Originally posted by glengood would you pay $90 more for the 17-70mm lens over the 18-50mm ?
Thanks!
Yes. Amongst these two, the 17-70 is the better optical choice.
The Pentax 18-135 is about the same optically as the 17-70, but has WR and goes to 135. However, from 70 to 135, the optical performance drops off some, so it's really more like a very good 18-70 with an OK 70-135 added on. The Sigma 17-70 focuses closer, so better for macro-type close ups.
If you are an outdoorsy type of person, get the 18-135, if you don't think you need to take pictures in the rain, get the Sigma 17-70. I thought WR was not important to me, until I was on vacation in a storm, and got to keep taking pictures.
On the other hand, you could get the 17-70, and get the 18-55WR for those days, but then you'd have just about the same money invested as the 18-135.