Hans Seeger, Militaerische Fernglaeser und Fernrohre, 4.3. 4.3.1, 4.3.3; pages 323-336, 345. 4.3. Larger Navy field glasses with Porro I prisms for hand held use. 4.3.1. Developments from Germany [Page 323] Before 1914 and at the beginning of World War 1, all of the leading optical manufacturers included in their programs large bright Porro prism field glasses. The success of the Hensoldt models with 50 mm objectives was probably larger than the other optical firms suspected. A portion of the pioneering Hensoldt success was a harbinger of later military and Navy glasses. These models were the 'Marine u. Artillerieglas No. 11' with pentaprisms (1902, see fig. 67), the 'Marineglas' 12 x 50 (pentaprisms), the 'Spezial-Jagdglas' 10 x 50 (introduced 1904, pentaprisms, center focus), and the first 50 mm Dialytes (12 x 50 'Marine' and 10x50 'Nimrod II' both 1905, available only with center focus). Zeiss followed with a 50 mm objective, the Noctar, circa 1910, see fig. 196. The Hensoldt Pentaprism models and Dialytes, and the Noctar, have a roof prism system, which at that time was easier to use with a large objective, for optical reasons (see 'Feldstecher', page 139). Because of the complicated and therefore expensive roof prisms, and surely also because of the patent situation, these prism systems had only a limited usage (at the time there were only two manufacturers), and the time was ripe for high performance Porro I field glasses with large objectives. In the beginning their acceptance was slow, and there was still experimentation with the construction form. The first large Porro I hand held field glasses might have been the highly unusual Navy glass by Leitz, introduced circa 1908 (?), see fig. 218. This 12 x 60 glass, with good optical quality and a new form, was not part of the civilian Leitz program. It can therefore be supposed that the Leitz 12 x 60 was mainly or exclusively built for the Navy.* *Recently, a 12 x 60 without Navy markings has surfaced. This one came from the estate of Dr. Ernst Leitz and could have been a special production. It was probably not only the first hand held Navy glass with 60 mm objectives, but also the first field glass for hand held use, which was built with this objective diameter.** **The 'Dosenfernrohr' [tin can telescope], an in-line monocular telescope with tripod by Zeiss, from 1898/99, used an in-line ('straight-sighted') roof prism, patented by Zeiss. This important development was not further pursued, until it was taken up again with the Noctar. Besides the depicted Leitz model, there were two smaller Porro I Leitz field glasses with a similar form, the 10 x 42 and 12 x 42, but none have survived that are known to the author, so it cannot be verified if they had the markings of the Imperial Navy. These models are not as elusive as the 12 x 60. They first appear, with individual focus, in the civilian brochures from Leitz (1912, and perhaps before. Around 1914, both models were available with center focus. After the first World War, these glasses with their unusual form were no longer in the catalogs. Before that, the Porro I 12 x 60 (and also its smaller 'brothers') was replaced in the Imperial Navy by the Leitz Porro II models, shown in figures 197 to 200. We already mentioned the American prism field glasses of Bausch and Lomb, with their characteristic form, probably derived from the German Terlux models of Busch, Rathenow (10 x 45, fig. 28). Though the use of the Terlux models by the German Imperial Navy cannot be documented, they were very popular in the British Royal Navy: 'Busch Terlux are by far the best glasses I ever used' pronounced the English Admiral Lord Charles Beresford, as noted in a Busch prospectus of1913. In 1912, another Busch prospectus contained the following glorification by the Geheimer Regierungsrat Dr. A.M. from H.: 'The 10 and 8 power Terlux prism binoculars have always served well on the bridge, and especially the 18 power model is almost constantly used, because of its great magnification, yet great sharpness and exact focus...the original apprehensions, that it could not safely be held by hand, proved utterly erroneous. In the hand of the experienced observer, it is quite usable, even from a rolling ship. This glass is often used by the officers of the ship, as well as by all members of the expedition, even His Royal Highness the Prince of Prussia, and is much praised.' The above mentioned Leitz Porro I models with their unique form, along with the Bausch and Lomb 10 x 45 and the Terlux models, soon disappeared from the Navy and from voyages at sea. Other glasses, which resembled in the form the Zeiss models built since 1893/94 took the predominant place in the Navy, and gradually pushed the other designs into the background. [page 324] The Porro I models discussed here have one characteristic in common: the distance between the objectives is greater than between the oculars, covered by the well known Zeiss patent until 1908. Most of these marine models were built with large objectives (for brightness), and there soon developed two different construction forms. Some of the marine models have a lengthened prism housing (for example the 6 x 42), and others have a relatively small prism housing, but lengthened objective tubes.