[Greg McKaskle]

If the servo is jerky because it only moves a few times a second, you should try to speed up the loop. If your image size is large or if you have lots of processing, your framerate will drop and it will start jerking.

Another possibility, but less common, is that your target is too close to the camera. If the full image is filled with the target, it is by definition in the center, and you move the target some and the scene is still full, no movement. Only when the edge of the target enters the image will the servo move.

Greg McKaskle