Originally posted by Genshu Holy Toledo, I just looked through the Tammy club shots and my jaw dropped at the sharpness. I really want one now! Have to say that I am attracted to the wide angle shots, causing more indescision. this problem with the 17-50 sounds like a deal breaker though. any thoughts about an alternative for the 17-50?
Even with the aperture problem, the Tamron 17-50mm is still a good lens, and for the price it's hard to beat as a direct replacement for the kit lens.
As far as an alternative, Sigma just released a new 17-50mm f/2.8. The few reports I've read of it are very positive, and it appears to have better image quality than the Tamron.
Another big advantage is that it has a silent and fast HSM focus motor, whereas the Tamron uses the screw-drive for focusing.
And the Sigma even has OS. Probably kind of redundant since Pentax has stabilization in the body, but Sigma's OS is supposed to be very good and may out-perform Pentax's OS. It would also allow you to see the effects of stabilization when looking through the viewfinder, which might be nice.
The only bad thing is that the Sigma costs about $200 more than the Tamron. The Tamron sells for around $460, while the Sigma is selling for $670.