8 out of 10 points and recommendedLens lock, non-rotating barrel, sharp center frame areaa bit slow (f6.3 @ 200mm), moderate vignetting, difficult to auto-focus in low light
I wasn't really sure what this 'walkaround' lens could offer at this price point; but, it performed fairly well.reviewed July 16th, 2007 (purchased for $330)
The metal base is a plus, and it's definitely the best choice 18-200mm lens for our Pentax K10D.
Face it, the vast majority of us won't be shooting test shots under controlled conditions in a studio, and looking for spectacular sharpness from edge to edge, without noticeable vignetting. So, don't get hung up on studio test shots when evaluating lenses.
After shooting several thousands of photos over the past two months, I have found the 'standard' of f8 through f11 to be the optimum aperatures across the entire focal range. No surprise there. But, you can still use a faster f stop with good results. Especially with the K10D which features a sensitivity shooting mode, and image stabilization is built in.
The great thing about photography technology these days is the excellent software packages that allow us to make key adjustments and compensations for distortion, vignetting, and sharpness issues for the shortcomings of 'budget' priced lenses.
If you're seeking absolute perfection, you'd better pass on this lens. But, if you want better than average results and can't justify forking over $750 to a grand for a comparable competitor's zoom lens, give this one a try.