Binoculars Carl Zeiss Jena 6x30

Magnification: 6x
Aperture (objective diameter): 30 mm
Field of view: 8.4°
Exit pupil diameter: 5 mm
Visible field of view (eyepiece FOV): 50°
The closest focusing distance: 4 m
Width: 16.8 cm
Height: 11.5 cm
Weight: 685 g
Production date: 1914.

   In 1907, Carl Zeiss radically changed the framework and the design of his binoculars, replacing "civilian" models Feldstecher 6 Fach by Telex, Feldstecher 8 Fach by Telact, Jagdglas by Silvamar and Feldstecher 12 Fach by Telefort. The new devices’ detailed characteristics were published in the 74-th volume of Carl Zeiss catalog in August 1907. The optical characteristics were significantly improved in new devices (the field of view and the objective diameter were increased, optical aberrations were decreased), and the devices’ design was also changed: the central hinge and the “lugs” for a neck strap were not attached to binocular with the help of screws any more, they became integral with it instead, an eccentric objective alignment system appeared and its frame design was also changed, the prism covers spanned the binoculars’ carcass, and they were lubricated with a special compound at the joint points in order to improve impermeability. Moreover, the prisms inside the binoculars were no longer pressed by prism covers – they were fixed with the help of special flat springs instead. It helped increasing the device’s reliability greatly. Actually, the binoculars have survived in such appearance up to present days (see Hans T.Seeger. Zeiss-Feldstecher, Handfernglaser von 1894-1919, Modelle-Merkmale-Mythos, pp.399-414)
   The device under consideration is outwardly identical to Carl Zeiss Marineglas military binocular (its civilian analogue is Silvamar). It has rounded objective covers, the upper and lower prism covers are made of brass and they are fixed to the carcass with the help of three screws. The prism covers’ width is equal to 52 mm (see photo). The binocular’s body height (including upper prism cover) is equal to 77 mm. The eyepieces’ base diameter is equal to 24.5 mm; the eyepieces’ front lens diameter is equal to 12 mm. In addition, the eyepieces have a diopter scale and a diagonal knurling.
   The binocular’s “military" application is proved by the large diameter of the central hinge clamp (lock), which is made of brass, as well as a spring-type  protective cover of the eyepieces (the so-called "raincoat"). The interpupillary distances scale is indicated on the upper hinge disk.
   There are inscriptions “Carl Zeiss Jena” on the left prism cover. There is also an inscription “6x30 410954” on the right prism cover. The inscription is made in block letters with the help of white paint against the background of Carl Zeiss Tessar photo lens schematic image.
   So what binocular’s model is this? Based on the above mentioned design peculiarities, it can be assumed that the binocular was produced not earlier than 1913/14. In addition, its serial number "410954" falls into a 1000 pieces batch of Marineglas 6x military binoculars made exactly in 1914. Taking these facts into consideration, we can assume that it is a military binocular Carl Zeiss Marineglas 6x produced in 1914, which was later repaired and which changed the name of the model for unknown reasons. Perhaps the reason for its name change is in the terms of Versailles Peace Treaty, which was concluded by Germany at the end of the World War I. According to it, Germany had no right to possess/produce military optical devices, so they decided that the binocular had to become the "civilian" one after some repairs...
   The analogical Marineglas 6x model can be checked by the following link: https://binocollection.com/catalog/binoculars-carl-zeiss-jena-marineglas-6x-2.html
  The binocular’s "civilian" analogues – the Silvamar 6x models can be checked here: https://binocollection.com/catalog/germania/zeiss/grazhdanskie-binokli/silvamar-6x