so much as a picture I liked).