Kowa Highlander 32×82 Prominar binoculars

PREMISE

Sooner or later, anyone who owns binoculars, whether in the classic 8x42 or 10x50 format, feels an overwhelming urge to observe nature or the sky at higher magnifications. For this reason, birdwatchers typically also purchase a spotting scope that provides at least 40-50x magnification. However, the convenience and naturalness of observing with both eyes are priceless.

I, as an amateur astronomer, was already using the first medium-diameter Japanese binoculars, which offered 20x magnification, 15 years ago. I later also tried the first large-diameter Chinese binoculars (22x100 and 25x100), which, within a few years, revolutionized amateur astronomy.

However, using these inexpensive instruments, while allowing me to appreciate deep-sky objects with reasonable satisfaction, hadn't appealed to me for nature observation, where I was already using low-power but high-quality binoculars. In fact, while observing star clusters and the occasional "spot of light" is a reasonable option, for nature observation it's essential that your definitive instrument possess several excellent features, such as brightness, sharpness, a wide apparent field, waterproofing, robustness, and perhaps the ability to vary the magnification.

Technical characteristics declared by the manufacturer

Diameter (mm)	82
Enlargements	32 X (standard) 21X and 50X (optional)
Minimum focusing distance (m)	20
Weight (kg)	6.2
Dimensions (mm)	425x240x152
Kowa official price

 

For this reason, three years ago, I decided to purchase a specimen of Docter Aspectem 80-500 ED 40X, of which you can find an extensive review on the pages of Binomania.

However, in certain circumstances (birds of prey, aircraft observation and astronomical observation), I felt the lack of angled binoculars that would allow me to obtain different magnifications and consequent exit pupils to be able to adapt them to my multiple observational activities.

For these and other reasons I decided to purchase another major player in the giant binoculars sector: the Kowa Prominar Highlander 32×82.

My first encounter with Japanese binoculars proved unforgettable. Corrado Morelli, one of the first owners of these instruments in Italy, demonstrated their performance compared to a binocular composed of two 100 mm apochromatic refractors. Observing at 50X, I immediately recognized their exceptional quality. Subsequently, over the years, frequent visits to Corrado's Valtellina refuge gave me several opportunities to test them and compare them with medium- and large-diameter binoculars.

After months and months of indecision and saving, last year I decided to purchase one, which comes standard with eyepieces that develop 32x magnification and 72° apparent field.
Since I also love high-magnification terrestrial observations, I also decided to purchase a pair of TSE-9WH eyepieces capable of providing 50X magnification. To enable me to write an in-depth review, Guenter Reisner of Kowa Optimed Germany subsequently sent me the TES-21WH eyepieces, which provide 21x magnification, for inspection.

For this reason, after almost five years of “repeated tastings” and after six months of daily use, I am ready to share my impressions with you.

Mechanics and construction

At this point, we're at the highest levels. The first thing that strikes you, after admiring it and then holding it in your hands, is its weight and construction. The central optical housing is made of a single piece of die-cast aluminum, not calendered but machined from solid. A true tank. Among enthusiasts in Northern Italy, rumors circulate of a supposed hunter, fond of local grappa, who at the end of each excursion would forget his binoculars on the roof of his Jeep, only to then set off with a vengeance onto the local trails. The same sources also appear to confirm that this gentleman's Kowa Highlander has always been able to withstand the impact on the trail, and its integrity is most likely even better than the drunken hunter's guts. A brief joking aside, its construction does indeed meet military standards; moreover, its shape and construction allow for a clear comparison with the classic binoculars designed during World War II.

The binoculars are waterproof and nitrogen-filled. The integrated handle allows for easy and safe transport, while the retractable lens hoods reduce bulk and provide good protection from lateral light. The 45° prisms allow for observation of the sky without causing neck strain, while the effective eyepiece interpupillary distance adjustment system seemed reliable, quick, and free of play. Under the binoculars' body is a plate for attaching photographic plates. Removing this plate allows for quick connection to the "Center Mount" specific for this instrument (BL8J-MT). The binoculars are decidedly compact but heavy: 425x240x152 mm distributed over a weight of 6.2 kg.

