Abstract: An apparatus for making distance measurements with a high degree of accuracy and a means for interpreting and displaying the results on a digital readout. A binary encoded scale which exhibits a one to one correspondence with discrete locations on said scale and the coded information at those locations is used in making the measurements. The scale is made using photographic reducing techniques. An optical detection system, comprising a magnifying lens, a plurality of light conducting fibers and phototransistors is used to read digital information from the binary encoded scale. An electronic circuit accepts digital code from the optical detection system, decodes it and displays the resulting information on a digital readout.