Automatic Af Point Selection; Af Point Expansion; Af Micro-Adjustment - Canon EOS 1D Mark III - Digital Camera SLR User Manual

more precise. At the standard setting, the subject tracking sensitivity level is the same as
with the 1D Mark II
is impressive. (Subject-tracking sensitivity can be adjusted with C. Fn III –2, Slow to Fast,
-2 to +2.)
Even if AI Servo AF is used to focus on a still subject, stable control is enabled so that the
lens drive isn't constantly fine-tuning. If the subject starts to move, the focusing responds
immediately to detect the subject constantly.
Automatic AF Point The high detection-sensitive, cross-type AF points are now spread out over the Area AF.
Selection When One-Shot AF is combined with automatic focusing point selection, as with the
EOS 5D and 30D, the selection of the Area AF's bottom AF points is eliminated. From among
the remaining AF points, the AF point on the closest subject is set to be the main AF point.
This is a change from the Area AF of previous EOS-1D cameras where the main AF point
was set at where the most AF points lit up. The concept of eliminating the selection of the
least reliable AF points is the same as before. With the new algorithm, AF point selection
becomes more stable and consistent even if the area of the main AF point is smaller. When
AI Servo AF is combined with automatic focusing point selection, the EOS-1D Mark III's
behavior is the same as previous EOS-1D class cameras, where the subject is initially
acquired by center focusing point and subsequently tracked by all 45 points as necessary.

AF Point Expansion

AF expansion with a manually selected focusing selected point, C. Fn III –8, differs from
the EOS-1D Mark II
and focal distance, the AF point area does not change. With setting 1 (Enable left/right
assist points), the expanded area (on the left and right of the manually-selected AF point)
is enabled at all times. With setting 2 (Enable surrounding assist points), the expanded
area is enabled by one point all around the selected AF point.
With One-Shot AF, when focus is achieved with an
Assist AF point, the Assist AF point will light up via the
SI display. With AI Servo AF, the manually-selected AF
point and Assist AF point will not be displayed.

AF Micro-adjustment

AF precision is adjusted for the camera and lens to fall within
the lens' maximum aperture's depth of focus. However, there
are users who want to adjust it more minutely. They have
had to go to a Canon Service Center to have it done.
AF micro-adjustment is a feature developed for these users.
The user himself can now finely adjust the AF focusing
position. The adjustment range is ±20 steps in front of (-) or behind (+) the point of focus.
V. INCOMPARABLE EOS AUTOFOCUS, NOW EVEN BETTER
. Once an AF point starts tracking the subject, the tracking response
N
's settings. Depending on the AF mode (One-Shot AF or AI Servo AF)
N
C.Fn III -8-1
C.Fn III -8-2
: Selected AF point : Expansion points
C.Fn III-7
21