So I was wondering about the 5DII's new video capabilities, specifically its AF system.
To those of you who've used the contrast detection AF in live view, how is the focus detection? I understand it's slower than traditional AF, but is it smooth? Is it jumpy? Can it track a moving target in servo mode?
What sort of AF limitations should we expect compared to the traditional AF system?
Well it can't be all bad if that's what they've been using on video cameras for years and years. It would not be quite as critical as for a higher-resolution still photo image.
The smoothness depends a lot on how the camera is programmed to respond and on how much of the scene is being focused.
Video cameras have generally had small sensors and large DOF, so using a larger format camera with small DOF may be a problem unless they restrict the maximum aperture that can be used. Usually, however, AF will be done at the shooting aperture which is often smaller than maximum.
