Barry Johnston
New member
There are other things to consider before purchasing a lens.
This info is pertinent to my MkII N, and expect it would be similar to other 1D's and other EOS cameras.
The EOS-1D MkII 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 (below), 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. Other L-series lenses whose maximum aperture is f/4 or larger, the centre 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 II)
(Malurus lamberti - Variegated Fairywren)
There is a list of lenses listed in the instruction manual.
I think this information is worth considering, depending on the type of photography the lens is intended for.
Any other comments or thoughts on this?
Cheers,
Barry.
This info is pertinent to my MkII N, and expect it would be similar to other 1D's and other EOS cameras.
The EOS-1D MkII 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 (below), 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. Other L-series lenses whose maximum aperture is f/4 or larger, the centre 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 II)
(Malurus lamberti - Variegated Fairywren)
There is a list of lenses listed in the instruction manual.
I think this information is worth considering, depending on the type of photography the lens is intended for.
Any other comments or thoughts on this?
Cheers,
Barry.