diff --git a/src/osg/AutoTransform.cpp b/src/osg/AutoTransform.cpp
index 440d2b1d5..1e870ce01 100644
--- a/src/osg/AutoTransform.cpp
+++ b/src/osg/AutoTransform.cpp
@@ -153,7 +153,7 @@ void AutoTransform::accept(NodeVisitor& nv)
 
                 if (getAutoScaleToScreen())
                 {
-                    float size = 1.0f/cs->pixelSize(getPosition(),1.0f);
+                    float size = 1.0f/cs->pixelSize(getPosition(),0.48f);
                     setScale(size);
                 }
 
diff --git a/src/osg/CullStack.cpp b/src/osg/CullStack.cpp
index 39be0ae2c..9b1724c2f 100644
--- a/src/osg/CullStack.cpp
+++ b/src/osg/CullStack.cpp
@@ -106,7 +106,7 @@ void CullStack::pushCullingSet()
                                   M(2,2)*P23,
                                   M(3,2)*P23 + M(3,3)*P33);
                                   
-        float scaleRatio  = 0.701f/sqrtf(scale_00.length2()+scale_10.length2());
+        float scaleRatio  = 0.7071067811f/sqrtf(scale_00.length2()+scale_10.length2());
 
         pixelSizeVector *= scaleRatio;