Canon EOS 5D Mark III Instruction Manual page 100

3 Customizing AF FunctionsN
: 15 points
Fifteen major AF points will be manually selectable.
: 9 points
Nine major AF points will be manually selectable.
With a lens from groups F to H (p.83-85), the number of manually selectable
AF points will be fewer.
Even with settings other than [61 points], AF point expansion (Manual
selection
and Zone AF (manual selection of Zone) are still possible.
When you press the <S> button, the AF points that are not manually
selectable will not be displayed.
Select AF area selection mode
You can limit the selectable AF area selection modes to suit your
shooting preferences. Turn the <5> dial to select a selection mode,
then press <0> to append a <X> checkmark. Then select [OK] to
register the setting.
: Expand AF area:
The camera will focus with the manually-selected AF point and the
adjacent AF points (above, below, left and right).
: Expand AF area:Surround
The camera will focus with the manually-selected AF point and the
surrounding AF points.
100
), AF point expansion (Manual selection, surrounding points),
For pinpoint focusing with a narrower AF
point than single-point AF.
One of the AF points set by [Selectable
AF point] setting can be selected.
: Manual select.:Spot AF
: Manual selection:1 pt AF