( 7x50) At the beginning of the first World War, Voigtlaender had already produced two models with brass housing covers leather coverings, and the lengthened objective tubes, a 6 x 42 and a 7 x 50. Some surviving specimens are engraved with the Imperial crown and M, see fig. 219. The popularity of the Voigtlaender 7 x 50 may be explained by the fact that Otto Weddigen, legendary U-Boat commander of the U-9, awarded the Pour le Merite in the first World War, might have used this glass.* Busch, Rathenow, also made at that time similar 7 x 50 models with Porro I prisms. (*The field glass in question was offered to the author, along with an engraved pocket watch and a two cornered hat, some years ago. The field glass had the imperial crown and a more recent engraving: 'To the Commander of U-9'. Without any doubt it was from circa 1914. In the meantime, another field glass surfaced with the inscription 'Weddigen' and 'U-9', this one a Fernglas 09, see fig. 9. These engravings are also probably of a later date, probably after the time of the first World War. At that time, the original glasses from the first World War were still available and names like 'Weddigen' were compelling. The esteem of a famous personality led to the 'revaluation' of some field glasses by appropiate engravings; and the author is convinced that he will soon hear about further 'Weddigen' field glasses. For two reasons similar forgeries did not take place after the second World War. The military achievements of German war heroes were and are passed over in silence, and infrequently register in the conscience of most people. Also, the corresponding field glasses did not exist, or existed in very small numbers after the second World War, so that the forgers did not get the opportunity to engrave U boat glasses with the names of German U boat commanders of the second World War. Unfortunately the forgers have now recognized this 'hole in the market'; in several places in this book we have had to point out forgeries. Several times the author has refused to let certain persons have a U boat glass, thus saving the glasses from carrying a forged engraving. It must be said again, and emphatically: an original field glass without engravings is always 100% genuine and unfalsified. A field glass with an engraved name, or other non-official engravings, is with high probability a forgery, except when the 'history' of this glass can be traced without gaps, and documented to the first owner or user.) A special developement came from Berlin; Goerz produced a huge field glass in the usual Porro I form, with the specification 8 x 56, a combination of magnification and objective diameter, which was not used after that for a long time, but has a new popularity in the last few decades. This wide angle glass, shown in 'Fernoptik' of 1921 (v. Hofe, page 140) appears here in fig. 220, and was called 'Marine-Nachtglas', an indication of its use. The surviving specimens were probably built after the first World War (the serial numbers are greater than 500,000); but it is highly probable that these military field glasses had already been developed and probably also built during the first World War. This glass could have been the first wide angle model from Goerz, referred to in the priority argument in 'Feldstecher' (page 74). (An 8 x 56 prism field glass had already been already built by Voigtlaender in 1910, but as a monocular. See also the Leitz prototype 8 x 56 wide angle in fig. 97) This 'Marine Night Glass' from Goerz was probably an experimental model or prototype, for it is too 'unhandy' for common use, there are no fasteners for a carrying strap in the depicted model, and neither is there a device for attachement to a tripod. This glass did not succeed. In the history of Goertz field glasses we do not find another similar Navy field glass with Porro I prisms, and in the catalogs for civilian Goertz glasses, which the author has had access to, the Marine-Nachtglas 8 x 56 is not mentioned. (After the first World War, Goertz produced a civilian 15 x 60 with center focus, for hand held use.) The picture in 'Fernoptik' (1921), by the Goerz colleague v.Hofe, shows that in the time after the first World War, this glass