Canon EOS 90D Advanced User's Manual page 134

Selecting the AF Area and AF Point (Viewfi nder Shooting)
Shooting Conditions that Make Focusing Diffi cult
Subjects with very low contrast

(Example: Blue skies, solid-color fl at surfaces, etc.)
Subjects in very low light

Strongly backlit or refl ective subjects

(Example: Cars with highly refl ective bodies, etc.)
Near and distant subjects positioned close to an AF point

(Example: Animals in cages, etc.)
Light source such as dots of light positioned close to an AF point

(Example: Night scenes, etc.)
Subjects with repetitive patterns

(Example: Skyscraper windows, computer keyboards, etc.)
Subjects with fi ner patterns than an AF point

(Example: Faces or fl owers as small as or smaller than an AF point, etc.)
In such cases, focus in either of the following two ways.
(1) With One-Shot AF, focus on an object at the same distance as the
subject and lock the focus, then recompose the shot ( = 125).
(2) Set the lens's focus mode switch to <MF> and focus manually
( = 147).
Depending on the subject, focus may be achieved by slightly recomposing the
o
shot and performing AF operation again.
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