The K-01 and Kiron 28 have arrived. The 28/2 is quite impressive, and that just sent the smc-M 28/2.8 packing. Even at f/2 it's quite sharp and contrasty, and the K-01's focus peaking means I can actually focus the thing where I intend. If wide open is good it means I can use aperture-priority setting rather than going Manual and hitting the green button to meter, which is a speed boost I can use at times. Like all lenses past the age of 20 or so, it's not perfect: the coating allows for plenty of flare to leak into the image from bright light sources, which affects the contrast at times. It's not ideal in a dark room with bright windows, for example.
I also attached the 28-80 Sigma from days past, with 1:2 close focusing. So far so good with results there too, no surprise as I have owned this lens before a few times (both 28-80 and the Quantaray 28-90 variant). Each time I've been impressed, yet budget forces a sale sooner or later. Maybe those days are past - but this one cost $28 even with the K-1 now available to absorb all full-35mm lenses.
So the K-01 can now rest in its 'cabinet' (2 shelves in a closet) and meet the other K-lenses in the group. Those include the 100-300 Sigma DL, 80-200 JCPenney and primes from the 28 Kiron, 50-100-135mm Pentax, 300mm mirror and 400mm Hanimar. Should be fun!