Thank you for using Canon products.
To Users of the EF300mm f/2.8L IS II USM Interchangeable Lens for Digital SLR Cameras
EF300mm f/2.8L IS II USM
It has been confirmed that some EF300mm f/2.8L IS II USM lenses (released in August 2011), when used with the Extender EF 1.4x, Extender EF 1.4x II, or
Extender EF 1.4x III, may exhibit back focus.
Affected Product: EF300mm f/2.8L IS II USM with the following serial numbers:
8210000089, 8210000436, 8410000443, 8520000035, 8520000068, 8520000078, 8520000079
8520000086, 8520000110, 8520000163, 8520000167, 8520000183, 8520000190, 8520000195
8520000217, 8520000289, 8520000295, 8520000311, 8620000036
The Canon Lenses affected by this phenomenon will be inspected and repaired free of charge. If you own one of the affected lenses, please contact our Customer Support Center.
This information is for residents of the United States and Puerto Rico only. If you do not reside in the USA or Puerto Rico, please contact the Canon Customer Support Center in your region.
Please register your EF300mm f/2.8L IS II USM. By registering, we will be able to notify you via email when future firmware updates become available for download. If you already registered, please ensure you are opted-in to receive the notification.
Customer Support Operations
Canon U.S.A., Inc
|Contact Information for Inquiries|
|Canon Customer Support Center|
|For additional support options: www.usa.canon.com/support|