Binoculars Carl Zeiss Jena Silvamar 6x military

Magnification: 6x
Aperture (objective diameter): 30 mm
Field of view: 8.5°
Exit pupil diameter: 5 mm
Visible field of view (eyepiece FOV): 50°
The closest focusing distance: 3.2 m
Width: 16.8 cm
Height: 11.6 cm
Weight: 645 g
Production date: 1913-1915.

   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)
   Silvamar is the first binocular model having 30 mm lenses. The device turned out to be very successful, characterized by high aperture, plasticity and wide field of view, and therefore it became the “champion” in terms of production time: Silvamar was produced from 1907 up to 1969 with various changes. It is a “civilian” model; similar military versions are marked as D.F.6x30 and Marineglas 6x(30).
This binocular specimen has the following interesting features that are not typical for most binoculars of this model of that time (the 204336 serial number corresponds to the 1910th year of production):
    - the lens caps are made with rounded edges and light-protective grooves for spurious flares minimization (3a type  - Hans T.Seeger. Zeiss-Feldstecher, Handfernglaser von 1894-1919, Modelle-Merkmale-Mythos, pp. 399-414). This design was applied from 1913 to 1915;
   - the eyepieces’ body has a transverse (horizontal/vertical) knurling (on Carl Zeiss Jena until 1913 and on Carl Zeiss Wien until 1918);
   - the eyepieces front lens’s diameter is equal to 11.5 mm (from 1913-14);
   - the central hinge latch (clamp) is of the large diameter, as in military models.
   The binoculars’ coffer is of very rare dark green color. It has a wide loop for belt fixation (an attribute of military application). In addition, it has features that are typical for Carl Zeiss Wien – the coffers of Carl Zeiss Viennese branch production: color filters and spare eyecup “pockets” and a metal rim (a very similar coffer for Carl Zeiss Wien Telex 6x21 military binocular is presented in Hans T.Seeger book, Zeiss Handfernlaser 1919-1946, Modelle-Merkmale-Mythos, p. 662). These binocular’s features indicate that it was most likely produced in Vien in 1913-1915 and that it is a complete analogue of Carl Zeiss Wien M 9/13 Z Feldstecher military binocular, however, the upper prism covers were replaced by Silvamar covers or the original ones were engraved differently for some unknown reasons.
   The binocular’s serial number is in the 12x monocular number range (204301-204400 Hans T. Seeger. Zeiss-Feldstecher, Handfernglaser von 1894-1919, Modelle-Merkmale-Mythos, p. 808).
   Compared to older version of this model (https://binocollection.com/catalog/binoculars-carl-zeiss-jena-silvamar-6x.html), this binocular’s field of view is slightly increased (from 8.4° to 8.5°), however, the eyepieces’ front lenses were decreased to 11.5 mm (this value was equal to 12.7 mm in old version).
   The base diameter of this device’s eyepieces is equal to 24.5 mm and the top prismatic cap width is equal to 52 mm (see photo). The eyepieces have a diopter scale and the transverse knurling. The binocular’s case height (including the upper prism cover) is equal to 78 mm; the binocular’s height without lens frame is equal to 67 mm (this value was equal to 55 mm in old version).
   There are inscriptions Carl Zeiss Jenna on the left prism cover. There is also an inscription Silvamar 204336 6x on the right prism cover. The inscription is made in block letters on the background of Carl Zeiss Tessar photo lens schematic image.
      An early binocular’s version can be checked here: https://binocollection.com/catalog/binoculars-carl-zeiss-jena-silvamar-6x.html
      The binocular’s model with central focusing, namely Silvarem 6x, was produced in 1909 https://binocollection.com/catalog/binoculars-carl-zeiss-jena-silvarem-6x.html