Sharp focus is a difficult objective - the negatively charged electrons repel each other and provide an inherent defocusing action.
(the negatively charged electrons; provide; an inherent defocusing action) (the negatively charged electrons; repel; each other) Context(the negatively charged electrons repel,List([39, 77))):(Sharp focus; is; a difficult objective)
the negatively charged electrons repel,List([39, 77))
the negatively charged electrons the negatively charged electrons Sharp focus
provide repel is
an inherent defocusing action
each other
a difficult objective