Ion implantation systems and scanning systems are provided, in which a focus adjustment component is provided to adjust a focal property of an ion beam to diminish zero field effects of the scanner upon the ion beam. The focal property may be adjusted in order to improve the consistency of the beam profile scanned across the workpiece, or to improve the consistency of the ion implantation across the workpiece. Methods are disclosed for providing a scanned ion beam to a workpiece, comprising scanning the ion beam to produce a scanned ion beam, adjusting a focal property of an ion beam in relation to zero field effects of the scanner upon the ion beam, and directing the ion beam toward the workpiece.