This review contains a shoot-out between three rather small sized military binoculars. Apart from flawless optics, the spectrum of application of such a device asks for an especially rugged and reliable construction. The amount of research put into the design of e.g. the EDF or the BPO would usually exceed the capacities of a firm which has to operate under economical pressure. In other words, when produced nowadays and under normal conditions in a western country, these binoculars were extremely expensive to buy. It is a historical incident that, along with the collapse of the East European systems, it is nowadays possible to find them with quite moderate price tags.
Fig.1: The NVA EDF 7x40 oB. Right photo: The black circular window close to the center is required to charge the IR detector in rest position.
The EDF 7x40 was the successor of the DF 7x40 and introduced in 1981 after some major research efforts by Carl Zeiss Jena. The main goal was not so much the development of a better binocular, but one with same qualities at lower weight and smaller size. They must have noticed that the DF was a great solution for surveillance from a watch tower, but to carry the same around under combat conditions was a different matter. It was therefore opted to invest into a more compact roof-prism design, employing a split doublet objective and a five lens ocular construction. Details can be seen on Guido Thuernagel's page about optical instruments of the NVA. The EDF was built in 2 versions: The standard EDF 7x40 was equipped with a radioactive reticle illumination, the EDF 7x40 oB (oB = ohne Beleuchtung, i.e. without illumination) was without. Like the DF 7x40, this device also contains a detector for active infrared sources. The serial number of the EDF to be tested starts with 'F', meaning it was produced in 1986 - here, 'A' stands for 1981, 'B' for 1982 and so on. Today, the EDF can be found on E-bay, but not as frequent as the DF 7x40, and the price is almost twice, i.e. close to 400 Euro in good condition. Alternatively, Docter Optic, which took over the Zeiss plant in 1991, is still producing a civilian version of the EDF, which has no IR detector (units with reticle seem to be available), and is otherwise apparently unchanged and sells for about 700 Euro.
Fig. 2: The KOMZ BPO 7x30.
The Russian BPO 7x30 is still produced at the KOMZ plant in Kazan and seems to be currently used in the Russian army - at least, Russia's Arms Catalog 2000 is listing a 7x30 device, along with another 8x30 and 10x50. This interesting binocular was already described in another review and can be purchased new for about 120 Euro on Internet (see link below).
Fig. 3: The Hensoldt DF 8x30
The Hensoldt DF 8x30 was introduced to the Bundeswehr during the late 1950s, and many of them are still in use. During the early 1970s, Steiner replaced Hensoldt as the supplier for military binoculars, but their units, although optically not too bad and cheaper than the Hensoldt's, turned out to be too much prone to irreversible damages (their bodys were made of Makrolon, a high performance plastic material), and nowadays the German Army is again purchasing updated versions of the old Hensoldt line, which also includes a 7x50 and a 10x50 binocular. The DF 8x30 looks like a tuned-up civilian standard 8x30 binocular, with a rather low eye-relief of only 12 mm, unsuitable for use with gas-mask or spectacles. But it is fully water resistant, protected with a thick rubber armoring and appears to have a pretty stable prism mounting, and I have seen it taking quite a lot of abuse without getting knocked out of alignment. In another review the DF was compared to the ZOMZ Kronos 6x30 and the Zeiss Jenoptem 8x30, and here a comparison with the Zeiss (Oberkochen) Dienstglas 8x30 and the Steiner Fero-D 12 is done. This binocular can be found on Ebay for 120-150 Euro, but often in heavily used condition. In cleaner condition, but also with higher price tag, they are sold at Deutsche Optik (see link below).
Fig. 4: The BPO 7x30, EDF 7x40 and DF 8x30
The following table summarizes some of the specifications of the contenders.
|Real angle||Apparent angle||Eye relief||Exit pupil||Weight|
| ||of view (deg)||of view (deg)||(mm)||diam. (mm)||(kg)|
Image sharpness: The image sharpness of both, the EDF and the BPO, is of highest quality. During daylight observations, they are hardly distinguishable, razor sharp over most parts of the field with some image degradation only very close to the edge. Observing the night sky, however, reveals that the BPO is a little ahead of the EDF, with stars which appear a bit finer, more point-like, over the entire field except the outer most 15% of the image. Through the DF 8x30, with its wider field, the stars display a distortion already 30% away from the edge, and very close to the edge the fainter ones disappear completely. But compared to other wide angle binoculars, the DF is still on a quite high level.
Image color: The DF 8x30 provides a neutral color rendition. In contrast, the EDF and BPO show a very strong yellow tint, which can be disturbing during daytime observations. Even more irritating is that through the EDF both tubes deliver slightly different colors, with a stronger yellow through the right eye (with reticle) than through the left eye. The origin of the color is unknown to me in case of the EDF, whereas in the BPO it could be traced down to a single yellow lens element of its extremely sophisticated 7-lens ocular; see The Binofan web-page for details.
