The lens focus mode switch is set to <MF> If the lens focus mode switch is set to <MF>, the AF mode can be selected, but the autofocus will not operate. Set the lens focus mode switch to <AF>. An extender (sold separately) is used If a separately-sold extender is used together with a lens whose maximum lens aperture value is f / 5.6 or higher, the autofocus will not operate.
You image can become blurred if the shutter speed is to slow. For example, if your camera says that the proper exposure would be f / 5.6 @ 1/30 of a second, then you would be able to increase your shutter speed to 1/125 of a second @ f /2.8. The rule of thumb to follow is: take the reciprocal of the focal length being used.
contrast detection Phase-difference detection EOS 5D Mark II No TTL secondary image-registration, phase detection 9 plus 6 Assist AF points contrast detection Phase-difference detection EOS 5D No TTL-CT-SIR with a CMOS sensor (TTL secondary image-registration, phase detection) 9 plus 6 Assist AF points - - EOS 6D No TTL secondary image-registration, phase detection 11 AF points (Center: Cross-type AF at f / 5.6
