[phenixbb] on real_space_refine

Dear All, After fitting a PDB into a 3.5-5 A resolution EM map by phenix.real_space_refine, should I still need to do a reciprocal space refine? For crystallography, the reciprocal space is in fact not purely imaginary, it corresponds to the diffaction spot. But for the EM data refinement, what is the reciprocal space refine? And what reciporce spce refine works on for the data refinement? Smith