We have confirmed that the following phenomenon may occur during the 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.
We sincerely apologize to users who may have experienced inconvenience due to this issue.
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.
Setting procedure: Menu / Set-up 2 tab / Viewfinder display / Electronic level* [Hide]
*Default setting: [Hide]
In early-April 2020, we plan to release a firmware update to address the phenomenon listed above.