diff --git a/lib/Slic3r/GUI/PreviewCanvas.pm b/lib/Slic3r/GUI/PreviewCanvas.pm
index ffa7c61b7..e8f0b4c36 100644
--- a/lib/Slic3r/GUI/PreviewCanvas.pm
+++ b/lib/Slic3r/GUI/PreviewCanvas.pm
@@ -90,7 +90,7 @@ sub new {
         my $zoom = $e->GetWheelRotation() / $e->GetWheelDelta();
         $zoom = max(min($zoom, 4), -4);
         $zoom /= 10;
-        $self->_zoom($self->_zoom * (1-$zoom));
+        $self->_zoom($self->_zoom / (1-$zoom));
         
         # In order to zoom around the mouse point we need to translate
         # the camera target