Excerpt: The reviews on this lens were not good 2 years ago as was the case with the 18 -135 also.It think it is asking to much of a lens to expect much in performance with such a wide range of barrel lengths.
Conclusion: When I purchased my EOS 7D, I chose a package which contained the EF 28-135 IS USM lens because I figured it would be better than the EF-S option and because I wanted to be able to use it when I upgrade to a full-frame camera. Fortunately, it wasn't too costly a mistake.
Excerpt: I bought this lens to match up with my Panasonic AC130 for 2 camera shoots. I can match it fine but the images are not sharp. I "punched in" with the magnify button endless amounts of time on my 6D and seemed to have it in focus, but it never really was even at f9.
Conclusion: Very poor quality in the range between 80 and 135mm, even for regular printouts. Very sensitive to sand and dust, barrel shaky. 24-105 L is so much better. If anyone considers buying a DSLR for reasons of image quality (over choosing a analogue or bridge camera), this lens is inadequate for the...
Excerpt: Have to use this lens with caution. It does not produce results like the "L" series lenses. It has a wonderful range of focal lenths, but it is a little bit of a compromise if you want sharp, sharp images. Great running around lens, but if you are serious about photography, and image quality.