17-55 focus problems

[sambisu]

I just did some autofocus testing on my 17-55 f/2.8 because I was getting a lot of images with the focus just slightly off. I printed off a test pattern and tested the lens at f/2.8 by taking an image focused in live view and comparing it to an image auto-focused normally (using center point).

100% crops of test images are below. I also tested with the same setup using 2 other lenses (70-200 f/2.8 IS II and the 18-55 kit lens) and saw no discernible difference between the images. The autofocus appeared dead on for those lenses, which leads me to believe there is no issue with my camera. So my question, is how should I go about getting this fixed? Just send it to Canon (and if so, any idea of how much this costs)? I bought the lens used off eBay about 2 years ago.

https://farm6.staticflickr.com/5595/15049057315_db7f9a83f4_o.jpg (https://flic.kr/p/oVQmrr)20140826-1447 (https://flic.kr/p/oVQmrr) by sambisu (https://www.flickr.com/people/79295264@N04/), on Flickr
https://farm6.staticflickr.com/5578/15049057415_87da43bd95_o.jpg (https://flic.kr/p/oVQmta)20140826-1446 (https://flic.kr/p/oVQmta) by sambisu (https://www.flickr.com/people/79295264@N04/), on Flickr

[Sean Setters]

If you are getting consistent AF results like this using the EF-S 17-55mm f/2.8 IS USM, then it looks like you need an autofocus microadjustment. However, if using the T2i, your camera does not have that feature. Therefore, a trip to Canon's Service Department will be required to adjust the lens to your specific camera body.

[sambisu]

These results were consistent. I tested multiple times and at various focal lengths. So would I send in the camera along with the lens?

[DavidEccleston]

And, as all your other lens are fine, mention you want the *lens* adjusted, not the body. :)

[sambisu]

Thanks. A little painful to spend over a quarter of the price of a new copy of this lens just to get it focusing properly. Sure would be nice to have that microfocus adjustment feature.

[neuroanatomist]

Thanks. A little painful to spend over a quarter of the price of a new copy of this lens just to get it focusing properly. Sure would be nice to have that microfocus adjustment feature.

That was a big reason for my switch from T1i to 7D...

[sambisu]

Yea I suppose this would be an opportune time for an upgrade to a body with that feature, but I'm saving up to go FF.