Voigtlander Kontur 6x6
Finder for Perkeo and Perkeo II 6X6 cameras (335/70 from 1952).
Strange accessory which can be fitted on any camera with an accessory shoe.
This device involves the use of both eyes instead of one,
one eye being applied to the finder and the other looking direct at the subject.
The eye applied to the finder sees simply a sharp, bright rectangle on an opaque black background,
the disengaged eye sees the view and the net result is a bright rectangle superimposed on the view.