Originally posted by thoughton Yes, absolutely, but what people in this thread are saying is that you can get as good or better results for less money with a Sigma or Tamron. Considerably less money in the Tamron's case. The only thing you lose is weather sealing, which for many people (who don't enjoy or spend much time out in the rain) this isn't a major issue.
I absolutely agree - which is why I linked to the PF comparative review earlier in this thread.
If you don't need weather sealing then the Tamron or the Sigma both seem to be excellent choices. That was the point the OP was making.
If you do need weather sealing then the Pentax 16-50 is a good lens.
The day I was at Suomenlinna, Helsinki it absolutely persisted down with rain most of the day (in fact the whole weekend was like that). Suomenlinna is a UNESCO World Heritage site and well worth the visit - the day I went was the only day I had available to go there. It is times like that - when travelling on tight schedules, that having a WR lens is the difference between taking photos or not. I was very pleased I had the 16-50 with me that weekend.
I brought the 16-50 specifically to cover a range of scenarios when travelling internationally on tight schedules. I only take one small Crumpler 5 bag with the K5, 16-50, 55-300 and a couple of limited primes. I never have space to take a big bag of photo gear, plus it adds considerably to the hassle factor.
So, it comes back to what do you need the lens for - my DA*16-50 works for me