Objectifs pour 1d mark 4

[bruno38]

C'est bizarre ce que tu dis. Normalement sur le 1D, il n'y a qu'à F8 que tu fonctionnes qu'avec le central. Je fais erreur ?

[GabiB]

C'est bizarre ce que tu dis. Normalement sur le 1D, il n'y a qu'à F8 que tu fonctionnes qu'avec le central. Je fais erreur ?

Les autres collimateurs sont fonctionnels, mais ils ne sont plus croisés, sauf le central qui est croisé jusqu'à f/4. En mode "simple", les autres collimateurs fonctionnent jusqu'à f/5.6, et le central jusqu'à f/8.

The 1D Mark II/N had 7, the 1D Mark III had 19, but the Canon EOS 1D Mark IV features 39 cross-type AF sensors that are functional during manual AF point selection (19 are cross-type functional with automatic AF point selection) with all f/2.8 and faster EF lenses as well as the following f/4 EF lenses:

17-40mm f/4 L USM
24-105mm f/4 L IS USM
70-200mm f/2.8 L IS USM + Extender EF 1.4x II
200mm f/2 L IS USM + Extender EF 2x II
300mm f/2.8 L IS USM + Extender EF 1.4x II
400mm f/2.8 L IS USM + Extender EF 1.4x II

Cross-type AF sensors are sensitive to both horizontal and vertical lines of contrast and are twice as sensitive to vertical lines as horizontal lines. Meaning, they will often be able to obtain focus when a horizontal-only sensor may not. The center AF point functions as a high-precision cross-type sensor with lenses that have a maximum aperture of f/4 or wider. All focus points are horizontal-line-sensitive-only with variable aperture EF lenses (such as an f/3.5-5.6 lens).

All 45 AF points (including the center AF point) remain horizontal-line-detection-functional with an f/5.6 lens. Currently, only Canon 1-Series bodies can autofocus with an f/8 max aperture lens (typically a lens + extender combination). Only the center AF point is functional at f/8.