Optical tracking such as StarTracker relies on an additional camera sensor, processing unit and reflective stickers to calculate the absolute position of the main camera. This method gives you much more freedom to operate the cameras anywhere in the studio but the graphics will have noise. On the other hand, mechanical tracking systems are based around the use of measuring sensors or encoders attached to a crane, camera heads or pedestals. These encoders will give angular and positional measurements that allow an operator to accurately track the position of the camera.