was considered an outstanding achievement, and even as a 'flag-ship' of their field glass program. A Goerz 'Fliegerglas' [pilot glass] 6 x 60 is mentioned in the footnote in section 4.2.2. Other unusual models with Porro I prisms include the 6 x 42 model by Zeiss (see fig. 58 and 221), which also has the characteristic Navy marking ('M' and crown) from the time of the first World War. [page 327] It has the same magnification as the proven 6 x 30 model but the geometrical intensity of light of a 7 x 50 glass. Another glass, with an even higher geometrical intensity of light than all other field glasses in this book, is a special model by Zeiss. This field glass is not in the catalogs from the time of its inception (about 1915). This 4 x 42 Porro I field glass is shown in fig. 221. With these specifications, the exit pupil has a diameter of about 10.5 mm, probably largest exit pupil in a field glass for hand held use. We can only guess at the intended use for this field glass, it has all the characteristics of a military model, and perhaps it was destined for use on boats or in planes, or perhaps it was only a factory modification of a military model for civilian use, see the text for fig. 221 and section 2.3. The years of the first World War, especially the last two (1917/18), were a time of shortages and ersatz economics in Germany. [page 328] Even the Imperial Navy had to live with compromises and make do with what was still available. A surviving D.F. 6 x 24 (Zeiss, Jena) with the serial number 949600, made of zinc, shows an M and a crown, and was therefore produced in 1918 and still used for the Navy. The most successful Navy glass was produced in Jena at the beginning of the first World War: the D.F. 7 x 50, and the later civilian form with individual focus 'Binoctar'. This field glass was available only with individual focus for 15 years after its inception, an indication of its intended use in the military and Navy. Only in 1930/31 was the model offered with center focus, as the 'Binoctem', which could be as useful to the hunter in the forest and field, as to the naval personnel at sea. [page 329] The 7 x 50 Porro I models were successful and popular, and became a classical form, which was followed by many excecutions, variants and different special models, not only at Zeiss but world wide. This combination of magnification and objective diameter results a pleasingly large exit pupil of 7 mm diameter. This delivers a bright image that is completely usable by younger people. It facilitates observation aboard ships, on vehicles, and from airplanes, because during movement the object is not so easily lost to sight, in other words the object does not so easily escape the limits of the field. The weight of the special models for hand held use, is usually between about 800 and 1200 grams, and is therefore not unpleasant or overpowering. The optical quality is generally good, the production of the 7 x 50 optics is obviously not too difficult. Daniel Vukobratovich from the Optical Sciences Center, University of Arizona, noted in 1993/94 ('Binocular Performance and Design') concerning the need for less than fully corrected 7 x 50 models: [page 329, text in English] [page 330] An earlier D.F. 7 x 50 can be seen in fig. 222. A rich history can be read from the engravings: In November 1918, it was in service of the German Navy (?), in 1935 it reached Austria and continued its service there in the wartime Navy. The glass was taken to England (booty or confiscated after 1945?), to be purchased by a very pleased new owner in the 1970s, who purchased it for 15 pounds sterling at a flea market. Why this history? If the glass were offered in an auction more than ten times the price, the provenance of the markings would be highly suspicious. They are easily engraved later, which forgers have unfortunately recognized. Over the course of time, the 7 x 50 went through the developments seen in other service glasses. The Zeiss models retained the use of aluminium (body), zinc and brass as the predominant materials through W.W.I. In the thirties, aluminium became more established for all metal parts, and the field glasses become lighter. Leather and hard rubber coverings disappeared over time, and the German military and Navy models had a black, more or less thick laquer. A coarse lacquer was used before the first World War (Fernglas 09, see fig. 9, and some Hensoldt models). Leather replaced hard rubber at the end of the first World War, because of the shortages of rubber. Note: German military models, especially from Zeiss, with housing covers of zinc, (some with body of zinc), and with leather cover, are typical for 1917/18; there was a shortage of rubber during the first World War in Germany. In