JIS table. Japanese Industrial Standard

JIS-0 – no particular degree of protection JIS-1 – Resistant to vertical drop into water JIS-2 – resistant to drops of water at an angle up to 15 degrees from the vertical JIS-3 – resistant to rain falling at an angle of up to 60 degrees JIS-4 – resistant to water splashes from any direction (“splash proof“) JIS-5 – resistant to a direct jet of water (“jet resistant “) JIS-6 – water proof against direct jets of water JIS-7 – sealed against water ingress to a depth of one meter for 30 minutes (“submarine”) JIS-8 – sealed against continuous immersion at a pressure specified by the manufacturer (“submarine plus”)

 

Goals

Lenses

Two versions of these binoculars are available: with achromatic optics and with so-called "Prominar" optics made of fluorite (an artificial single crystal). The color rendition of the Kowa Higlander Prominar is slightly warm, the contrast is very high, the on-axis sharpness is incredible, and the reduction of chromatic aberration is at the highest optical levels currently permitted.

Box: Mineral fluorite and synthetic fluorite

Mineral fluorite The mineral fluorite is a monomer group halide with a hardness of 4, a specific gravity of 3.1-3.2, and a refractive index of n=1.433. It emits light when heated or exposed to ultraviolet radiation. Its name appears to derive from two factors, first from the Latin fluere, meaning to melt (since it was used as a flux in metallurgy). However, it seems that in the Middle Ages, English miners referred to it as "Flower" due to its beauty. Natural fluorite contains traces of rare earth elements that give the crystal a purplish or greenish color and, as mentioned, cause fluorescence when exposed to heat or ultraviolet rays.Synthetic Fluorite by KOWAFluorite (fluorite crystal), used in Kowa HighLander BL8J3 Large series glasses and spotting scopes TSN-883/884, on the other hand, is an artificial single crystal; for this reason, it contains no impurities and does not fluoresce when heated or exposed to ultraviolet rays. In addition to these characteristics, artificial fluorite is chemically stable, but it is more fragile than mineral fluorite and tends to scratch easily. For this reason, it is more difficult to work with during the grinding and polishing phases. However, it is possible to create large-diameter lenses that allow for excellent contrast and excellent reduction of chromatic aberrations.

The eyepieces

Both the supplied eyepieces, which develop a 32X magnification, and the optional TSE-21 WH and TSE-9H eyepieces are well-made. The attachment system, via a locking ring, is very functional and precise, keeps the eyepieces aligned and prevents accidental falls even when tipping the binoculars. The eyecup is removable for easy cleaning. If I really had to find a flaw, I would confirm that the rubber coating is very thick and suitable for an Asian face. In practice, those with very narrow interpupillary distance might have difficulty inserting their nose into the space between the two eyepieces. Personally, I solved this problem by purchasing two Baader Planetarium eyecups that fit perfectly over the edge of the eyepiece housing.

I do not recommend using them in the wild, however, as they are not as securely attached as standard eyepieces and obviously cannot protect the eyepieces as well as the sturdy standard eyecups.

 

 

Technical characteristics of the eyepieces declared by the manufacturer

 

Model	Standard 32	TSE-21 WH	TSE-9WH
Enlargements	32 X wide	21X wide	50X wide
Actual field of view (°)	2.2	3.0	1.3
Apparent field of view(°)	70	63	67
Exit pupil (mm)	2.6	3.9	1.6
Relative brightness	6.8	15.2	2.6
Twilight Factor	51.2	41.5	64
Eye relief (mm)	20	17	15
Field of view (m) at 1000 m	38.4	52.4	22.7

 

Standard 32X Eyepiece

Perfect for any occasion, it has a wide apparent field of view, equal to 70°. The eye relief is good, 20 mm, and allows use even by spectacle wearers; the medium exit pupil is suitable for all types of observation. With a 2.9 mm exit diameter, it manages to limit functional astigmatism in the observer's eyes, and the diameter is still not so small as to invasively notice floaters, especially when observing birds of prey, airplanes, or snowy landscapes.
It does not feature aspherical elements, so some image blurring is noticeable, especially in astronomical use, starting at about 75%. Total depth of field extends from about 900 meters to infinity, although subjective visual accommodation can improve this performance. It is the perfect eyepiece for long-distance terrestrial observations and for tracking fast-moving birds of prey in the sky.

