We briefly describe the basics of electron holography, the hologram formation, as well as its acquisition and reconstruction. Our test sample requires a holographic field of view in the medium magnification range of about 20-30 kX. Two of the microscopes. (Philips) utilized for this Round Robin experiment feature a Lorentz lens for medium magnification whereas the third one (Hitachi) requires a special lens current setting in its free lens control mode. The phase images from electron holograms reveal potential differences caused by active dopants. The comparison between the phase images reconstructed from our test holograms taken with the different microscopes. show excellent agreement. (C) 2004 American Vacuum Society.