Combining microprocessor control and advanced optics, the LF210 laser autofocus from Prior Scientific Inc. is suitable for reflective specimens. The compact module incorporates optics that adjust to various microscopes and optical systems with infinity-corrected optics. The focus trim and loop gain are automatically adjusted in the processor, providing higher throughput. The digital control senses when the sample has moved out of the field of view and stops the focus drive, while LEDs present the focus status. When operated with the LF100K digipot/keypad, the system provides a microstepping drive for bipolar stepper motors, a programmable voltage output for direct current or piezo Z control, and voltage output for the open-loop height sensor operation. Gains, speed, servo loops and other parameters are programmable.