Canon Japan has today announced that a firmware update, version 1.1.1, will be (or has been) released for the following lenses:
Canon EF 300mm f/2.8L IS II USM Lens
Canon EF 400mm f/2.8L IS II USM Lens
Canon-EF-500mm-f-4-L-IS-II-USM-Lens
Canon-EF-600mm-f-4-L-IS-II-USM-Lens
Firmware Version 1.1.1 will incorporate the following improvements
The control algorithm of the focus drive has been updated to improve the responsiveness of fine focus. Canon has improved the capability of the specified lenses to track irregular movements, such as soccer and rugby in particular in AI Servo AF mode.
Included Lenses
Lenses with a firmware of version 1.0.0 are the target of the version 1.1.1 update. These lenses can be identified by their 10-digit serial number as follows:
EF300mm F2.8L IS II USM and EF400mm F2.8L IS II USM:
A third digit of "0", "1", "2" or "3" - xx0xxxxxxx, xx1xxxxxxx, xx2xxxxxxx, xx3xxxxxxx)
EF500mm F4L IS II USM and EF600mm F4L IS II USM:
A third digit of "0" - xx0xxxxxxx
Products other than the above already have firmware version 1.1.1 installed.
To Have Your Lens Firmware Updated
Direct Google translation: "Available to those customers, we ask that you please bring to office repair the firmware update. In addition, it will be working on your deposit, you will get time of about one week. Please be patient."