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To the Users of the EF300mm f/2.8L IS II USM, EF400mm f/2.8L IS II USM, EF500mm f/4L IS II USM, and EF600mm f/4L IS II USM Interchangeable Lenses for Canon Digital SLR Cameras
UPDATE:
Please see the changes to the “Identification Procedure” section below regarding the criteria for affected serial numbers. The identification procedure has been enhanced to include the first, second and third digits from the left in order to more precisely identify affected products.
Thank you for using Canon products.
Canon has released a firmware update for EF300mm f/2.8L IS II USM, EF400mm F2.8L IS II USM, EF500mm f/4L IS II USM and EF600mm f/4L IS II USM lenses. This firmware update will be performed by Canon Service Centers. Please contact us using the contact information listed at the bottom of this page.
Firmware changes:
Firmware Version 1.1.1 incorporates the following enhancement:
1. Changes the control algorithm of the focus drive, and enhances the drive’s responsiveness for more precise
focus and adjustments. In particular, the new firmware enhances the AI servo AF capability of the lenses
to track objects that move irregularly in sports events, such as soccer or rugby.
Affected Products:
Firmware Version 1.1.1 is for lenses with Firmware Version 1.0.0. If the lens’ firmware is already Version 1.1.1, it is not necessary to update the firmware.
Identification Procedure:
The first, second, and third digits from the left in the serial number (10 digits) for lenses equipped with Firmware Version 1.0.0 are as follows:
| Lens name | Serial numbers of affected products (x presents any optional numbers) |
| EF300mm f/2.8L IS II USM | 790xxxxxxx through 913xxxxxxx |
| EF400mm f/2.8L IS II USM | 790xxxxxxx through 913xxxxxxx |
| EF500mm f/4L IS II USM | 880xxxxxxx through 910xxxxxxx |
| EF600mm f/4L IS II USM | 880xxxxxxx through 910xxxxxxx |
Lenses with serial numbers other than those listed above are equipped with Firmware Version 1.1.1 or later.
Support
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, EF400mm f/2.8L IS II USM, EF500mm f/4L IS II USM or EF600mm f/4L IS II USM. By registering, we will be able to notify you via email when future firmware updates become available.
Source: [CUSA]
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