Firmware update for Canon 300mm, 400mm, 500mm, and 600mm L IS II lenses

Canon has released a new firmware update (Firmware Version 1.1.1) for the EF 300mm f/2.8L IS II USM, EF 400mm F2.8L IS II USM, EF 500mm f/4L IS II USM and EF 600mm f/4L IS II USM lenses. This firmware update will be performed by Canon Service Centres.

The products affected by this issue will be updated by Canon free of charge, just contact one of your authorised service facilities.

Firmware Version 1.1.1 incorporates the following enhancement:

• Changes the control algorithm of the focus drive, and enhances the drive’s responsiveness for more precise focus 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. Please contact Canon customer support if you are unsure as to what firmware your lens currently supports.
The serial numbers (10 digits) of the lenses equipped with Firmware Version 1.0.0 are as below.
EF 300mm f/2.8L IS II USM:
The third digit in the serial number is either 0, 1, 2, or 3 (xx0xxxxxxx, xx1xxxxxxx, xx2xxxxxxx, xx3xxxxxxx).
EF 400mm f/2.8L IS II USM: The third digit in the serial number is either 0, 1, 2, or 3 (xx0xxxxxxx, xx1xxxxxxx, xx2xxxxxxx, xx3xxxxxxx).
EF 500mm f/4L IS II USM:
The third digit in the serial number is 0 (xx0xxxxxxx).
EF 600mm f/4L IS II USM:
The third digit in the serial number is 0 (xx0xxxxxxx).