The fully automatic and reliable calculation of the relative camera pose from 
image correspondences is one of the challenging tasks in photogrammetry and 
computer vision. The problem has not been solved satisfactorily, e.g. in case of 
critical camera motions or when observing special point configurations. 
Furthermore, some methods provide multiple solutions for the relative 
orientation. In this paper we compare various techniques, analyze their 
difficulties and give results on synthetic and real data. We show that in case 
of noisy data pose estimation of a single camera remains difficult. The use of 
multiple calibrated cameras that are fixed on a rig leads to additional 
constraints, which significantly stabilize the pose estimation process.