A method, includes, with an illumination system, directing a first charged particle beam along a particle-optical axis to a specimen position, with an imaging system, receiving a second charged particle beam from the specimen position and directing the second charged particle beam to a detector, recording a first output of the detector, varying an excitation of an optical element of the imaging system with a controller so as to rotate the second charged particle beam at the detector through a yaw angle about the particle-optical axis, and recording a second output of the detector at the yaw angle.