In order to target a 1080p output and make the most of the available headroom resolution of 4k footage the project needs to be set at 1080p during editing. By doing this it means I can effectively zoom in 200% without loosing quality due to the footage being 4 times larger than the editing resolution. This cant be confused with outputting 1080p, it must be done in the editing to get work with a lossless zoom.
So the question is where is such a setting? In Camtasia, not what I would regarded a professional video editing application does just this, set editing resolution to allow headroom zooming from 4k footage.
Thanks,
Dan