1. A method for correcting an error in an estimated pose of a moveable camera, the camera being at least a part of a camera system that generates an output image on the basis of the camera pose, the method comprising: taking incremental pose measurements for the camera over time and estimating a pose of the camera using the incremental pose measurements, the estimated camera pose having an error; determining a pose correction on the basis of the difference between an absolute pose measurement for the camera and the estimated camera pose; monitoring a rate of change in the camera image caused by a change in the camera; and periodically adjusting a parameter of the camera system based on the incremental pose measurements, the adjustment further being set in order to effect the pose correction so as to correct for the estimated camera pose error, the pose correction being effected at a rate based on the monitored rate of change in the camera image.