Took 11, 000 pictures with this lens, then suddenly it had a communications failure with t3i. this is a known defect with this lens -- i.e., the flexible cable inside the lens that does the electronic communication wears out and fails. The lens then stops working completely. The lens was bought in 2012 and failed after 18 months (out of warranty of course).
That it failed on a trip to an african country was very disconcerting. Fortunately I had an EF 35mm 4L, an EFS 10-22mm, and an EF 70-200 mm 4L with me.
Will probably either get it fixed (have Canon replace the cable) or buy an EF 24-70mm 4L for a more dependable lens...having a lens fail on a trip is untenable. Such a product with a known defect-- particularly given the fact this lens was bought 4 years after it was introduced by Canon just shouldn't happen!! The defect should have been corrected within 2 years of its introduction.
January 3, 2014
Poor quality and poor performance
The autofocus failed during a trip at the Everglades, I had to work on manual mode all the time. The repair is a very difficult task and costly. I has the lens for over two years, Canon should stop advertising this lens.
December 24, 2013
Defective design - do not buy
This lens failed when I went to the galapagos. Good thing I had a backup, since having no wide angle would have been a big problem. Came home to find out these lenses are simply bad and wear out. Unreliable autofocus past 18mm means the lens isn't worth much. Buy something else.
July 10, 2013
I have had this lens for 5 years and before I bought it I was hesitant because of some bad reviews. My copy of the lens has been great. I have never had a problem and the pictures are razor sharp. I use it on a Canon 50D and T2i. It also focuses fast.
May 13, 2013