The LEP filter wheel provides fast, automated and efficient optical filter changing for microscopes. The filter wheel position is digitally encoded which makes it immune to slippage and skipping errors. Accurate filter positioning is essential to eliminate imaging errors that can affect the optical performance of the microscope and add unnecessary variations to measurement results. The LEP filter wheel is driven by a DC servo motor specifically selected for smooth, quiet, damped wheel motion. Flexibility and expandability is asssured with the MAC 5000/6000 controller system. The modular controller provides high performance and flexibility. Furthermore it is widely supported by almost any available imaging software application.