When Autofocus Fails; Subjects Difficult To Focus - Canon EOS 7D Mark II (G) Instruction Manual

When Autofocus Fails

Autofocus can fail to achieve focus (viewfinder's focus indicator <o>
blinks) with certain subjects such as the following:

Subjects Difficult to Focus

Subjects with very low contrast
(Example: Blue skies, solid-color flat surfaces, etc.)
Subjects in very low light
Strongly backlit or reflective subjects
(Example: Cars with highly reflective bodies, etc.)
Near and distant subjects framed close to an AF point
(Example: Animals in cages, etc.)
Subjects such as dots of light framed close to an AF point
(Example: Night scenes, etc.)
Repetitive patterns
(Example: Skyscraper windows, computer keyboards, etc.)
In such cases, focus by doing either of the following:
(1) With One-Shot AF, focus on an object at the same distance as the
subject and lock the focus, then recompose the shot (p.83).
(2) Set the lens's focus mode switch to <MF> and focus manually
(p.140).
Depending on the subject, focus may be achieved by slightly
recomposing the shot and performing AF operation again.
Conditions that make focusing difficult with AF during Live View shooting
or movie shooting are listed on page 306.
139