Canon 2011B002, EOS-1 DS With f/2.8 and faster lenses, Lens’ Maximum Aperture and AF Sensitivity, With lenses whose maximum aperture is f/4 or larger

SSelecting the AF Point

Lens’ Maximum Aperture and AF Sensitivity

The EOS-1Ds Mark III can execute high-precision AF with lenses whose maximum aperture is f/2.8 or larger.

With f/2.8 and faster lenses*

Assist AF points Cross-type points

With the 19 AF points indicated by , high-precision, cross-type AF (both horizontal- and vertical-line sensitive) is possible. With cross-type AF, vertical-line detection is about 2 times as sensitive as horizontal-line detection. The remaining 26 Assist AF points are horizontal-line sensitive only.

* Excluding the EF24mm f/2.8 and EF28mm f/2.8.

With lenses whose maximum aperture is f/4 or larger

If the maximum aperture of the lens or Extender and lens combination is faster than f/4, the center AF point will work as a high-precision, cross-type point sensitive to both horizontal and vertical lines. The remaining 18 AF points and the 26 Assist AF points work as horizontal- line sensitive AF points.

With lenses whose maximum aperture is f/5.6 or larger

With lenses whose maximum aperture is larger than f/5.6, all the AF points, including the Assist AF points, will be horizontal-line sensitive only.

With lenses whose maximum aperture is f/8 or larger

With lenses whose maximum aperture is larger than f/8, AF will be possible with the center AF point which will be horizontal-line sensitive. AF will not work with the other AF points.

When the EF70-200mm f/2.8L USM is used with an Extender, use the center AF point only. The other AF points may cause a focusing error.

When using the EF24mm f/2.8 or EF28mm f/2.8 lens, the 13 AF points shown on the right can be used as cross-type points. The remaining 6 AF points will be horizontal-line sensitive.

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