With the 12-24mm's huge DOF it's surprising that your shots seemed soft. In any case, here's an article that tells you how to test your lenses:
Fixing Front and Back Focus - Introduction - PentaxForums.com
If possible, I'd also suggest you post some pics here on the site so we can try to discern the problem.
Adam
PentaxForums.com Webmaster (
Site Usage Guide |
Site Help |
My Photography)
PentaxForums.com server and development costs are user-supported. You can help cover these costs by
donating or purchasing one of our
Pentax eBooks. Or, buy your photo gear from our affiliates,
Adorama,
B&H Photo,
KEH, or
Topaz Labs, and get
FREE Marketplace access - click here to see how! Trusted Pentax retailers: