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Details

Firmware Version 1.3.3 incorporates the following improvement and fix:

Improves the AF controllability when shooting in Live View mode with a wide-angle lens (fixed focal length or zoom).
Corrects some incorrect indications on the “English” and “Russian” menu screens.
Firmware Version 1.3.3 is for cameras with Firmware Version 1.2.3 or earlier. If your camera's firmware is already Version 1.3.3, it is not necessary to update the firmware.

When updating the firmware of your camera, please first review the instructions thoroughly before downloading.

Note:
Once the EOS 5D Mark III camera is updated to Version 1.3.3, it cannot be restored to a previous firmware version (Versions 1.0.7 through 1.2.3).

Support

Download Firmware Version 1.3.3 for the EOS 5D Mark III Camera

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.

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