A method of inspecting a specimen with an array of primary charged particle beamlets in a charged particle beam device is described. The method includes generating a primary charged particle beam with a charged particle beam emitter; illuminating a multi-aperture lens plate with the primary charged particle beam to generate the array of primary charged particle beamlets; correcting a field curvature with at least two electrodes, wherein the at least two electrodes include aperture openings; directing the primary charged particle beamlets with a lens towards an objective lens; guiding the primary charged particle beamlets through a deflector array arranged within the lens; wherein the combined action of the lens and the deflector array directs the primary charged particle beamlets through a coma free point of the objective lens; and focusing the primary charged particle beamlets on separate locations on the specimen with the objective lens.