Rectilinear distortion: Most binoculars employ a slight pincushion distortion which leads to a smooth panning. The BPO is a counter example: The image is fully corrected to eliminate rectilinear distortion, i.e. straight lines remain straight all over the field, whereas, in case of pincushion distortion, they are bending inside. When panning, however, the BPO demonstrates the disadvantage which comes along without pincushion distortion: The image seems to 'roll' over the surface of a globe (see also "globe effect") . This can be disturbing at the beginning but I also got quickly used to this weird effect. There is no point to judge the quality of a binocular with respect to presence or absence of pincushion distortion: It is part of the design philosophy whether the image is free of distortion or whether the pincushion distortion is intentionally added.
Stray light: The EDF is very well protected against stray light. To achieve that, the objective tubes are wider than usual to give space for three large, razor sharp baffles which point inside toward the prisms. If stray light enters the objective lenses through a large angle to illuminate the tube walls, it is effectively blocked by these baffles. Therefore, under various different light conditions, I could rarely detect any traces of stray light which could potentially reduce the contrast of the image. Although the EDF performs very well here, it is not as good as the old DF 7x40 which, due to its particular construction with short objective tubes, was practically immune against this effect. The BPO and the DF 8x30 display a little higher intensity of stray light, but I never found it on a disturbing level.
Ghost images: If, at night, a bright object (street lantern, moon) is positioned into the field, reflections on the air-to-glass surfaces take place, which can lead to multiple 'ghost' images of the light source. Again, the EDF is performing best. There is no ghosting through the left tube, and through the right one, the reflections on the reticle remain on a very low level. Here, in fact, the EDF is clearly improved when compared to the DF 7x40. It seems that more care was taken to reduce the reflectivity of the reticle, and successfully so. The remaining reflection is so dim that it is hardly disturbing even when observing the moon. The DF 8x30 is producing a fairly bright ghost image on its reticle, but on the left eye this effect remains on a moderate level. The BPO, however, is suffering badly from ghosting. Regardless whether with or without reticle, a couple of very bright ghost images show up if the object is located close to the center. This makes observations of the moon a disgusting experience, especially because the image were otherwise so sharp that it could produce a very detailed picture of the craters. Also, brighter stars like Vega can produce an effect. It seems that here one has to pay for the sophisticated 7-lens ocular design, which offers too many of air-to-glass transits where reflections could be generated.
Low light performance: The EDF is clearly ahead of the competitors. This alone is not surprising, because with 40 mm objectives it is naturally more suited for twilight conditions than the 30 mm binoculars. But even when compared to the DF 7x40, the EDF shows a brighter image with improved contrast - the result of improved multi-coatings, and possibly supported by the yellow tint, which helps to filter the bluish glow of haze which frequently comes up after sunset. Similarly, the BPO shows more details at higher contrast than the DF 8x30. With its specification, of course, the DF has never been intended to be used as a low light glass. With an exit pupil of only 3.8mm, it was clearly designed to be a daytime surveillance binocular with high mobility. In German Army, the gap was closed with the introduction of the Hensoldt 7x50 binocular.
The 'final score' is the sum of the individual scores and is intended to serve as an orientation only. Generally, it would be an over-simplification of the matter to just look which binocular has got the highest score, because it would obscure the individual features of the devices which could differ quite a lot among each other.
Aside from that, the conclusion of this test is that the EDF is clearly the most versatile binocular among the three contenders. It is obvious that much care has been put into details in order to prevent the creation of weak points when going through the transition from the Porro-prism design of the DF 7x40 to the present roof-prism. The excellent performance not only in image sharpness, but also in stray light and ghost image suppression, the improved low light performance and, last not least, the construction which is quite compact for a 40 mm glass, indicate that there weren't many compromises allowed during design and construction of this excellent binocular. Still, this test did not lead to a bashing of the opponents, because a few points remain to be criticized on the EDF: For a high-end 7x40 binocular, the angle of field is too narrow. Whatever reason there may be for that, I had preferred to find this glass with a 60 degrees angle, even if the outer region of the field had been of lower quality. Also, the yellow image does not improve the EDF's qualities as an all-around glass. There has always been the discussion going on about whether the EDF is actually better than the DF 7x40 or not. When filling the above table, the EDF would win the image sharpness, ghosting and the general low light performance, and the DF would get the point in angle of view, color rendition and stray light suppression. In construction, it is even, so all-together they were on par. Definitely, the goal to construct a binocular which was as good as the DF 7x40 but less bulky and heavy had been reached.
The BPO has again emerged as an excellent binocular with a great performance for its low price. The weakest point of the BPO is its proneness to ghost images, but this effect won't show up in too many situations. For its price, one can peacefully take it out even on critical tours without being scared of possible damages, which are quite unlikely to happen anyway, considering the rugged design of this heavy Russian glass.
The Hensoldt DF 8x30 is, with its low weight and compact size, a highly mobile alternative to the more sophisticated but also heavier opponents. The wide field and excellent color rendition makes it a nice binocular for day light observations. When light is low, however, it is not the adequate choice. Also, the short eye-relief is an obstacle to users who need to keep their spectacles on during observation. It would be interesting to take a look at the currently issued version of this binocular, the FERO-D 16, and to check whether any particular features have been improved since then.
Docter Optics, producing the civilian version of the EDF 7x40
Lekon Service, selling the BPO 7x30
Deutsche Optik, selling the DF 8x30
Last updated: 2003