Originally posted by tomsparks So, I am a week away from buying a new lens and I'm debating the Pentax 50-135 vs Sigma 70-200. Why did you go with the pentax over the Sigma?
I was looking at a 70-200mm as well (the Tamron though). Couple things made me go for the Pentax. Weatherseal was a feature I liked; although the DS I use isn't, when I eventually upgrade to a K20D (or higher model in the future), I'd like the complete package since I tend to shoot in dusty and other less than ideal camera conditions.
Motorsports was the reason for me wanting a high quality telephoto zoom ... and although the 70-200 focal length is suited well for that, I decided for the 50-135 because I was able to pick up a brand new Tamron 1.4 TC. Combined with the 50-135, it would give me a similar focal length to the 70-200. The loss of 1 stop isn't too much of concern for me and I know IQ is still very good from several samples I've seen on the forum.
And, shooting with the DA*300 the past few weeks, I guess I got spoiled by the quality of photos the DA*'s can produce. Seeing various samples from other owners of the 50-135 only made me want the lens that much more.
I guess it comes down to whether the focal range suits your style. If you
really need that extra reach, go for the Sigma. Whichever lens you decide on, both are great lenses from what I've seen. Good luck with your decision!