A charged-particle multi-beamlet system comprising: a source of charged particles; a first multi-aperture plate having plural apertures disposed in a charged particle beam path of the system downstream of the source; a first multi-aperture selector plate having plural apertures; a carrier, wherein the first multi-aperture selector plate is mounted on the carrier; an actuator configured to move the carrier such that the first multi-aperture selector plate is disposed in the charged particle beam path of the system downstream of the source in a first mode of operation of the system, and such that the first multi-aperture selector plate is disposed outside of the charged particle beam path in a second mode of operation of the system; wherein the source, the first multi-aperture plate and the carrier are arranged such that a first number of charged particle beamlets is generated at a position downstream of both the first multi-aperture plate and the first multi-aperture selector plate in the first mode of operation, and that a second number of charged particle beamlets is generated at the position in the second mode of operation, wherein the first number of beamlets differs from the second number of beamlets; a focusing lens disposed in a beam path downstream of both the first multi-aperture plate and the first multi-aperture selector plate; a stage for mounting an object in an object plane disposed downstream of the focusing lens; characterized by a field-separating electrode having an aperture disposed in the charged particle beam path downstream of the focusing lens and upstream of the object plane; wherein the aperture of the field-separating electrode has a diameter (De) such that it is traversed by the first number of beamlets in the first mode of operation and by the second number of beamlets in the second mode of operation. a source of charged particles; a first multi-aperture plate having plural apertures disposed in a charged particle beam path of the system downstream of the source; a first multi-aperture selector plate having plural apertures; a carrier, wherein the first multi-aperture selector plate is mounted on the carrier; an actuator configured to move the carrier such that the first multi-aperture selector plate is disposed in the charged particle beam path of the system downstream of the source in a first mode of operation of the system, and such that the first multi-aperture selector plate is disposed outside of the charged particle beam path in a second mode of operation of the system; wherein the source, the first multi-aperture plate and the carrier are arranged such that a first number of charged particle beamlets is generated at a position downstream of both the first multi-aperture plate and the first multi-aperture selector plate in the first mode of operation, and that a second number of charged particle beamlets is generated at the position in the second mode of operation, wherein the first number of beamlets differs from the second number of beamlets; a focusing lens disposed in a beam path downstream of both the first multi-aperture plate and the first multi-aperture selector plate; a stage for mounting an object in an object plane disposed downstream of the focusing lens; characterized by a field-separating electrode having an aperture disposed in the charged particle beam path downstream of the focusing lens and upstream of the object plane; wherein the aperture of the field-separating electrode has a diameter (De) such that it is traversed by the first number of beamlets in the first mode of operation and by the second number of beamlets in the second mode of operation.