Originally posted by Mr Spocko Paul has a point, optics wise it's performance is more kit lens like than pro grade zoom lens. Whatever way you cut it if the review samples are a fair reflection on most copies it's very strange because to design a good lens with such a short range isn't exactly that hard for any lens designer. There is little point beating on about how nicely it's made if the performance isn't reflective of the price paid.
For the money nothing short of stellar is acceptable for such a lens.
Again, I don't have a problem with the review but to claim that this lens can not produce a sharp contrasty image at 40mm until f8 is not reflected in every other user who has taken the time to type out their own user review. I can say that if I had the image resolution issue that Adam's copy had, I certainly would have sent it back. And though I can't speak for others, I suspect, having spent nearly $1,000 for the lens they would do the same.
Having shot thousands of images with my DA 21, 35ltd. and 40, I can say without having the imatest data in front of me that this lens produces sharpness, clarity and color that is the equal of the primes and more so...and it has WR to boot. It sounded like Ogl had done some testing so there is perhaps data that would support my assertion. Bottom line for me, if I add up the cost of those 3 lens purchased now I'm looking at over $1500 so to me the 900 for the DA ltd. zoom is a fair price. Your mileage my vary.
There are lots of options out there including used $250 Tamrons. If you don't like what Pentax has to offer great go for something else. But I do find the shock and horror that Pentax didn't produce a Sigma clone (with "Pro Specs") interesting. I haven't been shooting Pentax for as long as many other on the forum but the DA ltd. zoom was exactly what I'd expect from Pentax. They offered a compelling solution to those out there who want the DA prime quality and aesthetic but don't want to change lenses.