Macro-Lenses are usually c-mount lenses. While "normal" C-Mount and CS-Mount lenses are used at distances of 50cm, 1m or even hundreds or thousands of meters, Macro-lenses are typically used at very short distances, this even could be a few millimeters .. they may of may not be used on larger distances. There's no fixed limit for the distances that distinguishes Macro lenses from "normal" lenses. Macro lenses however work better on short distances than on far distances! .. simply because they were designed for this purpose.