Hi,

What is the simplest way to have follow focus for video with 5D?
Is it really hard to keep in focus all time?

Cheers
Mitchell

Buy some rails and attach a Follow Focus unit that you bought from one of the many FF manufacturers.
Yes it takes a little practise to keep focus all the time. You will need a device like the Hoodman to view the subject with any clarity. Otherwise you have no hope. In short, you need to spend some bucks. Prices vary, mostly according to quality. Do a search on this board to find out opinions.

I got an "el cheapo" follow focus from India (CineCity), ordered some custom made carbon fiber rails from Utah and Redrock clamps -- works okay: My Camera... manhandled by Jessica on Vimeo

-- peer