Binoculars Carl Zeiss Jena Stenor 5x12

Magnification: 5x
Aperture (objective diameter): 12 mm
Field of view: 8.3°
Visible field of view (eyepiece): 42°
Outlet pupil diameter: 2.4 mm
The closest focusing distance: 2.4 m
Width: 5.6 cm
Height (folded): 10 cm
Weight: 200 g
Production date: 1913.

   Stenor is one of the most original Carl Zeiss instruments. The binocular appeared in 1913 (although its unusual frame design was patented a year earlier, in 1912) and was produced without modifications until 1925/26.
   The unusual design of the device (folding frame with three hinges) allowed engineers to create one of the most compact prism binoculars of that time. And the use of Sprenger-Lehmann monolithic roof prisms reduced light loss and increased plasticity (volume effect).
   This "pocket" binocular was intended for those people for whom small size and minimum weight were important: for tourists, for people watching sports competitions, theatergoers, etc.
   The device has three hinges, the central hinge retainer is turned to the observer. This design solution is not very convenient, because the fixator rests on the forehead. The frame is marked with a scale of the inter-pupil distances.
   The scale of interpupillary distances is applied on the frame.
   The eyepiece bodies have a diagonal (at an angle of 45 degrees) knurling, the eyepiece base diameter is 13 mm. The height of the prism bodies is 24 mm, the width is 46.5 mm, and the thickness is 17 mm. The prism covers are attached to the body with three screws. The focusing of the device is separate. Lens diameter - 15 mm.
   The inscriptions on the left frame of the central joint are "Carl Zeiss". On the right frame - "Stenor 367262 5x". The inscription is printed in block letters against the background of a schematic image of a Carl Zeiss Tessar photographic lens.
   On the front, on the right center pivot frame is the inscription: “James Sinclair & Co Ltd 54 Haymarket London” (see photo). Obviously, the binoculars were sold in the network of stores of the well-known English company James Sinclair & Co Ltd, which was engaged in the production and sale of various optical equipment: cameras, binoculars, etc.
   The serial number of the binoculars is 367262, it was made in 1913 in a batch of 100 pieces.
   In 1924/25, the Stenor was replaced by the Stenotar 5x12 binoculars.