Hi,
To take at least two photos of the object with different focus is in some way simular to what I do when doing macro photography and focus stacking.
http://www.astrofriend.eu/photograph...-stacking.html
It should work also with a lens that have a curvature to the field. Never tried that, and it is a waste of time to have to take several photos when not using all the pixels. More like, interesting things to examine.
/Lars