Can one please comment on how FF WA lenses image circle expands as they are zoomed out? I am particularly interested on the Nikkor 17-35mm f2.8 (but other maker zoom of similar focal length will also be appreciated)... I would also appreciate it if one can can comment on how the Contax 645 vario-sonnar image circle expands as it is zoomed towards the longer end... thanks in advance to anyone that may contribute on the requirement.