Canon has posted a service advisory for its EOS 1D C and 1D X cameras. The company says that in some units, there is a possibility that focus hunting and inability to lock focus may may occur due to wear caused by insufficient lubrication within the camera’s driving mechanism. Furthermore, the viewfinder image may also become blurry or unsteady. Potentially affected products include Canon EOS 1D C units whose serial number's sixth digit is "1" and Canon EOS 1D X cameras whose serial number's sixth digit is either “1”, “2”, “3”, “4”, “5”, “6” or “7”. Potentially affected cameras will be inspected and repaired free of charge.