the years before 1917/18, another covering for military models was a woven fabric that was lacquered with black paint. There are also field glasses from 1917/18 with a cover of thick black paper, but these are rather rare. The desire to beautify these interesting but most unattractive models, has caused some unsophisticated collectors to cover these models in leather. The uniqueness of such a glass is therefore destroyed, with its original condition, and again a valuable piece is irrevocably falsified and devalued. [page 331] In 1935/36, Alexander Smakula (Zeiss, Jena) developed the lens coating, a reflection reducing coating for optical elements. For all optics, especially thoise with numerous surfaces, the coating (also called 'blue coating') is a valuable means to increase the transparency and therefore the brightness of the image. In the marine optics, the coating was especially useful. U-boat periscope optics were the first to receive this new coating, along with the Navy field glasses. In Germany, Navy optics and tank aiming field glasses were the only items manufactured with coated optics; and other German military models usually didn't have coating (and when it is there, that nearly always means it was applied later, and the original condition is falsified.) For military optics from the U.S., Great Britain or Canada, the sequence is similar to the one in Germany: Marine optics were the first to receive the blue coat, but only during the course of the war. In chart 2, we can see that in the U.S. in 1944, coating of military optics was quite common. At least 5 of the listed models are coated, and since one model is 'not coated', it is therefore more of an exception than the rule. In Germany, the value given to the coating process can be deduced by the fact that it was immediately declared secret. Coated models are (most often) marked with a T (= transparenzbelag) [transparent coating] The typical T-coating was not cleanable, and through the required cleanings, the exposed surfaces were partly rubbed off, and the optics rendered less effective. [page 332] Towards the end of the war, the 7 x 50 U boat glass (fig. 255) had a blue red wipeable hard coating. As with all arms and devices of the military from 1941 on, the glasses of the Navy were also marked with a code instead of the name of the manufacturer, see paragraph 2.3.4-VI In the time before the second World War, and even more during the war, several construction forms or variants of the 7 x 50 were produced. The main danger at sea was the hazing of the optics from the intrusion of humidity, and this was countered with a built-in dessicator cartridge. These cartidges contain silicon gelatin in granule form as a water absorbing medium (one of the trade names was Silicagel). Silica gelatin is a pure silica acid with a highly active surface, which is so large (porous) that water or steam can be absorbed in an amount that can be a quarter of the weight (for more active kinds) up to a third of the weight of the silicon gelatin (citation from the manufacturer’s paper: 'Fungus - recommendations how damage by fungi... in optical devices can be avoided, Zeiss, Oberkochen 1967). Fig.223 shows a freqently seen variant of the Zeiss 7 x 50 Marine model where the bottom covers of the prism housing have such a cartridge screwed into them. The ocular of this model has the usual construction form. [page 333] Equally common are the 7 x 50 models with 'arrangement for use with gas mask', see fig. 224. The special ocular construction of this glass is recognizable by the hard rubber ocular covering, attached to sliding rings. The exit pupil is longer in this model (which does not have a drying cartridge), see 'Feldstecher', page 125/26. By pulling out the ocular sleeve, the best observation with the naked eye is achieved. When using a gas mask, the ocular sleeves are pushed down, and the eye can then approach the exit pupil. As mentioned in section 2.5, the Zeiss 7 x 50 models with gas mask oculars were also used for anti-aircraft defense, and perhaps by the Navy. Surviving models are marked 'M IV/1' and 'T', and with 'Flak.