Yesterday CANON issued a product advisory for the EOS 1D C:
In some units of the models listed below, there is a possibility that the following phenomena may occur due to wear caused by insufficient lubrication within the camera’s driving mechanism.
1. AF searches but does not lock in on the subject.
(Caused by minute particles produced by wear mentioned above.)
2. The image shown in the viewfinder is “blurry” or “not steady”.
(Occurs if wear progresses.)
Potentially Affected Products
1. EOS-1D X: If the sixth digit of the serial number is “1”, “2”, “3”, “4”, “5”, “6” or “7”, the phenomena described above may occur.
2. EOS-1D C: If the sixth digit of the serial number is “1”, the phenomena described above may occur.
NOTE: If the camera’s battery compartment contains one of the markings illustrated below, the camera is NOT affected by the
phenomena described above even if the sixth digit of the serial number is one of the numbers mentioned above.
Markings of UNAFFECTED cameras:
Please contact you local Canon dealer for more information.