When Autofocus Fails; Manual Focusing - Canon EOS 50D Instruction Manual

When Autofocus Fails
Autofocus can fail to achieve focus (the focus confirmation light
<.
>
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.
Manual Focusing
Set the lens focus mode switch to
<MF>.
Focus the subject.
• Focus by turning the lens focusing
ring until the subject looks sharp in
the viewfinder.
[Q]
If you press the shutter button halfway during manual focusing, the active
AF point and the focus confirmation light
<e>
in the viewfinder will light
when focus is achieved.
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