I am looking for all around lens to replace my kit lens (18-55mm). I have been busy shooting club photos, to save the money to buy a better lens. I now realize the importance of a quality low light lens, so the new lens needs to be F2.8 or better. I will be shooting portraits, some Architecture and eventually kids' soccer and softball portraits mixed with some actions shots.
I've been looking at Tamron 17-50mm and the Tamron 28-75mm, both are f2.8, but finding stores that sell the Pentax mount has been a challenge.
Can anybody suggest a store that doesn't sell gray-market lenses? And are these two good choices for my needs. How much better is the Tamron 17-50mm over my SMC 18-55mm kit lens?