Canon 9443a002 Instruction Manual - Page 73

AF Sensitivity and Lens' Maximum Aperture The EOS-1Ds Mark II'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 brighter, 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 EF 70-200mm f/2.8L USM + Extender EF 1.4x). · EF 28-80mm f/2.8-4L USM · EF 300mm f/4L USM · EF 300mm f/4L IS USM · EF 400mm f/4 DO IS USM · EF 500mm f/4L IS USM · EF 600mm f/4L USM · EF 600mm f/4L IS USM · EF 70-200mm f/4 L USM ¡With Extender EF 1.4x or EF 1.4x II: · EF 200mm f/2.8L USM · EF 200mm f/2.8L II USM · EF 300mm f/2.8L USM · EF 300mm f/2.8L IS USM · EF 400mm f/2.8L USM · EF 400mm f/2.8L II USM · EF 400mm f/2.8L IS USM · EF 70-200mm f/2.8L IS USM ¡ With Extender EF 2x or EF 2x II: · EF 135mm f/2L USM · EF 200mm f/1.8L USM 73