Canon EOS 70DN Basic Instruction Manual page 272

AF Area Selection Modes
AF Operation and Maximum Lens Apertures
Maximum Lens Aperture: f/3.2 - f/5.6
With all AF points, cross-type AF sensitive to both vertical and
horizontal lines is possible. However, with the lenses below, the
peripheral AF points will detect only vertical or horizontal lines (no
cross-type focusing).
Lenses that Do Not Support Cross-Type Focusing with
Peripheral AF Points
Cross-type focusing at the <
following lenses:
EF35-80mm f/4-5.6, EF35-80mm f/4-5.6 II, EF35-80mm f/4-5.6 III,
EF35-80mm f/4-5.6 USM, EF35-105mm f/4.5-5.6, EF35-105mm f/4.5-5.6
USM, EF80-200mm f/4.5-5.6 II, EF80-200mm f/4.5-5.6 USM
Maximum Lens Aperture: f/1.0 - f/2.8
Besides cross-type focusing (vertical and horizontal lines detected
simultaneously), the center AF point can also perform high-precision,
vertical-line sensitive AF.*
The remaining 18 AF points perform cross-type focusing, as with when
maximum lens aperture is f/3.2 - f/5.6.
* Except with the EF28-80mm f/2.8-4L USM and EF50mm f/2.5 Compact Macro.
108
Cross-type focusing
Vertical line-sensitive focusing
Horizontal line-sensitive focusing
> and < > AF points is not possible wi h the