A charged-particle tool including: a condenser lens array configured to separate a beam of charged particles into a first plurality of sub-beams along a respective beam path and to focus each of the sub-beams to a respective intermediate focus; an array of objective lenses, each objective lens configured to project one of the plurality of sub-beams onto a sample; a corrector including an array of elongate electrodes, the elongate electrodes extending substantially perpendicular to the beam paths of the first plurality of sub-beams and arranged such that a second plurality of the sub-beams propagate between a pair of the elongate electrodes, the second plurality of sub-beams being a subset of the first plurality of sub-beams; and an electric power supply configured to apply a potential difference between the pair of elongate electrodes so as to deflect the second plurality of sub-beams by a desired amount.