Binoculars Carl Zeiss Jena Telact 8x (2)

Magnification: 8x
Aperture (objective diameter): 24 mm
Field of view: 6.6°
Exit pupil diameter: 3 mm
Visible field of view (eyepiece FOV): 52.8°
The closest focusing distance: 6 m
Width: 14.8 cm
Height: 12.5 cm
Weight: 540 g
Production date: 1911.

   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)
   Telact is a new design fine model with perfect optical features, 8x magnification and a 24mm lens. It’s a civilian model; similar military models are marked as D.F.8x, D.F.8x24 and D.F.95 n/A.
   The binocular “civilian” use is proved by the central hinge clamp’s (fastener’s) small diameter (see photo), which has a hole for a knob (included to binoculars delivery kit), with the help of which the hinge could have been finally fixed depending on the observer’s interpupillary distance. There is an interpupillary distance scale on the upper hinge disc. Telact was produced in 3 versions with various design changes until 1915 :
   1st version: in which the cap of frame lens and the lower prismatic cover were made as a single part (since 1907) and the eyepiece case had the “transverse” knurling (see photo)
   2nd version: with the two-ring type lens frames (starting from 1908 and up to the end of 1914);
   3th version: with the rounded lens covers (from 1913 to 1915)
   This device belongs to second version (with the two-ring type lens frames) and it has the eyepieces with base diameter equal to 24.5 mm and the top prism cover width equal to 50 mm (see photo). The eyepieces possess the diopter scale and the transverse knurling. The binoculars case height (including upper prismatic cover) is equal to is 66 mm.
There are inscriptions “Carl Zeiss Jena” on the left prism cover. There is also an inscription “Telact 246436 8x24” on the right prism cover. The inscription is made in block letters against the background of Carl Zeiss Tessar photo lens schematic image.
   The binocular’s serial number is “246436” and it was probably released as a 200 pieces batch in 1911.
   This device’s specimen has an interesting feature, namely the inscriptions were made with the help of silver solder at that time (1911), but not with the help of white paint, and magnification was designated as 8x (the 8x24 type inscriptions appeared later). Moreover, the binocular is perfectly preserved and has minimal signs of utilization. It was most likely subjected to later repair/restoration with upper prism covers replacement (maybe it was even remade from military model D.F.8x) directly at Carl Zeiss Jena enterprise. It is proved by inscriptions’ quality and painting neatness.   
   A very early model in Telact 8x design, but with Feldstecher 8 Fach marking, which is characterized by rare eye cup shape and narrower neck strap loops, can be checked by the following link:
   The later Telact model with rounded objective covers can be checked by the following link:
   In 1909/10, the Telactem 8x binoculars model with central focusing was released. It is available by the following link:
   In 1912 the Telact 8x binoculars were replaced by the Turact 8x model (the latter named binoculars were produced simultaneously with Telact). It became lighter and smaller than its predecessor, but worse in optical characteristics.