The above notwithstanding, you won't go wrong with the very excellent DA 50 1.8 and DA 35 2.4. Inexpensive, lightweight but by all accounts they deliver outstanding performance regardless of cost. Are they in the same league as the 31 limited? Probably not. Will they give excellent images using the K-50? Absolutely. Were you a professional photographer looking for the absolute best performance regardless of cost the advice might be different but if you, like me, are an average Joe, looking to improve your results on a minimal budget then you are definitely on the right track.
---------- Post added 03-21-15 at 08:29 AM ----------
Originally posted by Sagitta Strangely, for me the 35 is my newest favorite length. I don't know if its the lens or the length, but I have a hard time keeping the 35 off the camera.
The 35 is a great walkaround lens for the APS-C format. I did notice the other day that the 50 is internal focus while the 35 is not but still the normal perspective of the 35 makes it more versatile for my uses. I have both and I expect both to get a lot of use... when I have a working body again with which to couple them, but that's a whole 'nother story.