That only works for static scenes with a predictable light source. So it wouldn't work with a light source that you don't control. Also it might or might not wo

That only works for static scenes with a predictable light source. So it wouldn't work with a light source that you don't control. Also it might or might not work for e.g. medical imaging because a person can't sit perfectly still. So for those cases you do need the million camera version.