Canon EOS-1D C - Manual (Page 111)

111
When Autofocus Fails
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.
MF: Manual Focusing
Focusing ring
If you press the shutter button halfway while focusing manually, the focus
confirmation light <o> will light up when focus is achieved.
With 61-point automatic selection, when the center AF point achieves
focus, the focus confirmation light <o> will light up.
COP
Y