diff --git a/openflexure_microscope/api/default_extensions/scan.py b/openflexure_microscope/api/default_extensions/scan.py
index 45579d3e..d741893a 100644
--- a/openflexure_microscope/api/default_extensions/scan.py
+++ b/openflexure_microscope/api/default_extensions/scan.py
@@ -203,7 +203,7 @@ class ScanExtension(BaseExtension):
                 if autofocus_enabled:
                     if fast_autofocus:
                         # Run fast autofocus. Client should provide dz ~ 2000
-                        autofocus_extension.fast_up_down_up_autofocus(
+                        autofocus_extension.fast_autofocus(
                             microscope, dz=autofocus_dz
                         )
                     else: