|Thank you for using Canon products.
We have confirmed that the following phenomenon may occur during use of the EOS-1D X Mark III digital SLR camera. A new firmware release is planned for early April; once the new firmware is ready, we will make an announcement on our website.
When the camera is used with the electronic level set to “Show” in the viewfinder display, in rare cases, the camera may not perform normally when operating the AF-ON button or shutter button.
EOS-1D X Mark III (Firmware version 1.0.0)
Use the “Hide” setting for the electronic level in the viewfinder display.
Menu / Set-up 2 tab / Viewfinder display / Electronic level* [Hide]
* Default setting: [Hide]
We would like to offer our sincere apologies to users of these products who may have been inconvenienced by this issue.
In early-April 2020, Canon U.S.A. plans to release a firmware update to address the phenomenon listed above.
Should you have any questions about the announcement, please contact the Authorized Service Facility in your area or you may contact the Call Center within your region.