(Kueste)' [coast] or 'Scheinw. u. Fluwa.' [searchlights and anti-aircraft arms'. Field glasses of this kind might have been used with anti-aircraft search lights, for there are pictures from W.W. II showing field glasses which are mounted on a horizontal strut next to the searchlight. Another Kriegsmarine 7 x 50 from Zeiss, is similar to the usual Binoctar, it is a 7 x 50 with neither desiccator cartidges nor gas mask oculars. This relatively rare glass in shown in fig. 225. An unusual German 7 x 50 field glass is shown in fig. 226. It is a fixed focus model. the oculars do not have any screw threads for focusing. This characteristic indicates use in a military airplane, but the coating indicates use in the Navy. We can only speculate about the exact use, or area of use during the war. These German military 7 x 50 fixed focus models are rare, the auther knows of only the two depicted examples, both from Zeiss. [page334] Only a few specimens survive of another German 7 x 50 model from the Kriegsmarine. This is a model with eyeguards that can be folded to the side, which permits easy cleaning of the eye lenses or use with glasses or gas masks. The model in fig. 227 (top) is furthermore distinguished by an ocular lens which sticks above the housing by about a millimeter. These two characteristics can also be found in the U-boat glass of fig. 254. There were accessories for the Navy 7 x 50s, but only photos survive. Frequently these glasses were protected with a rubber covering, which was pulled over the housing, see fig. 228. The rubber was sensitive to sweat from the hands, fat and oil, and it soon became sticky, disintegrated and lost its durability. Today no (?) example of this accessory survives. A practical accessory for this and other German Navy glasses from W.W. II are the special ocular covers, called 'Benutzerkappen' [usercaps], which are held by a rubber band (see figures 223, 224, 226, 227, 253, 255, 257 and 259). When using the glass, the rubber band in the cap can be laid into the holding device made for it, which sits on top of the folding bridge. This holding device is not present on all examples of the models on which it was used. This practical method for fastening the 'user caps' to the glass, and the holding device for it, are probably all but forgotten now, as are other practical devices shown in this book. [page 336] This device is the best way to securely protect the oculars of a field glass, along with the spring-fastened cover, used for the old D.F. 03 (fig 49). The objectives of 7 x 50 models were often protected against blows by rubber rings fastened to them. A field glass is only truly complete with the original case. The case for the 7 x 50 with gas mask oculars can be seen in fig. 224. This case contains further accessories, such as glass filters which can be attached on top of the eye pieces. Military binocular cases often have stamps with the manufacturer’s marks, either written out or encoded, often with the year of production, and sometimes stamps with national emblems and the marking: Wa.A (inspection stamp of the corresponding army armament department, usually with a three figure number). Some field glasses which were especially well restored and falsified, are only identifiable as military glasses by those unassuming stamps on the case. The 7 x 50 Zeiss models described above are similar in appearance to the Binoctar. They were the most important glass for the Kriegsmarine, but not the only one. Other producers probably delivered similar glasses to the Navy, but in lesser numbers, and very few examples survive. Because the differences between them and the Zeiss model in fig. 225 are minimal, further descriptions are superfluous. 4.3.3. Further developments from Germany. [page 345] In 1932, it was decided in Wetzlar to construct an 8 x 60 field glass. This magnification had already been used for 15 years by the Naval air defense, but there was no light weight civilian version. This model was developed at Leitz, in a group of field glasses of the usual Porro I form, called 'Spezial und Grossfeld Glaeser fuer Jagd, Luftfahrt, Marine' [Special and wide field glasses for hunting, air travel, and marine]. In a 1932 civilian brochure, the specifications were 8.3 x 60. Along with its 'sister model', the 12 x 60, it was then the largest civilian field glass with Porro I prisms for handheld use, see fig. 97 in 'Feldstecher'. (The already discussed 15 x 60 Goerz model was no longer produced at that time, and the Zeiss D.F. 15 x 60, see fig. 98, is not a hand held glass.) In 1937, a Leitz 10 x 60 was added, with the same construction form, and very soon it decorated at any suitable opportunity the uniforms (densely festooned with medals and ribbons) of the Reichs air minister. The Leitz 8 x 60 and 10 x 60 glasses are therefore still known as the 'Herman Goering glass'. The Navy made use of it as well, and consequently we soon find the glass with the Naval insignia of the third Reich, see fig. 233. But it was not as important as the Porro II 8 x 60 models, and the 7 x 50 glasses, in spite of its great optical sharpness. Perhaps the smaller field of view was considered a disadvantage. Before we come to the submarine glasses, let us consider the large fixed glasses of the navy. More detail on these models is described by Kevin Kuhne in section 3 , also see Gould 1975. 7