 

TSE-21 WH eyepiece

The TSE-21 is my favorite eyepiece for observing deer at twilight. Thanks to the ability to observe with both eyes, the Kowa Highlander Prominar, equipped with these eyepieces, outperforms all the spotting scopes I've had the pleasure of testing, even the 100mm ones. The exit pupil is good, almost 4mm, while the apparent field of view is excellent: it exceeds 60°, placing these eyepieces rightfully in the "wide-angle" sector.
In astronomical observation, the pinpoint sharpness achievable at the center of the field is astonishing. Here too, the designers did not include aspherical elements. For this reason, image blurring is noticeable starting from about the 75-80% field.

 

TSE-9 W eyepiece

Perfect for days with little atmospheric turbulence, I usually use it in the early morning hours or an hour before dusk. It's my favorite eyepiece for observing hikers in the Alps, mountain huts, or for trying to identify birds of prey at very long distances that can't be easily seen at lower magnifications. The Kowa Highlander Prominar's ability to reveal detail at 50X is comparable to that seen with an astronomical refractor at 70-80X. This performance is due to the greater visual acuity achieved by using both eyes.

 

Beyond this factor, comfort is also a consideration. In fact, with all the eyepieces I've used, I've always been able to extend my observing sessions without experiencing any particular visual fatigue. While I usually take frequent breaks with a spotting scope, with the Kowa Highlander Prominar I can finish an entire afternoon's observing session without any problems. This is another great advantage of these binoculars.

Prisms

  Although the company doesn't disclose their construction, I believe they used the classic system of a roof semi-pentaprism coupled with a 45° parallel prism. I didn't notice any invasive vignetting. The exit pupils with all three pairs of eyepieces appeared spherical. Occasionally, some spikes were noticeable, due to the optical design of the prisms, especially visible when observing bright stars like Sirius. The field of view of these binoculars is uniformly illuminated, and with all pairs of eyepieces, the pupil always appeared perfectly circular.

 

 

Chromatic and geometric aberrations

Chromatic aberration

In focus and at the center of the field, it is practically nonexistent; you can notice a very faint green halo on the silhouettes of airliners, birds of prey, and the full moon when the image is not perfectly focused. When the image is in focus, I have never been able to notice any residual color in the center of the field. Thanks to the use of synthetic fluorite, the designers have achieved a high correction of this aberration, even though the focal ratio of these binoculars is very wide (f/5.5).

 

 

Field curvature

 Binoculars cannot be defined as instruments with a flat field. There is, in fact, some field curvature. This varies with the eyepieces and also with subjective accommodation. My older observing companions notice a worsening of star pointiformity that is greater than what a young 16-year-old amateur astronomer perceives. On average, I can estimate that the slight field curvature is noticeable starting from about 75% -80% of the field of view. Kowa itself has stated several times that these binoculars have been optimized along the optical axis.

Angular distortion

 What I love about the Kowa Highlander is its good panning performance. There's a little pincushion distortion, which allows for easy panning from right to left in practical use. The narrower the field of view, the better the reduction of rolling ball distortion.

Coma and Astigmatism 

A certain distortion of the star pattern is noticeable during astronomical observation; however, this could also be due to the neutral density filter placed before the roof prisms. This is, in fact, a solution adopted in high-quality spotting scopes and is well justified in binoculars more suited to nature observation than astronomy.
It is therefore difficult for me to specify precisely what the real geometric aberration is that affects the performance at the extreme edges of the field.

Optional accessories

In addition to the eyepieces, the following accessories are available:
BL8J-AC Aluminum Case: A somewhat expensive but custom-built case, well-shaped and with six slots to hold the three pairs of eyepieces. There's still some space on the sides, which I use for a mini-kit for cleaning the optics and to store the two Baader Planetarium lens hoods. The case weighs 3.4 kg, arranged in 340 mm x 470 mm x 160 mm dimensions.

BL8J-TP Wooden Tripod: A very sturdy wooden easel, most likely built by Berlebach and optimized for the Japanese company, in anthracite gray, extends up to 160 cm.

