Telecentric scanning lenses are special configurations in which the arrangement of optics is designed to focus down the beam so that it is always perpendicular to the flat field. This is accomplished by ensuring that the system 'stop' is located at the front focal point of the lens system. The 'stop' is located at the position where the beam is deflected from the axis. In a single-axis scanning system, this location is at the scanning mirror. For two-axis scanning, the stop is mid-way between the mirrors. Adaptors for major scan head providers are available upon request.