diff --git a/rtgui/perspective.cc b/rtgui/perspective.cc
index 060a62b04..c60037540 100644
--- a/rtgui/perspective.cc
+++ b/rtgui/perspective.cc
@@ -474,7 +474,7 @@ void PerspCorrection::setDefaults (const ProcParams* defParams, const ParamsEdit
         camera_crop_factor->setDefaultEditedState (pedited->perspective.camera_crop_factor ? Edited : UnEdited);
         camera_focal_length->setDefaultEditedState (pedited->perspective.camera_focal_length ? Edited : UnEdited);
         camera_pitch->setDefaultEditedState (pedited->perspective.camera_pitch ? Edited : UnEdited);
-        camera_scale->setDefaultEditedState (pedited->perspective.camera_scale? Edited : UnEdited);
+        camera_scale->setDefaultEditedState (std::abs(pedited->perspective.camera_scale-1) > 1e-6 ? Edited : UnEdited);
         camera_roll->setDefaultEditedState (pedited->perspective.camera_roll ? Edited : UnEdited);
         camera_shift_horiz->setDefaultEditedState (pedited->perspective.camera_shift_horiz ? Edited : UnEdited);
         camera_shift_vert->setDefaultEditedState (pedited->perspective.camera_shift_vert ? Edited : UnEdited);