It's a long-standing problem that most people live with. If you're feeling adventurous, I have heard this solution actually works:
"There is another way that is a little bit more invasive.
Slide the rubber from the focus ring towards the mount of the lens (not the zoom ring). It's not glued and comes off easily. Rotate it until the hole matches the screw, there should be 3 around the lens. Simply tighten them but be very careful it's very easy to go over and chew the thread."
Mine doesn't creep (yet) so I haven't had to fix it.
Thank you guys. I have an extended warranty that is from the store I bought the camera kit (not from Canon)
I took the lens to Canon and this is the reply:
"After inspected by our technician, they confirmed that the elasticity of the zoom barrel of this lens is under normal performance, if you need it more tight, we could replace the zoom barrel and some bigger collars on it(with charge HK$1292).
Kindly refer to the attached quotation for your further consideration."
Then I asked: "Could you please explain why if the elasticity of the zoom barrel of this lens is under normal performance the barrel creeps down"
Answer: "With regards to your concern, please note that the holding structure of the zoom barrel is assemble with the collars, and the collars condition may affect the zoom barrel tightness. In general, collars ageing issue is the most common problem which affected the zoom barrel performance.
Therefore, you may consider to replace the zoom barrel and collars in order to improve the problem that you have raised. Please reply to this email to let us know about your decision, so than we may follow accordingly."
I: "Would this issue be covered by the warranty if the lens was still under warranty?"
I don't know if the shop extended warranty will cover the expenses but I will definitely check. If not I'll live with it but its annoying...
I'd have a go at the technique that Robert posted. It's very likely that you can alleviate the issue at least in the near term. It might crop up again later, and eventually you might not be able to adjust it out, but it may be a long time before it reappears. If you do it, start with *very* small adjustments. You should be able to check the results without even re-seating the rubber ring.
