« on: July 27, 2011, 05:14:37 PM »
I already own a 17-40mm. After extensive testing and comparison I found it to do significantly better than the more expensive 17-55.Funny how I thought the same thing about the 17-40 vs 17-55 on my original tests...
Interesting - how was it significantly better?
I tried out a 17-40mm and definitely preferred the 17-55mm from an optical standpoint - especially stopped down to f/4, the 17-55mm is sharper across the frame, and the EF-S lens, surprisingly, has less barrel distortion at 17mm than the 17-40mm, despite a broader zoom range and the 'sweet spot' effect of using an EF lens on a crop body. The only place the L lens won was less vignetting. From a build standpoint, the L lens is definifely better, of course.
I ended up getting the 16-35mm f/2.8L II instead of the 17-40mm for use on FF (as good or better at comparable apertures), and the 17-55mm on the 7D outperforms the 16-35mm II on the same body, from my own testing. I shoot a fair bit of wildlife with the 7D and a telezoom, and bring a standard zoom along 'just in case' - in the rain, I bring the 16-35mm II, but otherwise I grab the 17-55mm lens, and in fact, I hung onto that lens after getting the 5DII for just that reason.
It's hard to say... when I did my testings I tested it against the sigmas and tokinas (my local store didn't sell tamrons so i couldn't test their version which has gotten good reviews) as well as each other... I dont know... I just felt when I did my unscientific tests, the 17-40 locked focus a tad faster, felt more robust (i need my gear to keep up and be ok if it has a little bang here and there)... the L had weathersealing and IQ i felt was close but not near enough to warrant the price difference. The 2.8 would have been nice but that wasn't a driving factor because I was ok with my cameras ISO if needed. For what I do and how I shoot, that's how I made my choice. BTW, the sigma and tokina lenses tested were horrid in focusing in low light. The 17-40 I was able to focus almost in the dark without even needing the AF lamp... I'm sure under certain conditions the 17-55 could produce sharper images but I've been pleased with my lens.