A charged particle multi-beamlet system for exposing a target using 10,000 or more electron beamlets, the system comprising: - means (1,2,3,4) for generating the 10,000 or more of the beamlets, including a radiation source for emitting an electron beam, a collimating system for collimating the electron beam, and a beam splitter for splitting the beam into the 10,000 or more beamlets; - a beamlet blanker array and beam stop array operating together for blocking or letting pass the beamlets; - an array of lens systems for focusing each beamlet onto the target, and - a deflection array included upstream of said lens systems, and adapted for scanning the beamlets; wherein the array of lens systems comprises exactly three projection lens plates (12,13,14) formed by a first projection lens plate, a second projection lens plate, and a third projection lens plate, each plate having a plurality of holes formed in it in an array and each plate coated in an electrically conductive coating to form an electrode on each plate, the first plate being furthest from the target and the third plate being closest to the target, wherein the deflection array is positioned at 0 to 5 millimeters from the first plate; wherein the three projection lens plates are adapted for forming an array of electrostatic projection lens systems at the location of the holes in the projection lens plates when control voltages are applied to the projection lens plates for generating a voltage difference between the electrodes, each projection lens system comprising projection lenses formed at corresponding holes of the projection lens plates so that each electron beamlet passes through a corresponding projection lens system; wherein the diameter of the lens system holes is in a range of 50 to 150 micrometers, and wherein a diameter of a coaxially aligned aperture of the beam stop array is in a range of 5 to 20 micrometers; wherein the holes in the projection lens plates have sufficiently uniform placement and dimensions to enable focusing all of the beamlets onto the surface of the target using the control voltages, the control voltages of each of the projection lens plates being common to all of the projection lens systems; wherein the system is adapted for applying a first common control voltage to the first plate, a second common control voltage to the second plate and a third common control voltage to the third plate; wherein the second common control voltage applied to the second plate is closer to the voltage of the radiation source than is the first common control voltage applied to the first plate, and the difference between the third common control voltage applied to the third plate and the voltage of the target is 0V; and wherein the focal length of the lens system is one millimeter or less. - means (1,2,3,4) for generating the 10,000 or more of the beamlets, including a radiation source for emitting an electron beam, a collimating system for collimating the electron beam, and a beam splitter for splitting the beam into the 10,000 or more beamlets; - a beamlet blanker array and beam stop array operating together for blocking or letting pass the beamlets; - an array of lens systems for focusing each beamlet onto the target, and - a deflection array included upstream of said lens systems, and adapted for scanning the beamlets;