diff --git a/gtsam/geometry/triangulation.cpp b/gtsam/geometry/triangulation.cpp
index 9e1575801..474689525 100644
--- a/gtsam/geometry/triangulation.cpp
+++ b/gtsam/geometry/triangulation.cpp
@@ -30,7 +30,7 @@ namespace gtsam {
  * @param rank_tol SVD rank tolerance
  * @return Triangulated Point3
  */
-Point3 triangulateDLT(const std::vector<Matrix>& projection_matrices,
+Point3 triangulateDLT(const std::vector<Matrix34>& projection_matrices,
     const std::vector<Point2>& measurements, double rank_tol) {
 
   // number of cameras
@@ -41,7 +41,7 @@ Point3 triangulateDLT(const std::vector<Matrix>& projection_matrices,
 
   for (size_t i = 0; i < m; i++) {
     size_t row = i * 2;
-    const Matrix& projection = projection_matrices.at(i);
+    const Matrix34& projection = projection_matrices.at(i);
     const Point2& p = measurements.at(i);
 
     // build system of equations
diff --git a/gtsam/geometry/triangulation.h b/gtsam/geometry/triangulation.h
index 864a60664..798a7e9dc 100644
--- a/gtsam/geometry/triangulation.h
+++ b/gtsam/geometry/triangulation.h
@@ -53,7 +53,7 @@ public:
  * @return Triangulated Point3
  */
 GTSAM_EXPORT Point3 triangulateDLT(
-    const std::vector<Matrix>& projection_matrices, // TODO: Use the fact that projection matrices sizes are known at compile time
+    const std::vector<Matrix34>& projection_matrices,
     const std::vector<Point2>& measurements, double rank_tol);
 
 ///
@@ -189,12 +189,11 @@ Point3 triangulatePoint3(const std::vector<Pose3>& poses,
     throw(TriangulationUnderconstrainedException());
 
   // construct projection matrices from poses & calibration
-  std::vector<Matrix> projection_matrices;
+  std::vector<Matrix34> projection_matrices;
   BOOST_FOREACH(const Pose3& pose, poses) {
     projection_matrices.push_back(
-        sharedCal->K() * sub(pose.inverse().matrix(), 0, 3, 0, 4));
+        sharedCal->K() * (pose.inverse().matrix()).block<3,4>(0,0));
   }
-
   // Triangulate linearly
   Point3 point = triangulateDLT(projection_matrices, measurements, rank_tol);
 
@@ -240,12 +239,11 @@ Point3 triangulatePoint3(
 
   // construct projection matrices from poses & calibration
   typedef PinholeCamera<CALIBRATION> Camera;
-  std::vector<Matrix> projection_matrices;
-  BOOST_FOREACH(const Camera& camera, cameras)
-    projection_matrices.push_back(
-        camera.calibration().K()
-            * sub(camera.pose().inverse().matrix(), 0, 3, 0, 4));
-
+  std::vector<Matrix34> projection_matrices;
+  BOOST_FOREACH(const Camera& camera, cameras) {
+  Matrix P_ = (camera.pose().inverse().matrix());
+    projection_matrices.push_back(camera.calibration().K()* (P_.block<3,4>(0,0)) );
+   }
   Point3 point = triangulateDLT(projection_matrices, measurements, rank_tol);
 
   // The n refine using non-linear optimization