Howdy. Just bought my K-5 a month ago and have recently upgraded my kit lens to the Sigma 17-70 f/2.8-4. I debated for awhile between the Tamron 17-50 f/2.8 and the Sigma 17-70 because they were in my price range.
I've had the Sigma for about a week and I have found the image results to be not what I expected from an update to the kit lens. To add insult to injury, I just tested the lens creep and it looks like whenever I set the length to 50mm and tilt it vertically, it will smoothly drop to 35mm.
The build quality of the Sigma is great but I didn't expect this. Has anyone else experienced this?