Top-of-the-range performance without spending a fortune? Review of Kahles Helia S 10×42 binoculars

PREMISE

On the last October visit to the beautiful Marco Lucchini's shopI was captivated by the sinuous shapes of the Austrian binoculars  Khales Helia S 10×42, It has a very well-known and somewhat nostalgic design. For this reason, given Marco's usual extreme kindness, I asked for a review model, which I had the pleasure of field-testing during the month of November. The Helia S 10×42 is currently offered at a very competitive price of 1650 euros including VAT. As always, in the article and, of course, in the video, I'll present not only the technical specifications but also my practical impressions, with video examples I took by connecting the iPhone XR lens to the binoculars' eyepiece. I'd like to remind my foreign followers that the audio is also available in English, and as has been my practice for months now, I'm also including subtitles in various languages.
Enjoy watching and reading!

 

Technical data – Kahles HELIA S

COMPANY HISTORY

Kahles is an optical company founded in 1898 in Vienna, The result of the merger of two historic Viennese workshops: the Simon Plössl Company and the Karl Fritsch optical-mechanical workshop. From the beginning, it stood out for its high quality and innovation, and as early as 1900, Kahles produced the first riflescope, a revolutionary design for its time. Thanks to the dedication of founder Karl Robert Kahles, the company laid the foundation for a long optical tradition, combining technical expertise and entrepreneurial vision.

Over the years, management passed to his sons, who continued to develop the company, consolidating its reputation as a manufacturer of excellence. Even after the difficulties caused by the war, the Kahles family managed to rebuild and relaunch the business, maintaining their commitment to quality and innovation.

During the 20th century Kahles introduced important innovations in the field of opticsAmong these, the adoption of achromatic lenses and, over time, the development of projects like the "Helia" series. As technology evolved, the company adapted and maintained high standards, becoming recognized as one of the historic names in the world of hunting, birdwatching, and observation optics.

Today Kahles operates as a well-established company, with production facilities in the Guntramsdorf area. (near Vienna), and continues to offer high-quality optical instruments, capable of combining tradition, precision and reliability — values that are concretely reflected in models like the one you are reviewing.

 

SWAROVSKI OPTIK AND KHALES

One aspect that caught my attention, and that I have read several times among enthusiasts and industry forums, concerns the possible relationship between the Kahles Helia S and the old Swarovski SLC no longer in production. To the naked eye and from the features I could observe, many mechanical and optical elements appear very similar: the magnesium body, the central bridge, the ergonomics, the prisms and the 8×42 configuration are strikingly reminiscent of the old SLC.

I must point out, however, that, As a journalist, I have no official confirmation and cannot say with certainty that these are the same rebranded binoculars. What I can say is that the visual and practical impression one gets, combined with the rumours spread among enthusiasts, leaves open the possibility that the’Helia S is at least inspired or derived from the SLC. I still think it's useful to mention this perception, because it can influence the expectations of those who observe or evaluate the binoculars, but it should be treated as a personal hypothesis and not as a given.

MECHANICS AND FOCUSING SYSTEM

The top-quality Schmidt-Pechan roof prism binoculars feature a central hinge with a well-designed 29x30 mm knurled focus knob at the top. The open bridge is wide enough to provide excellent comfort even for those with large hands (34x74 mm).

The weight of the binoculars, estimated at 771 grams with my electronic scale, It's slightly tilted toward the eyepieces, making it more comfortable to hold thanks to the reduced neck and shoulder strain required to bring the eyepieces to your eyes. The vulcanized rubber frame is thick, high-quality, very non-slip, and has a truly unassuming brown color, especially in the woods; the only brightening effect is provided by the two orange lines, which are invisible to ungulates as they see in gray.

For the rest It is a binocular that offers robustness and lightness thanks also to the magnesium hull, and which has top-of-the-line waterproofing specifications, with nitrogen filling and an operating temperature range of -25 to +55 degrees. On the side area under the eyepieces there are two very sturdy eyelets for attaching the shoulder strap.

As for the focusing system, we are faced with excellent mechanics: the movements are not extremely fluid but very precise, with an excellent snap test, that is, the univocality of the focus point which is verified by searching for the precise point, blurring in intra-focal, then in extra-focal, and trying to reach it again.

