Originally posted by frogfoot This is what I call unusable. Comparison between 18-135 and 50-200: 100% crop of right lower corner.
BTW at wide to middle range my 18-135 is noticeably sharper and more contrast than 16-45 (I'm talking about center. Corners are still weaker). So I don't know if my lens can be called faulty.
P.S. After more careful examination I can say that 18-135 is not worse than 50-200 in the range of 50-100 mm.
Well that's exactly the type of image I get too, see my link above. Wide open at 18mm I can get the same soft corners but then it depends on the scene (field curvature?) It's not motion blur. I see this from about 80mm and up on the corners and above 100mm also the center gets less sharp than on the DA50-200 and quite some CA appears.
But from 50 to 60mm my DA18-135 is much better than my DA50-200. From 18 to 70mm it mostly beats my 18-55/50-200 combo when stopped down so it's probably a keeper. For the good teleshots I will take the DA50-200 (or I'll buy the DA55-300) with me but I will have to switch much less often.
Most reviews mention this behavior so my guess it's the design of the lens, or there are more bad than good copies..