Solution
Check the focus mode switch on the lensClean the lens and camera electrical contacts
Mount the lens securely
Check the [Custom Controls] settings
Check the focus mode switch on the lens
Autofocus will not operate if the focus mode switch on the lens is set to [ MF ].
Set the focus mode switch on the lens to [ AF ], as shown in the image below.
Clean the lens and camera electrical contacts
The transfer of information between the camera and the lens is carried out by the electrical contacts on both the ( ) camera and the ( ) lens.
If the contacts on either the lens side or the camera side get dirty, communication cannot be carried out correctly, and in some cases the autofocus may not operate correctly.
If the lens or camera contacts get dirty, please clean them very gently with a clean, dry cloth.
Caution
Precautions on cleaning contacts:
Mount the lens securely
Both the camera and the lens mutually exchange information. For this reason, if the lens is not securely mounted, there may be cases where the autofocus does not operate correctly. Align the red dots on the lens and camera and turn the lens as shown by the arrow until it clicks in place.
Check the [Custom Controls] settings
If autofocus does not operate when the shutter button is pressed halfway, the [ : Custom Controls ] setting may be changed as follows.
In the above cases, please change the setting to [AF・Metering start]
For more information on changing the settings, please refer to Customizing the operation buttons (assigning functions other than the default functions to the buttons) (EOS 5DS / EOS 5DS R).
If you have checked all of the items listed above, but there is still no improvement, please contact the nearest Canon Service Center.
If you are experiencing trouble with a lens made by another manufacturer, you should contact manufacturer of that lens instead.