Variable　resolution　fluctuation　electron　microscopy　(FEM)　experiments　are　implemented　with　hollow-cone　dark-field　transmission　electron　microscopy.　Medium　range　order　lengths　of　zirconium　and　iron　based　bulk　metallic　glasses　and　amorphous　silicon　nitride　are　determined　from　the　FEM　results.　It　shows　that　maximum　normalized　intensity　variances　of　FEM　images　occur　when　their　nominal　resolution　approaches　the　correlation　length　Lambda　of　the　amorphous　materials.　Additionally,　differences　in　the　length　and　magnitude　of　medium　range　order　are　compared　between　metallic　and　covalent　bond　amorphous　materials.　(c)　2012　Elsevier　Ltd.　All　rights　reserved.