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Firmware Notice: EF 400mm F2.8L IS III USM: Firmware Version 1.1.3.

Firmware Version 1.1.3 incorporates the following enhancement:

Focusing performance has been improved when using the Servo AF continuous shooting mode.

Firmware Version 1.1.3 is for lenses with firmware up to Version 1.1.2. If the lens’ firmware is already Version 1.1.3, it is not necessary to update the firmware. You can check the firmware version of the lens from the camera menu. Refer to the camera instruction manual for how to check the version.


Download Firmware Version 1.1.3 for the EF 400mm F2.8L IS III USM.

If you have not already done so, please register the EF 400mm F2.8L IS III USM STM. By registering, we will be able to notify you via email about future announcements.

This information is for residents of the United States and its five territories only. If you do not reside in the USA or its five territories, please contact the Canon Customer Support Center in your region.

Thank you,
Customer Support Operations
Canon U.S.A., Inc.

Contact Information for Inquiries
Canon Customer Support Center
Phone: 1-800-OK-CANON / 1-800-652-2666
TDD: 1-855-270-3277
Email: carecenter@cits.canon.com

Support options and hours of operation: www.usa.canon.com/support

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