Telex Rangefinder (0435)
Info
Rangefinder that can be attached on top of a (old) camera to determine the distance to the subject. The parallax principle is used to, by means of the rotating knob, adjust the image in the highlighted rectangle when viewing through the eyepiece. The distance can then be read from the scale on the knob. The scale is from 0.55 to 10m and infinity.
References/Links/More Info
Mercury Camera - Article on rangefinders