 BL8J-MT Center Mount Mount: A sturdy mount that allows you to directly attach the optical body of the Kowa Highlander Prominar. I haven't had the pleasure of using it extensively yet, so I can't comment on it.

Visual use

Naturalistic use

 

For prolonged, professional observations, there's no doubt that these binoculars are superior to any spotting scope; the only limitation is their weight and the obvious impossibility of carrying them in a standard trekking backpack.

As far as the observation phase itself is concerned, the naturalness of two-eyed vision, as mentioned, allows for long periods of observation without the need for prolonged breaks.

The images are very sharp and contrasty, and the reduction of optical aberrations is truly excellent. Thanks to the three pairs of eyepieces that the designers have created for the Kowa Higlander Prominar, it is possible to adapt this instrument to various observing needs.

For example, I find the use of eyepieces that provide 20x magnification essential for twilight observations of wild boar, foxes, deer, and roe deer. In this situation, binoculars provide an exit pupil of 4mm and a twilight value of 23, which is amplified by the use of two optical tubes. Various tests conducted with 95-100mm astronomical and terrestrial telescopes have demonstrated that observation through 82mm binoculars is identical, if not brighter, than that obtained with a 100mm spotting scope. Furthermore, the ability to use both eyes at twilight allows the eye-brain system to compensate for any shortcomings and to sum the information obtained from both eyes, allowing for easier recognition of more difficult details and possible subjects hidden in the undergrowth.

At 20X, the depth of field allows everything to be in focus from about 400 meters to infinity. Thanks to the smoothness of the focusing system, after a little practice, it is possible to focus with both hands while following subjects at medium distances.

 

Bird watching

The Kowa Prominar Highlander is obviously not a classic, compact birdwatching binocular, but its performance is excellent, especially when searching for very distant subjects. Using these binoculars, I've spotted numerous raptor nests (buzzards, short-toed eagles, and golden eagles), peering from the opposite valley and without disturbing the subject—a crucial factor for me.

I must admit that when you can enjoy a fixed position, without moving around the field, observing birds of prey or ungulates is unparalleled. The Kowa Highlander Prominar accustoms the user so much that, in the end, there is always a certain dissatisfaction observing with classic 8-10x magnification binoculars or a spotting scope, even if they are high quality.

At 32X and even better at 50X it is possible to admire the morphology of birds, for example, the upper wing, to verify the difference between the primaries, secondaries, and coverts or, sometimes, to check their margins. The two or more bars on the tail of a shod buzzard, for example, will appear extremely sharp when observed with the Kowa Highlander Prominar.
The term coined by the Japanese for this instrument: “Binocular Telescope” seems very appropriate.

In most cases, observing at high magnification allows us to dispel the doubts that arise from a sighting made at low magnification.

Peering through snowy woods at 50X magnification, it's a real pleasure to spot deer or roe deer hiding in their bedding, visible as small, barely identifiable silhouettes in the 10x42 binoculars. Even though I'm not a hunting enthusiast, I can understand why these binoculars are widely used in America to help hunters track prey at long range.

 

Landscape observation

What can I say? This type of observation is very varied and, above all, within the reach of most enthusiasts. It ranges from observing the landscape—mountains, lakes, clearings—to observing maritime and lake navigation, to searching for missing persons, surveying trees, and so on.

In this area, my favorite eyepieces are the standard ones, capable of 32x magnification and a wide 72° field of view. These features allow for a true immersion in the scene. Furthermore, this magnification is still very usable in the mid-afternoon, where turbulence can compromise observations made at 40-50x magnification. Even the presence of a little pincushion distortion, as already mentioned, allows for excellent panning observations (sweeping from right to left) with a good naturalness and without suffering from an obvious and annoying rolling ball effect.

