Canon EOS-1D X Mark III Firmware Update
(Photography Blog)

In response to a phenomenon that may occur when using the Canon EOS-1D X Mark III DSLR camera, Canon is introducing a future firmware update for the camera. The firmware update is scheduled to be available in early April. The phenomenon may occur when the camera is being used with the electronic level set to `Show` in the viewfinder display. In rare cases, the camera may not perform as it was designed to when operating the AF-ON button or shutter button. Canon is committed to listening to our customers and providing firmware updates accordingly. For more information on this future firmware update, please visit: Canon EOS-1D X Mark III Future Firmware Update