Af Sensitivity And Lens' Maximum Aperture - Canon EOS 1D Mark II N Instruction Manual

AF Sensitivity and Lens' Maximum Aperture

The EOS-1D Mark II N's AF points are all horizontal-line sensitive.
However, bright lenses with a large maximum aperture enable certain
AF points to work as cross-type sensors for higher AF precision.
(1) With lenses whose maximum aperture is f/2.8 or
larger, the AF points highlighted in the diagram will
work as cross-type sensors sensitive to both vertical
and horizontal lines. The remaining 38 AF points will
only be horizontal-line sensitive. The cross-type
sensor's vertical-line sensitivity is about three times
higher than its horizontal-line sensitivity.
(2) With the following L-series lenses whose
maximum aperture is f/4 or larger, the center AF
point will be a cross-type sensor with or without
an Extender attached. The remaining 44 AF
points will only be horizontal-line sensitive
(except with EF70-200mm f/2.8L USM +
Extender EF1.4x or EF1.4x ll).
· EF17-40mm f/4L USM
· EF28-80mm f/2.8-4L USM
· EF300mm f/4L USM
· EF300mm f/4L IS USM
· EF400mm f/4 DO IS USM
· EF500mm f/4L IS USM
· EF600mm f/4L USM
· EF600mm f/4L IS USM
· EF70-200mm f/4 L USM
With Extender EF1.4x or EF1.4x II:
· EF200mm f/2.8L USM
· EF200mm f/2.8L II USM
· EF300mm f/2.8L USM
· EF300mm f/2.8L IS USM
· EF400mm f/2.8L USM
· EF400mm f/2.8L II USM
· EF400mm f/2.8L IS USM
· EF70-200mm f/2.8L IS USM
With Extender EF2x or EF2x II:
· EF135mm f/2L USM
· EF200mm f/1.8L USM
87