This Russian binocular is produced at ZOMZ (Zagorsky Optiko-Mekhanichesky Zavod), a plant which has since long achieved a reputation for optical instruments like camera lenses, among others. Russian binoculars are specified by their optical scheme -- probably a heritage from Soviet times. Here, `B' stands for binocular, `P' means Porro prism, `W' means wide angle, and `C' indicates central focusing. `2' seems to indicate a successor of an earlier instrument, although I have not come across such a device yet. I got this binocular at http://www.sutter-gmbh.com/ for about 70 Euro. It was delivered with a handy soft bag, plastic lens caps and a Cyrillic instruction manual. I suggest to keep the lens caps at home since they are loose enough to get lost anyway. Also, the objective lenses of the Kronos are well buried deep enough inside the housing so that hardly anything harmful could happen to them. There are further versions of this glass in the product line, namely a 7x35, 8x40 and a 10x50, all of them with ultra wide angle and a similar price tag. They are advertised as military binoculars for sky surveillance, and claimed to be operational within a range of -30 to +45 degrees Celsius. They are claimed to be rain proof, but this certainly does not mean water proof.
The Zeiss 8x30W (left), the Kronos 6x30 (center), the Hensoldt DF 8x30 (right)
A large eyepiece and a bulky prism housing are among the features of the Kronos
The central focus is a weak point of the russian glass
The table summarizes some of the specifications of the contenders.
Angle of view: The Kronos has clearly got the widest field of view. I could not convincingly prove the huge angle of 12.5 degrees as given in the specification; but I estimate more than 11 degrees are there for sure and this is fine anyway.
Outer field performance: All wide angle binoculars are prone to stray light which is scattered from the internal boundaries of the housing. This leads to a diffuse ring of light close to the outer edge of the field, reducing contrast. This effect is most annoyingly visible in the Jenoptem. It is significantly less in the Kronos and even less in the DF. One can explain the poor performance of the Jenoptem with the fact that the housing is quite slim here; the inner tube which leads from the objective lens to the prism is just wide enough to accommodate the prism, whereas in the DF and Kronos this tube is wider than the prism so that stray light can't go straight through the optical path. This extra space is missing in the Jenoptem, leading to a slim and light weight construction, but making it suffer from stray light. Coma and astigmatism are present in the outer fields of all glasses. Image degradation is visible in the outer 20% of the Kronos and the DF, the Jenoptem is a little worse and shows the same effects in the outer 25% of the field. One should not over-emphasize such effects, however. These are wide angle glasses and the resolution of the human eye is low far out of center as well. The wide fields of all glasses allow to overview the scenery, and once something interesting happens close to the edge one will turn the glass and get it into the center where the image is perfect. In contrast to camera optics, which creates a static picture, the binocular picture is dynamic and doesn't need to be perfect up to the outer edge.
Low light performance: The Kronos has clearly the brightest image at low light, but this is not too surprising, having the largest exit pupil diameter. But it indicates that the multi coating of the binocular is well done and I suspect it is better than the coatings of the DF, which is certainly not state of the art any more. Both DF and Jenoptem perform evenly well, although the reticle of the DF can be a bit disturbing. I could not verify whether the Kronos actually shows `more' in low light. I checked with the fine structure of a tree trunk in the evening, and all glasses displayed about the same surface detail. In fact, the Kronos image was brighter, but the others had more magnification. In other words: They have better resolution, but at lower contrast. Both effects seem to compensate each other, as long as the residual light is strong enough - at a certain point, however, it is only the Kronos with its larger exit pupils which is able to display a 3-dimensional image.
The central focus of the Kronos is disgusting. It is so loose that the binocular is easily defocused accidentally when handling it around. In contrast, the focus of the right ocular is well done and without slop. Also, the inter-ocular distance adjustment feels very solid. The Kronos is the heaviest among the three binoculars, featuring the largest prism housing and oversized eyepieces. But with 0.75 kg it rests well in the hands and provides very steady free hand observations. The machining of the Jenoptem is flawless. It is lightweight but solid. The DF, being a military glass, has individual ocular focusing and is built very well and rugged and is still lightweight. It is the only water proof device among the three competitors.
The Jenoptem is optically a little disappointing, considering its proneness to stray light. But it is more compact and lighter than the military based glasses. It actually looks a bit undersized for a wide angle, and this is perhaps one key to understand its poor protection against stray light. On the other hand, being a civil glass, it is supposed to be mobile and create fun, so one may excuse some minor flaws in the image. To get one point straight: It is still much better than most of the products of this price range on the market today.
The DF is a well balanced design. Although neither optically nor mechanically on top of the world, it provides no weak point, is rugged and water proof but still of low weight and can be easily repaired. Not accidentally it had been chosen to be a central player in NATO's optical equipment for many years.
Last updated: 2003