A closed-loop focusing system and method positions a focusing assembly to a desired positioned. A feedback positioning device, such as a linear encoder, provides an actual or "read" value for the linear movement of the focusing assembly. The desired position is compared to the actual position of the focusing assembly. If the two values are outside of a predetermined tolerance or valid range, then an audible or visual warning will be given. When a laser source is utilized with the focusing system, laser operation will be prevented if the two values are outside of an acceptable range. However, if the difference between the desired position and the actual position are within an acceptable range, the focusing assembly is repositioned to allow real-time systematic correction of the position of the focusing assembly.