Canon EOS 50D - Manual (Page 88)

88
Autofocus can fail to achieve focus (the focus confirmation light <o>
blinks) with certain subjects such as the following:
Subjects difficult to focus
Low-contrast subjects
(Example: Blue sky, solid-color walls, etc.)
Subjects in low light
Extremely backlit or reflective subjects
(Example: Car with a 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 one of the following:
(1) With One-Shot AF, focus an object at the same distance as the
subject and lock the focus before recomposing (p.50).
(2) Set the lens focus mode switch to <MF> and focus manually.
1
Set the lens focus mode switch to
<MF>.
2
Focus the subject.
Focus by turning the lens focusing
ring until the subject looks sharp in
the viewfinder.
When Autofocus Fails
Manual Focusing
If you press the shutter button halfway during manual focusing, the active
AF point and the focus confirmation light <o> in the viewfinder will light
when focus is achieved.
COP
Y