Canon EOS-1D C EOS 1D X Instruction Manual - Page 110

When Autofocus Fails Autofocus can fail to achieve focus (the viewfinder's focus confirmation light blinks) with certain subjects such as the following: Subjects difficult to focus Very low-contrast subjects (Example: Blue sky, solid-color walls, etc.) Subjects in very low light Extremely backlit or reflective subjects (Example: Car with a highly reflective body, etc.) Near and far subjects covered by an AF point (Example: Animal in a cage, etc.) Repetitive patterns (Example: Skyscraper windows, computer keyboards, etc.) In such cases, do either of the following: (1) With One-Shot AF, focus on an object at the same distance as the subject and lock the focus before recomposing (p.67). (2) Set the lens focus mode switch to and focus manually (p.111). For conditions where AF can fail to achieve focus with [Live mode]/[u Live mode] during Live View shooting, see page 217. 110