diff --git a/gtsam/geometry/CalibratedCamera.h b/gtsam/geometry/CalibratedCamera.h
index 12cfc706d..95ff66e68 100644
--- a/gtsam/geometry/CalibratedCamera.h
+++ b/gtsam/geometry/CalibratedCamera.h
@@ -49,14 +49,14 @@ namespace gtsam {
 		CalibratedCamera() {}
 
 		/// construct with pose
-		CalibratedCamera(const Pose3& pose);
+		explicit CalibratedCamera(const Pose3& pose);
 
     /// @}
     /// @name Advanced Constructors
     /// @{
 
 		/// construct from vector
-		CalibratedCamera(const Vector &v);
+		explicit CalibratedCamera(const Vector &v);
 
 		/// @}
 		/// @name Testable
diff --git a/gtsam/geometry/PinholeCamera.h b/gtsam/geometry/PinholeCamera.h
index d00f0fd90..8aee12064 100644
--- a/gtsam/geometry/PinholeCamera.h
+++ b/gtsam/geometry/PinholeCamera.h
@@ -51,7 +51,7 @@ namespace gtsam {
     PinholeCamera() {}
 
     /** constructor with pose */
-    PinholeCamera(const Pose3& pose):pose_(pose){}
+    explicit PinholeCamera(const Pose3& pose):pose_(pose){}
 
     /** constructor with pose and calibration */
     PinholeCamera(const Pose3& pose, const Calibration& k):pose_(pose),k_(k) {}
@@ -63,7 +63,7 @@ namespace gtsam {
     /// @name Advanced Constructors
     /// @{
 
-    PinholeCamera(const Vector &v){
+    explicit PinholeCamera(const Vector &v){
       pose_ = Pose3::Expmap(v.head(Pose3::Dim()));
       if ( v.size() > Pose3::Dim()) {
         k_ = Calibration(v.tail(Calibration::Dim()));
diff --git a/gtsam/nonlinear/Values-inl.h b/gtsam/nonlinear/Values-inl.h
index 7410ddade..c79d82a18 100644
--- a/gtsam/nonlinear/Values-inl.h
+++ b/gtsam/nonlinear/Values-inl.h
@@ -40,23 +40,30 @@ namespace gtsam {
     ValueCloneAllocator() {}
   };
 
+#if 0
   /* ************************************************************************* */
   class ValueAutomaticCasting {
     const Symbol& key_;
     const Value& value_;
+
   public:
     ValueAutomaticCasting(const Symbol& key, const Value& value) : key_(key), value_(value) {}
 
     template<class ValueType>
-    operator const ValueType& () const {
+    class ConvertibleToValue : public ValueType {
+    };
+
+    template<class ValueType>
+    operator const ConvertibleToValue<ValueType>& () const {
       // Check the type and throw exception if incorrect
       if(typeid(ValueType) != typeid(value_))
         throw ValuesIncorrectType(key_, typeid(ValueType), typeid(value_));
 
       // We have already checked the type, so do a "blind" static_cast, not dynamic_cast
-      return static_cast<const ValueType&>(value_);
+      return static_cast<const ConvertibleToValue<ValueType>&>(value_);
     }
   };
+#endif
 
   /* ************************************************************************* */
   template<typename ValueType>
@@ -76,6 +83,7 @@ namespace gtsam {
     return static_cast<const ValueType&>(*item->second);
   }
 
+#if 0
   /* ************************************************************************* */
   inline ValueAutomaticCasting Values::at(const Symbol& j) const {
     // Find the item
@@ -87,6 +95,7 @@ namespace gtsam {
 
     return ValueAutomaticCasting(item->first, *item->second);
   }
+#endif
 
   /* ************************************************************************* */
   template<typename TypedKey>
@@ -98,10 +107,12 @@ namespace gtsam {
     return at<typename TypedKey::Value>(symbol);
   }
 
+#if 0
   /* ************************************************************************* */
   inline ValueAutomaticCasting Values::operator[](const Symbol& j) const {
     return at(j);
   }
+#endif
 
   /* ************************************************************************* */
   template<typename ValueType>
diff --git a/gtsam/nonlinear/Values.h b/gtsam/nonlinear/Values.h
index e2a69d622..61e11ca4e 100644
--- a/gtsam/nonlinear/Values.h
+++ b/gtsam/nonlinear/Values.h
@@ -139,6 +139,7 @@ namespace gtsam {
     template<typename ValueType>
     const ValueType& at(const Symbol& j) const;
 
+#if 0
     /** Retrieve a variable by key \c j.  This non-templated version returns a
      * special ValueAutomaticCasting object that may be assigned to the proper
      * value.
@@ -147,6 +148,7 @@ namespace gtsam {
      * of the proper type.
      */
     ValueAutomaticCasting at(const Symbol& j) const;
+#endif
 
