[Omaroo (Chris Malikoff)]

Thanks for that link Dennis. What a great device. I'm looking forward to creating some movie footage with the 5D-II, and focus was an issue - especially since you have to monitor it externally via the LCD as the shutter is open (viewfinder blocked in other words). On the 5D-II you can set your AF (whilst in live-view/movie mode) to "Live Mode" so that the camera makes the focus decision based on contrast variation - and this will then focus for you, BUT, it will not follow a subject and dynamically refocus. It's a bit of a compromise, but OK if you're shooting a relatively fixed subject - especially at a distance or with your aperture set appropriately.

I wonder if a split-screen focus mask would help too, rather than relying the standard Fresnel unit which is imprecise if all you've got is the LCD to work from.