Canon EOS-1D Mark IV Firmware Update 1.1.1
Canon has posted a firmware update for the EOS 1D Mark IV digital SLR camera. Version 1.1.1 optimises the camera’s exposure accuracy when using the Canon EF 24mm f/2.8 IS USM and EF 28mm f/2.8 IS USM lenses, which are scheduled for release in June 2012. If these lenses are used with a Canon EOS-1D Mark IV camera that has not been updated with the new firmware, the image may be overexposed depending on the subject and shooting scene. You can download the firmware update from the website below.
Website: Canon EOS-1D Mark IV