Electrostatic lenses are designed using an array of electrodes with cylindrical apertures precisely arranged on a line of symmetry. In this research, four cylindrical three-electrode electrostatic lenses were designed, three of them with unusual geometric shapes and one with a traditional geometric shape, as the same electrical voltages and the same geometric parameters were applied to all the proposed lenses in both acceleration and deceleration modes. The optical properties of each lens designed in acceleration and deceleration modes were calculated to show the extent to which linear magnification is affected by the geometry of electrostatic lenses, and the results were compared between the proposed lenses. As the results prove that the electrostatic lens geometry has an important effect in increasing or decreasing the linear magnification range, the best lens is selected from among the four designed lenses based on its optical performance. It was found that the lens with the concave inner surface of the electrode has the best optical performance of the rest of the lenses, which shows that the concavity of the inner surface of the electrode has a direct effect on the properties of electrostatic lenses. Which lens' has the largest linear magnification range (1.0-2.4) and (1.4-3.74), respectively, in both acceleration and deceleration modes. The calculations were made using the program (SIMION8.0).