 

Astronomical observation

It's well known that amateur astronomers are lovers of perfection; they love observing the stars without aberrations. In fact, when judging an instrument, overseas observers demand that it be able to display stars as "pinpoints," literally like pinheads. Indeed, aside from physiological vision problems such as astigmatism, the Kowa Highlander Prominar provides breathtaking star images at the center of the field. At 20X, the stars are similar to those observable with high-quality refracting telescopes: pinpoint, colorful stars against a very dark background. Thanks in part to the mechanical precision of the model I own (tested with a Zeiss 4X collimator and found to be well-collimated), it's also a real pleasure to search for double stars at 50X, appreciating the various color differences. It's no coincidence that these binoculars are among the most used by participants in the American Binocular Double Star Observation program. Furthermore, thanks to the extreme quality of its optical components, its ability to discern low-contrast subjects, such as galaxies, is very high, so high that I am often incredulous that it has 82 mm diameter optics.
During the winter nights I've had excellent views of the sky, and it's a real pleasure to navigate the constellation of Orion, where M42 displays various dappled details, with the stars of the Trapezium easily visible, and where M78 appears like a small bundle of light immersed in a sea of stars. The star clusters in Auriga are also beautiful, and the view of the Pleiades with the 21X eyepieces is excellent, displaying stars so pinpoint-like and a very dark sky background that they look like small gems resting on a black velvet cloth. The ability to alternate between the three pairs of eyepieces also allows you to adapt the exit pupil and magnification to the celestial object you wish to observe. For this reason, when observing the Perseus double cluster, I've always preferred using the pair of TSE-9WHs, which literally make the double cluster "explode" into dozens of pinpoint-like, colorful stars.

Thanks to the roof semi-pentaprism system combined with a 45° parallel prism, viewing the sky is comfortable, especially when using a good support. For this type of observation, I use a General HI-T tripod, which can be extended up to 2 meters in height, and a sturdy Bogen 501 HDV head, which holds these giant binoculars satisfactorily. Obviously, the prismatic design used creates greater problems than Porro prisms when observing bright, point-shaped subjects; for this reason, slight reflections are sometimes noticeable, especially when observing very bright stars or the full moon.

 

Observation of the moon, sun and planets

For this type of observation, it's helpful to use eyepieces that provide higher magnification. While we wait for the Japanese company to release new eyepieces for astronomy enthusiasts, I can confirm that at 50x magnification, the lunar surface is very sharp and contrasting. You can already appreciate various details and study the differences in albedo between the maria and the highlands. Rupes Recta is clearly visible, as are the domes of Hortensius. The perception you get is that of observing, in monovision, at least at 70-80x magnification. Jupiter displays two bands and the shadowing at the poles, while Saturn displays its ring system as a small ring. Diffuse light in this type of observation is minimal, especially considering the above.

Equipping your binoculars with a pair of solar filters makes it a real pleasure to observe sunspots on the surface of our star. Even nature lovers can begin to scrutinize the sky above us, even at medium magnifications.

 

Optional supports

 I personally use the Kowa Highlander Prominar with a Manfrotto Bogen 501 HDV head and various tripods. The Italian-made head is capable of supporting these binoculars perfectly. For an ultra-lightweight setup, taking care to maintain the legs of the lightweight carbon fiber "field" tripod, I use a Manfrotto Bogen 701 HDV, which can be used discreetly up to 32x magnification.

For astronomical use at the zenith it is essential to use the Manfrotto head in reverse to allow a high angle.

In summary

In my opinion, the Kowa Prominar Highlander is a truly unique pair of binoculars: its strengths are its mechanical quality, optical quality, and the ability to utilize at least three magnifications. I believe it to be the ultimate pair of binoculars for the discerning nature enthusiast, but it's also well suited to astronomical use.

Prices
Unfortunately, such quality doesn't come cheap. Prices are listed below (March 2013).

Kowa Highlander Prominar Binoculars (with 32X eyepieces)	Euro 6,199
TSE-9 WH eyepiece	Euro 569	(each)
TSE-21 WH eyepiece	Euro 699	(each)
BL8J-AC Aluminum Suitcase	Euro 489
Center Mount BL8J-MT	Euro 1569
BL8J-TB Wooden Tripod	pending confirmation

 

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 Disclaimer

 This review was published on March 15, 2013. Please note that the impressions of use are entirely personal and given by Binomania testers in complete freedom, without any commercial obligation or relationship and based on proven experience in the use of these optical instruments. For any information, updates and/or changes to prices, instrument features, authorized sales points or other information in general, please contact the official distributors directly by clicking on the corresponding banners.