Originally posted by slip IMHO if you can get a used either Sigma or Tamron 70-200 2.8 it would be a step up. I have an older Sigma which is soft wide open but when stopped down to F4 works well. it's fast focusing compare to most of the comparable Pentax lenses. if money was no object the D FA 70-200 2.8 would be the ultimate lens as far as quality and flexibility
good luck
Randy
I was able to get my Tamron 70-200 2.8 for $500 last year at KEH. It is my favorite lens for many things, but, I can't use it without a tripod. It's too heavy for me otherwise. That said, I do find the combination of 18-135 and 55-300 to be a great go anywhere kit. I also vote for the 55-300 for what you are doing right now.