diff --git a/src/geomtools/sfx/crystfelio.py b/src/geomtools/sfx/crystfelio.py
index d906373ea6bbc7bbc41db4672f845226d1846fd9..0ed80aa9c642f74782a975a05a81ae6f1ee6c0b1 100644
--- a/src/geomtools/sfx/crystfelio.py
+++ b/src/geomtools/sfx/crystfelio.py
@@ -159,7 +159,7 @@ def parse_crystfel_streamfile(stream_filename, panels, connected_groups,
                 ])
                 hkl = np.array([re.h.values, re.k.values, re.l.values])
                 u, v, w = M.T @ hkl
-                s = clen / (1e-9 / lmd + w) / 200e-6
+                s = clen / (1e-9 / lmd + w) * res_avg
                 re['xa'] = u * s
                 re['ya'] = v * s