The problem affects all EF24-105mm f/4L IS USM lenses with a control number less than UT1000. With apologies for the inconvenience involved, we ask customers to check the control number on the back of the lens.
Affected model and control numbers:
EF24-105mm f/4L IS USM
The control number is indicated on the back cover of the lens with UTxxxx symbol (see the number in the red ellipse on the right), and if it contains the letters UT followed by a number under 1,000, the product is affected. Should you have any difficulty identifying the control number, please contact our service centers.
The number on my lens doesnt have the prefix UT, but, UU0404. I am not completely familiar with the way Canon numbers their lenses. Am I ok?
Maiznblu_757 From , joined Dec 1969, posts, RR:
Reply 2, posted (9 years 3 weeks 1 day 16 hours ago) and read 4821 times:
Thanks, I just called and spoke to someone from Tech Support. Sadly, the guy I spoke to had no idea. SO he placed me on hold for about 10 minutes. He came back and said anything after UT is good. I asked him "For future reference, how does the number/letter system work?" He said "I couldnt tell you". Oh well, at least I am 100% sure I have received a good lens.
Dehowie From , joined Dec 1969, posts, RR:
Reply 4, posted (9 years 3 weeks 1 day 9 hours ago) and read 4770 times:
You are fine mate.
The UT part refers to the factory of manufacture and i cant remember but i think there may be three different centres.
There is an article on reading the numbers at Fred's.