Canon has released firmware version 1.2.3 for the EOS 5D Mark III, which fixes four bugs (including one in which the flash may not fire when the shutter is pressed) and adds the ability to adjust LCD brightness when an HDMI cable is connected.


Canon has released a firmware update for the EOS 5D Mark III.

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 camera's 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 camera's firmware is already Version 1.2.3, it is not necessary to update the firmware.

The new Firmware Version 1.2.3 can be downloaded by clicking here.