Originally Posted by Rmspar72
This my first post here..I have a K10d and 18-55 of course the kits lens...I will be purchasing the Pentaz 50mm 1.4 for sure ....any opinions here for the Pentax 17-70 F4 zoom verses the Sigma 17-70 2.8? I read the reviews for both & like the Sigma from a price perspective but would be open to the pentax if there is a big difference in quality images....thanks for any feed back...

Robert
I'm using the Sigma in preference to the Pentax kit. There are two reasons:
The larger aperture of the Sigma allows me to shoot indoors more often without flash. Available light makes me happy.
The longer reach at 70mm means that I can avoid a certain number of lens changes. I have found a lot of occasions, like family gatherings or in museums, where I will use anything from 17mm to 70mm in the space of a few minutes. I found the kit lens kept me yearning for just a little more reach.
At my level of ignorance, I'm paying more attention to composition and exposure than I am to IQ, CA, etc. I'm willing to give up a bit of quality here and there to get ease of use.
Does that help??