Canon EOS 80D - Manual (Page 136)

136
Autofocus may 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.)
 Subjects with repetitive patterns
(Example: Skyscraper windows, computer keyboards, etc.)
In such a case, 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.81).
(2) Set the lens’s focus mode switch to <MF> and focus manually
(p.137).
When Autofocus Fails
 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 284.