diff --git a/gtsam_unstable/slam/InvDepthFactor3.h b/gtsam_unstable/slam/InvDepthFactor3.h
index 3fd86f271..44d3b8fd0 100644
--- a/gtsam_unstable/slam/InvDepthFactor3.h
+++ b/gtsam_unstable/slam/InvDepthFactor3.h
@@ -92,7 +92,7 @@ public:
     } catch( CheiralityException& e) {
       if (H1) *H1 = Matrix::Zero(2,6);
       if (H2) *H2 = Matrix::Zero(2,5);
-      if (H3) *H2 = Matrix::Zero(2,1);
+      if (H3) *H3 = Matrix::Zero(2,1);
       std::cout << e.what() << ": Landmark "<< DefaultKeyFormatter(this->key2()) <<
           " moved behind camera " << DefaultKeyFormatter(this->key1()) << std::endl;
       return Vector::Ones(2) * 2.0 * K_->fx();