The EOS 1D Mark IV hasn’t seen many updates in its time, and is just now being shifted up to firmware version 1.1.1. The update is purely preventative in nature and simply improves accuracy with soon to be released Canon 24mm and 28mm lenses.
To download the software, visit the EOS 1D Mark IV, select your operating system and then select the firmware update. Canon says that without the update, photographers using the new EF 24mm f/2.8 IS USM and EF 28mm f/2.8 IS USM may be left with overexposed photos.