The minimum focusing distance I found on this model is approximately 3.40 meters. From this distance, I was able to reach infinity by rotating the dial clockwise for about 1.5 turns.. Obviously, these performances aren't the best in the birdwatching binoculars sector, but given that the range between ten meters and infinity requires using the rotor with little travel, I think it's definitely optimal for most nature sessions. The knob, just like the Swarovski SLC, features an integrated diopter adjustment system; simply lift the outer part towards the eyepieces and rotate it to adjust it to your needs.

OPTICS

Goals

Kahles is a bit sparing and discreet in mentioning the characteristics of the optical components used; personally, after the field test, I am quite sure that we are dealing with low dispersion lenses and also of excellent quality. Sharpness and on-axis contrast are excellent, truly top-of-the-line; in fact, we've often discussed in the pages of Binomania the possibility that a less complex optical design could lead to greater sharpness, and this is indeed the case. Color rendition is excellent, very true to life, with white tones that I find fairly neutral. Mechanically, the front lenses are embedded in the magnesium body by about 15 mm, a factor that provides excellent protection from impacts but also from stray light. I noticed that their position is also partially protected from light rain compared to more external lenses.

 
Eyepieces

 The field of view at 1000 meters is 110 meters and this results in a declared true field of view of 6.3°, which generates a wide-angle apparent field of view of 63°. The field lens is large, approximately 23 mm, while the diameter of the eyepiece barrel is truly excellent, reaching 39 mm in the area of the lens hoods: This provides excellent visual comfort, at least for me, who with an interpupillary distance of 66 mm still has 24 mm of space to "insinuate" a slightly large nose.
The lens hoods are made of high-quality materials, with soft rubber and a metal frame; they rotate with a slider system with pre-set stops. The hood is also fully removable, making it easy to clean the lenses, as is the case with most high-end products.
The company claims an eye relief of 15.8 mm and, indeed, in practice I found them very usable even with sunglasses.I would certainly advise eyeglass wearers to try on glasses before buying, if possible.

Prisms

The prism compartment is also top of the range: Schmidt-Pechan roof prisms in high quality BaK-4 glass, without evident vignetting, with a sharp field diaphragm and without the presence of scattered light near the pupil (perfectly circular) which could affect observations in the presence of stray light.

Anti-reflection treatment

Since I don't have professional equipment to test the light transmission and quality of the multi-coatings applied to Austrian binoculars, I can only share my practical impressions. I can confirm that when I looked at my face, trying to see my reflection in the lenses, the details were completely absent, a practical symptom that demonstrates how the optical train, thanks to the coatings, reflects very little. Very efficient even at dusk: tested against two top-of-the-range models of the same format, I didn't notice any appreciable differences.

 

CHROMATIC AND GEOMETRIC ABERRATIONS

 

Chromatic aberration at the center of the field

When I discuss chromatic aberration with enthusiasts, I notice a certain interest among amateur astronomers and birdwatchers, but little consideration among hunters, who seek different performance. In any case, the Austrian binoculars from Kahles have a residual color reduction that is optimal in the center of the field and which I consider only slightly inferior to products such as, for example, the Swarovski NL Pure, staying in Austria. In the common lighting conditions, in the center of the field it passed the test of the white gazebo analysis in my garden perfectly, yielding only with a small green/purple halo in the analysis of birch branches backlit against a deep gray midday sky. This performance, again, is very similar to the best binoculars on the market.

Lateral chromatism

It is noticeable, but almost always in situations of high contrast, as a slight green/purple halo on the edges of the most contrasted objects, and increases proportionally – from approximately the 65% from the center of the field – moving towards the edges.

Field curvature

Similar to the Swarovski SLC line mentioned in the introduction, these binoculars do not feature aspherical eyepieces or a field flattener. Some field curvature is noticeable toward the edge of the 80%, with a slight loss of sharpness. The very comforting situation is that, when focusing toward the edge, sharpness improves, a symptom that is not significantly affected by additional geometric aberrations such as coma or astigmatism. In daytime use, performance is still very high, partly offset by individual visual physiology, which also varies with age.

Angular distortion

As stated several times, the corner distortion is designed to avoid or reduce the "rolling ball" effect. I recommend that beginners read the Binomania glossary for further information. Personally, when observing perfectly vertical structures, I perceived it towards the 75% from the center of the field; I could roughly quantify it at around the 5%. I can't be very precise when using it in panning, as I'm not very sensitive to the rolling ball effect just mentioned.

