Add to the K135/2.5 pool here.
Generally fast, not very expensive, reasonably sized for the isolation they can give for portraits.
Coupled with the still reasonable size of this lens, I find that its perhaps the best compromise between portability/encumbrance as well as having a full body portrait focal length and mid reach lens for landscapes (on FF).
comparing the prices of k135 f2.5 against the A*135, i really think that k135 is really a value for money lens..sharpness is good on this lens and i am sure it will shine on ff..however, this remain the only lens which i had bought and sold twice..the first time i bought it..i regretted and bought it again..however having already the DA*50-135 and with no ff in sight then, i decide to sell it again the 2nd time..with the potential launch of ff, i think this lens will likely to see a comeback in demand..hopefully Pentax/Ricoh will update this lens with auto focus
IMGP7666 by Unforgiven28, on Flickr
28 by Unforgiven28, on Flickr
7 by Unforgiven28, on Flickr
26 by Unforgiven28, on Flickr
23 by Unforgiven28, on Flickr