camera_calibration set_camera_info Service not found

edit

I want to calibrate a stereo camera with camera_calibration on Indigo in Ubuntu 14.04. I have two separate webcams connected and use gscam to return the video stream. However when I want to calibrate them using camera_calibration by typing:

rj@rj-K55VD:~/catkin_ws$ rosrun camera_calibration cameracalibrator.py --size 8x6 --square 0.108 --approximate=0.1 right:=/right/camera/image_raw left:=/left/camera/image_raw right_camera:=/right/camera left_camera:=/left/camera

I get the following output:

('Waiting for service', '/left/camera/set_camera_info', '...')
Service not found
('Waiting for service', '/right/camera/set_camera_info', '...')
Service not found

I guess it tries to look for camera_info which is published. Rostopic list gives the following output

rj@rj-K55VD:~/catkin_ws$ rostopic list
/left/camera/camera_info
/left/camera/image_raw
/right/camera/camera_info
/right/camera/image_raw /rosout
/rosout_agg

So I do not know what the problem is or what is missing since the cameras seems to be running fine.

Just to be complete, the xml code of one of the camera launch file is

<launch>
  <!-- This launchfile should bring up a node that broadcasts a ros image
       transport on /webcam/image_raw -->

  <arg name="DEVICEl" default="/dev/video2"/>
  <!-- The GStreamer framerate needs to be an integral fraction -->
  <arg name="FPS" default="30/1"/>
  <arg name="PUBLISH_FRAME" default="false"/>

  <node ns="left" name="gscam_driver_v4l" pkg="gscam" type="gscam" output="screen">
    <param name="camera_name" value="default"/>
    <param name="camera_info_url" value="package://gscam/examples/uncalibrated_parameters.ini"/>
    <param name="gscam_config" value="v4l2src device=$(arg DEVICEl) ! video/x-raw-rgb,framerate=$(arg FPS) ! ffmpegcolorspace"/>
    <param name="frame_id" value="/v4l_frame_l"/>
    <param name="sync_sink" value="true"/>
  </node>

  <node if="$(arg PUBLISH_FRAME)" name="v4l_transform" pkg="tf" type="static_transform_publisher" args="1 2 3 0 -3.141 0 /world /v4l_frame 10"/>
</launch>

I have an identical launch file for the right camera, only with some of the node names a bit different to avoid confusions.