diff --git a/clever/src/optical_flow.cpp b/clever/src/optical_flow.cpp
index 5975ad83..e051e072 100644
--- a/clever/src/optical_flow.cpp
+++ b/clever/src/optical_flow.cpp
@@ -219,16 +219,16 @@ private:
 	{
 		tf2::Quaternion prev_rot, curr_rot;
 		tf2::fromMsg(tf_buffer_.lookupTransform(frame_id, local_frame_id_, prev).transform.rotation, prev_rot);
-		tf2::fromMsg(tf_buffer_.lookupTransform(frame_id, local_frame_id_, curr).transform.rotation, curr_rot);
+		tf2::fromMsg(tf_buffer_.lookupTransform(frame_id, local_frame_id_, curr, ros::Duration(0.1)).transform.rotation, curr_rot);
 
 		geometry_msgs::Vector3Stamped flow;
 		flow.header.frame_id = frame_id;
 		flow.header.stamp = curr;
 		// https://en.wikipedia.org/wiki/Rotation_formalisms_in_three_dimensions#Quaternion_↔_angular_velocities
 		auto diff = ((curr_rot - prev_rot) * prev_rot.inverse()) * 2.0f;
-		flow.vector.x = diff.x();
-		flow.vector.y = diff.y();
-		flow.vector.z = diff.z();
+		flow.vector.x = -diff.x();
+		flow.vector.y = -diff.y();
+		flow.vector.z = -diff.z();
 
 		return flow;
 	}