Pentax Adapter Q. All shots handheld (the macro shots were on a table and I was able to use that for support), available light. I didn't make note of the aperture settings, but from memory the first two would have been at setting 1.5 or 2 (i.e., f/4.5 or f/5.6) and the macro shots at setting 0.5 (i.e., f/3.5).
50% crop Moderate crop 1:1 macro, 4 shots stacked in Zerene Stacker (PMax retouched from individual shots), uncropped
The pale yellow spot on the spider's head is an individual grain of pine pollen
Conclusions: certainly a good performer on the Q both as a telephoto and an extreme macro lens. Some CA but I have done no correction for it in the shots here, and it isn't bad. It's a fairly large and heavy lens for handheld use on the Q. For macro keep in mind that at high magnifications the effective f-number goes up; a good approximation is f(effective) = f(nominal) * (1+magnification), so at 1:1 the f-number is effectively doubled. Which is to say, for shots above 1:2 or so, use a smaller f-number.
Edit: Some testing in a studio setup (tripod, SR off) shows f/4 (setting 1.0 on the Pentax Adapter Q) as the best aperture at 1:1 magnification.