EOS 5D Mark III Firmware Version 1.2.3
Firmware Version 1.2.3 incorporates the following improvements and fixes.
* Fixes a phenomenon in which the flash may not fire depending on the timing of when the shutter button is pressed.
* Fixes a phenomenon in which the AF microadjustment value may change.
*Fixes a phenomenon in which the LCD monitor may show a line of false color along boundaries of high contrast.
*Fixes a phenomenon in which the histogram of a LiveView image is incorrectly displayed when an HDMI cable is connected.
*Enables the brightness of the cameras LCD monitor to be adjusted even when an HDMI cable is connected.
*The phenomenon listed in 2 was addressed with Firmware Version 1.2.1, and has been further improved with Firmware Version 1.2.3.
Firmware Version 1.2.3 is for cameras with firmware up to Version 1.2.1. If the cameras firmware is already Version 1.2.3, it is not necessary to update the firmware.
When updating the firmware of your camera, please first review the instructions thoroughly before you download the firmware.