The Canon EF 400mm f/2.8L IS III USM is a professional super-telephoto prime lens offering exceptionally fast f/2.8 aperture for superior subject isolation and low-light performance at 400mm. It is significantly lighter than its predecessor through extensive use of magnesium and titanium construction, making it Canon's lightest 400mm f/2.8 at release. Firmware updates maintain compatibility with the latest Canon camera bodies and AF systems.
Product released: September 1, 2018
Latest firmware version
Version 1.1.3, released July 7, 2020
What's new in version 1.1.3
Firmware Version 1.1.3 incorporates the following enhancements: ・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. Please review the instructions thoroughly before you download the firmware. Preparations for the firmware update: In the folder you downloaded are the firmware ( EF019113.lfu / file size: 2,883,636 bytes) and instructions on the firmware update procedures (a PDF file in five languages: Japanese, English, French, Spanish, and Simplified Chinese). Before starting the firmware update operations, please be sure to check the procedure in accordance with the instruction.