     /** Retrieve a variable using a special key (typically TypedSymbol), which
      * contains the type of the value associated with the key, and which must
@@ -163,8 +165,10 @@ namespace gtsam {
     const typename TypedKey::Value& operator[](const TypedKey& j) const {
       return at(j); }
 
+#if 0
     /** operator[] syntax for at(const Symbol& j) */
     ValueAutomaticCasting operator[](const Symbol& j) const;
+#endif
 
     /** Check if a value exists with key \c j.  See exists<>(const Symbol& j)
      * and exists(const TypedKey& j) for versions that return the value if it
diff --git a/gtsam/slam/BoundingConstraint.h b/gtsam/slam/BoundingConstraint.h
index 42f42e429..13ae33cfc 100644
--- a/gtsam/slam/BoundingConstraint.h
+++ b/gtsam/slam/BoundingConstraint.h
@@ -59,7 +59,7 @@ struct BoundingConstraint1: public NonlinearFactor1<VALUE> {
 	/** active when constraint *NOT* met */
 	bool active(const Values& c) const {
 		// note: still active at equality to avoid zigzagging
-		double x = value(c[this->key()]);
+		double x = value(c.at<X>(this->key()));
 		return (isGreaterThan_) ? x <= threshold_ : x >= threshold_;
 	}
 
@@ -127,7 +127,7 @@ struct BoundingConstraint2: public NonlinearFactor2<VALUE1, VALUE2> {
 	/** active when constraint *NOT* met */
 	bool active(const Values& c) const {
 		// note: still active at equality to avoid zigzagging
-		double x = value(c[this->key1()], c[this->key2()]);
+		double x = value(c.at<X1>(this->key1()), c.at<X2>(this->key2()));
 		return (isGreaterThan_) ? x <= threshold_ : x >= threshold_;
 	}
 
diff --git a/gtsam/slam/tests/testPose3SLAM.cpp b/gtsam/slam/tests/testPose3SLAM.cpp
index 4fa815cdc..9eb6b3c3c 100644
--- a/gtsam/slam/tests/testPose3SLAM.cpp
+++ b/gtsam/slam/tests/testPose3SLAM.cpp
@@ -50,8 +50,7 @@ TEST(Pose3Graph, optimizeCircle) {
 	// Create a hexagon of poses
 	double radius = 10;
 	Values hexagon = pose3SLAM::circle(6,radius);
-//  Pose3 gT0 = hexagon[PoseKey(0)], gT1 = hexagon[PoseKey(1)]; // FAIL: cannot cast ValueAutomaticCasting
-  Pose3 gT0 = hexagon.at<Pose3>(PoseKey(0)), gT1 = hexagon.at<Pose3>(PoseKey(1)); // Works
+  Pose3 gT0 = hexagon.at<Pose3>(PoseKey(0)), gT1 = hexagon.at<Pose3>(PoseKey(1));
 
 	// create a Pose graph with one equality constraint and one measurement
   shared_ptr<Pose3Graph> fg(new Pose3Graph);
diff --git a/tests/testExtendedKalmanFilter.cpp b/tests/testExtendedKalmanFilter.cpp
index 532305f24..0b4b222be 100644
--- a/tests/testExtendedKalmanFilter.cpp
+++ b/tests/testExtendedKalmanFilter.cpp
@@ -181,7 +181,7 @@ public:
 
   /** Vector of errors, whitened ! */
   Vector whitenedError(const Values& c) const {
-    return QInvSqrt(c[key1()])*unwhitenedError(c);
+    return QInvSqrt(c.at<T>(key1()))*unwhitenedError(c);
   }
 
   /**
@@ -190,8 +190,8 @@ public:
    * Hence b = z - h(x1,x2) = - error_vector(x)
    */
   boost::shared_ptr<GaussianFactor> linearize(const Values& c, const Ordering& ordering) const {
-    const X1& x1 = c[key1()];
-    const X2& x2 = c[key2()];
+    const X1& x1 = c.at<X1>(key1());
+    const X2& x2 = c.at<X2>(key2());
     Matrix A1, A2;
     Vector b = -evaluateError(x1, x2, A1, A2);
     const Index var1 = ordering[key1()], var2 = ordering[key2()];
@@ -318,7 +318,7 @@ public:
 
   /** Vector of errors, whitened ! */
   Vector whitenedError(const Values& c) const {
-    return RInvSqrt(c[key()])*unwhitenedError(c);
+    return RInvSqrt(c.at<T>(key()))*unwhitenedError(c);
   }
 
   /**
@@ -327,7 +327,7 @@ public:
    * Hence b = z - h(x1) = - error_vector(x)
    */
   boost::shared_ptr<GaussianFactor> linearize(const Values& c, const Ordering& ordering) const {
-    const X& x1 = c[key()];
+    const X& x1 = c.at<X>(key());
     Matrix A1;
     Vector b = -evaluateError(x1, A1);
     const Index var1 = ordering[key()];