Other aberrations in astronomical use

In star observations, the absence of aspheric lenses in the eyepieces results in the presence of non-point-like stars towards the 80% from the center of the field and a slight perception of coma and astigmatism, which are clearly evident when trying to analyze the stellar diffraction disk in intra and extrafocal.

TEST WITH USAF CHART
 

My classic, very personal test, with a target paper printed and sized by my graphic designer and which I use for a purely personal comparison, has highlighted that these binoculars, in terms of sharpness and contrast on axis, have nothing to complain about compared to a top of the range model. Sharpness is similar to that of higher-end products; it only lacks a lower containment of residual chromatic aberration, as mentioned above, but only in high-contrast situations, such as the USAF chart analysis with black lines on a white background.

 PRACTICAL IMPRESSIONS IN THE FIELD

 

Birdwatching

Kahles particularly recommends these binoculars for hunting enthusiasts; However, if we exclude the somewhat long focus from the minimum distance to infinity and a minimum distance of more than three meters, we can only appreciate it even for birdwatching observations.
The on-axis sharpness is almost comparable to the best top-of-the-line models, the contrast is high, the perception of whites is neutral, and the colors are very vivid; furthermore, they have a magnesium body and are robust and well waterproofed. If you want to own binoculars Made in Austria, from a brand owned by Swarovski but with their own production and decisions, I would say these are an excellent choice. I invite you to watch the video on my YouTube channel, since I used digiscoping to capture some birdlife at the well-known Germignaga hotspot, even in very critical lighting conditions.

Landscape

The field of view it provides isn't comparable to the best top-of-the-line binoculars, but even in this case, the features mentioned above make it a very good pair of binoculars, also compact and lighter than other solutions. For landscape observation, I also had wonderful views of the snow-capped Alps in the last week of November, which made me forget I'd left my top-of-the-line binoculars at home. 

 

Dusk

It doesn't perform as well as an 8x56 twilight lens, but the light transmission is excellent and it also benefits from a simpler optical design than an ultra-wide angle lens. In practice, fewer lenses in the optical train mean less light dispersion. At twilight, deer appear sharp and contrasty, and I struggled to find any real difference compared to a 10x42 that costs €2,500.
I think that Kahles, with this product very familiar to lovers of the “discontinued” Swarovski SLC 42, has in its catalogue binoculars for fine and demanding palates, and I see it more devoted to hunting than to birdwatching.

Astronomical observations

Point-like stars in the center of the field as in a refractor, very dark sky thanks to the high contrast and excellent brightness. Of course, with that kind of money you can buy a larger telescope, but if you bought it for your nature excursions, why not use it during your mountain hikes, with overnight stays in refuges, to observe the sky?
Last week I was in the mountains to test the performance of an astronomical telescope; although I was still a bit tired from poorly treated bronchitis, I decided to continue observing with binoculars after putting away the refractor, and I can tell you I was very satisfied. The Orion region was full of colorful stars, M42 showed little detail, while the Pleiades were stunning: bright yet very pinpoint. They appeared more similar to the low-power image of a small apochromatic refractor than to that of simple binoculars… in short, you certainly won't be disappointed.

 PROS AND CONS

Merits

• High quality optics

• Neutral colors

• Brilliant images

• Sharp and contrasty

• Lightweight and sturdy

• Comparable in many features to a top of the range model

• Made in Austria with a ten-year warranty

Defects

• Compared to a top of the range lens, it slightly loses ground in terms of chromatic aberration control in the most difficult conditions.

• It does not have a completely correct field up to the edge

• Even though it is wide angle, it is not an ultra-wide angle

• If you don't need these latter features and want to save money, the Kahles Helia is still an excellent choice.

 IN SUMMARY

The Kahles Helia S 8x42 fits firmly into a very competitive price range, confirming the excellence of the Austrian design, which has always been a benchmark in the world of optics. Versatile and versatile, while not comparable to the best top-of-the-line birdwatchers, it proves highly ideal for hunting and nature observation. The ten-year warranty and European manufacturing are also commendable, further confirming the product's quality.

 THANKS

As always, I thank Marco Lucchini of the well-known shop in Domodossola for providing the specimen for this test and for giving me the freedom to share my personal impressions in the field. I invite you to visit Marco's shop, located in Via G. Galletti in Domodossola, to try and compare the Kahles with other instruments.