A new method for observing full domains in thin magnetic films by electron microscopy is described. Observations are made with standard transmission instruments utilizing an off‐centered objective aperture diaphragm as a knife edge. The method has the high‐resolution advantage that the microscope is focused on the specimen during domain observations. Limitations of the method and comparisons with the previously reported defocusing technique are presented. Applications to the interpretation of complex domain patterns and cross‐tie walls are demonstrated. The observations were made with electrostatic‐focusing microscopes, the AEG‐Zeiss and Tru¨b‐Ta¨uber instruments, which allow the use of full objective power without influencing the magnetization distribution of low coercive force films. A second method using a knife edge is proposed that would potentially permit a simple measurement of the detailed magnetization distribution of a domain wall in a thin film.