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shooting speed of 4 frames-per-second despite the enormous file size generated by
16.7 megapixels.
The EOS-1Ds Mark II's sensor measures 36 by 24mm, a full 35mm frame, eliminating the
need for lens focal length conversion factors. Wide-angle lenses and the many unusual
or specialized lenses in the Canon EF family have their full, unfettered visual effect.
Autofocus System
The EOS-1Ds Mark II uses the exceptionally precise and fast autofocus system of the
EOS-1D Mark II with a few minor changes.
Viewfinder
up to a maximum aperture of f/5.6. The central AF point is a cross-type sensor that
supports vertical-line sensitivity to a maximum aperture of f/4 and horizontal-line
sensitivity to a maximum aperture of f/8.
There are three autofocus modes: One-Shot AF, which stops and locks when focus
is achieved, Predictive AI Servo AF, which constantly tracks subject movement and
focuses until the start of exposure, and Manual focusing, which has focus
confirmation with the in-focus indicator light and the superimposed AF point.
EOS Speedlites that have built-in AF-assist emit a near-infrared beam when
necessary to assist autofocus.
The AF-related circuitry and the AF algorithm in the 1Ds Mark II incorporate the new
1D Mark II design so that the AF performance clearly surpasses that of the 1Ds.
The EOS-1D and 1Ds had a single CPU for AF operations from focus detection to
lens-driving control. The EOS-1D Mark II and 1Ds Mark II have two CPUs responsible for
these functions.
Dividing tasks means decisions are made simultaneously rather than in sequence. In
Predictive AI Servo AF, statistical prediction using the focusing data from previous
focusing operations is incorporated. The number of focusing operations per unit time is
twice as many with the 1D and 1Ds. With shorter time intervals and more repetitive
focusing operations, the predictive AF control works effectively from the first shot even
with subjects moving erratically. Should the subject's movement change just before
shutter release, the shorter focusing operation interval means the predictive AF control
has a higher probability of catching it.
III. NEW AND IMPROVED DESIGN FEATURES
Like the EOS-1D Mark II, 1D, 1Ds and 1v, the
EOS-1Ds Mark II has a 45-point Area AF unit.
Manual selection of 45, 11 or 9 AF points is
possible. 38 of the 45 AF points are
vertical-line sensitive up to a maximum
aperture of f/5.6. 6 of the 7 AF points at the
center are cross-type sensors that are
vertical-line sensitive up to a maximum
aperture of f/2.8 and horizontal-line sensitive
9
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