diff --git a/gui/src/aaregui/panels/smart_rotation_panel.py b/gui/src/aaregui/panels/smart_rotation_panel.py
index 897cc418..08c0c90d 100644
--- a/gui/src/aaregui/panels/smart_rotation_panel.py
+++ b/gui/src/aaregui/panels/smart_rotation_panel.py
@@ -323,6 +323,8 @@ class SimpleRotationSettingsPanel(QWidget):
             self.transmission = 1.0
 
         self.dtz = self.__d.diffraction.calc_dtz_mm(d_tar)
+        if self.dtz < 108:
+            self.dtz = 108
 
         self.transmission_label.setText(f"{self.transmission * 100:.1f}")
         self.image_time_label.setText(f"{self.image_time_s:.4f}")