Canon EOS 10D - Manual (Page 71)

71
Focusing
4
When Autofocus Fails (Manual Focusing)
Autofocus can fail to achieve focus (the focus confirmation light blinks) with certain subjects
such as the following:
(a) Low-contrast subjects (blue sky, solid-color walls, etc.).
(b) Subjects in low light.
(c) Extremely backlit reflective subjects (car with a reflective body, etc.).
(d) Overlapping near and far objects (animal in a cage, etc.).
In such cases, do one of the following:
1. Focus an object at the same distance as the subject and lock the focus before recomposing.
2. Set the lens focus mode switch to < MF > (or < M > on older lenses) and focus manually.
(
→p.27)
Manual Focusing
Set the lens focus mode switch to < MF >
(or < M > on older lenses). 1
Focus by turning the lens focusing ring
until the subject is in focus in the
viewfinder. 2
•
If you press the shutter button halfway during manual focusing, the active AF point and
the focus confirmation light <
●> in the viewfinder will light when focus is achieved.
•
If focus cannot be achieved with an external Speedlite’s AF-assist beam, select the
center AF point. An off-center AF point may not be able to achieve focus.
•
With USM (Ultrasonic Motor) lenses (except those not having a distance scale), you
can use the focusing ring to fine focus after focus is achieved in the One-Shot AF
mode (full-time manual focusing).