Swarovski’s 42mm SLCs are their ‘entry level’ birding binoculars, but they’re still expensive. Are they worth their lofty price tag, or are you just paying for the name? In this review, I put them to the test to find out.

Swarovski 10x42 SLC HD Review

Swarovski don’t really do budget binoculars, even in the way Zeiss do with their Conquests, let alone Terrors (sorry, Terras). Personally, I think that’s a good marketing strategy. I’m dubious about a Porsche hatchback and I feel the same way about Chinese Zeiss.

So, despite being their entry line, the SLCs are still resolutely Made in Austria, with all the quality, serviceability and reparability that implies. As we will see, though, the SLCs are not just a second-best Swarovski for those unwilling or unable to afford a pair of ELs. Rather, they are just a more traditional take on a similarly premium binocular.

Here I’m testing the 10x42 model because it’s a size that’s quite useful for astronomy as well as birding. I have previously tested both the 10x56 and 15x56 models.

At A Glance



Objective Size


Eye Relief


Actual Field of View

6.3 degrees / 110m at 1000m

Apparent field of view

61 degrees

Close focus








Data from Swarovski UK

What’s in the Box?

Design and Build

The SLC range is Swarovski’s second tier of binoculars behind the EL range, but they’re still priced and built like premium. The main difference seems to be a more conservative body style and the absence of field flatteners. The pay-off is that these 42mm models are smaller and lighter than their EL equivalents.

The SLC range has been through several versions over the last twenty years and this latest one has been equipped with HD lenses to reduce false colour fringing. In fact, the larger SLC models have only recently caught up in this respect, some years after HD lenses were introduced on the 42mm models.

At one time the SLC range embraced all objective sizes from 30mm through 42mm and 50mm to 56mm. Now Swarovski only make 42mm and 56mm SLCs; the 30mm and 50mm models have gone.

Body and Ergonomics

The SLC have a conventional body with a slim bridge and longish barrels, unlike the open bridge of the EL range. The body has thumb indents sculpted into the back.

Swarovski don’t make much of the light weight of these SLCs, but it’s real – lighter than most current premium 42mm binoculars and matched only by Leica’s Ultravid HDs. At just 765g, these are 30g lighter than the 8x42 SLCs (yes, really – I checked with Swarovski) and 75g lighter than the 10x42 ELs and Zeiss’ 42mm HTs. Part of the reason for this light weight is that the body is magnesium, rather than the aluminium used in previous SLCs.

They’re not just lighter. At 144mm long, the 10x42 SLCs are shorter than almost any other premium 42mm model and they are very slim too. In the photo below you can see that they’re more compact than Zeiss’ old 7x42 FLs which were the most compact of that series and much more compact than the replacement HTs. I was genuinely surprised at how small these 10x42 SLCs look and feel.

The SLCs’ armour is different from the ELs’, both in texture and colour – it has a more leathery pattern to it. But it’s equally comfortable, grippy and un-rubbery.

These binoculars, like all recent Swarovskis, are fully waterproof to several metres.

Swarovski 10x42 SLC HDs are even more compact than Zeiss’ shortest 42mm Victory FLs, the 7x42s.


The look, feel and precision of the focuser are similar to any other recent Swarovski, which is to say first rate, if a little heavy. Occasionally there is a trace of scratchy stickiness, but that’s true of almost every greaseless design and typically improves with use. Otherwise focusing is really good – smooth and precise with no free play. The focus point is exactly the same focusing in and out and there’s no hint of tilting or slop in the optics when focusing.

The focuser is quite slow for a birding binocular though, taking just over two turns from close focus to infinity.

One slight oddity is that the focuser only goes a very little way past infinity, so there may not be enough extra focus to accommodate some people with strong prescriptions. If that sounds like you, try before you buy!

The dioptre mechanism is again like any recent Swarovski, and my personal favourite. You pull the focuser wheel to reveal a scale. Moving the wheel then adjusts the dioptre in click-stops of a quarter. It’s an ideal mechanism – smooth and foolproof. You could simply dial in the difference in your prescription if you know it.

Pulling the focuser wheel reveals a scale; turning it then adjusts dioptre in quarter click-stops.

Optics - Prisms

Unlike the 56mm SLC HDs, the 42mm models make do with conventional Schmidt-Pechan roof prisms, rather than high-transmission Abbe-König prisms. Their overall percentage transmission is thus down slightly on the larger models, even though they do have SWAROBRIGHTTM dielectric mirror coatings.

Optics - Objectives

The SLCs’ objectives contain elements made of high-fluoride glass that allow Swarovski to claim them to be ‘HD’, or ‘High Definition’. You might well ask why. The answer is that high-fluoride glass elements improve the view in two ways:

1)     Lenses with HD elements improve definition by reducing the blurring effect of false colour fringes on high-contrast parts of the view.

2)     High-fluoride glass scatters less light, leading to improved contrast and resolution.

Swarovski apply their best coatings to the SLC HDs: SWARODURTM and SWAROTOPTM. These coatings have the pinkish hue of most recent high-end models and give the SLC HDs an excellent (for their type) transmission of 91%.

The SLC HDs also get the SWAROCLEANTM coatings that shed water and dirt from the lenses, making them easier to use in heavy rain and to keep clean.

You may have noticed that Swarovski use another trademark for the premium ELs that these SLC don’t have: SWAROVISIONTM. This is not a specific coating or technology, but rather the combination of field flatteners, high eye-relief eyepieces and HD lenses, so the only feature these SLCs really lack is the field flatteners. Interestingly, though, the SLCs’ coatings do look different from several pairs of ELs’ I have tested.

The barrel internals aren’t knife-edge baffled in the way the ELs’ are. Instead, the focuser lens just floats in a cage which incorporates a single baffle whilst the barrel inside is blackened. The internal quality of castings and finish looks just a little rougher than the ELs’.

Swarovski’s pinkish coatings now look just like Zeiss’ T* coatings.

Interior construction looks a little rougher than the ELs’, lacks their ridged micro-baffling.

Optics - Eyepieces

The eyepieces look to be a modern design with deeply concave, large (22m diameter) eye lenses.

For once, eye relief, as measured from the rim of the eye cup, measures at spot on the claimed 16mm. This means that I can see most, but not all, of the field with my chunky specs on.

Spherical aberration of the exit pupil, which causes momentary blackouts as you move your eye around in some binoculars, is virtually absent.

The eye cups are standard Swarovski and so of the highest quality, but they only have two extended positions, not the three of the ELs’.

Eye cups are Swarovski’s usual premium items, but have just two extended positions.


The 10x42 HDs come with the usual Swarovski accessories – the semi-rigid field case with a separate accessories compartment, band-on objective caps, a width-adjustable eyepiece cap and their premium strap. All just like the previous generation of ELs’ accessories, in fact.


The 10x42 SLCs get the 32mm sized field case.

Accessories are typical Swarovski and much the same as the pre-FieldPro ELs’.

In Use – Daytime

Ergonomics and Handling

I’ve noted that these SLCs are very slim and lightweight. That makes them easy and quick to handle. I found them comfortable and convenient to hold too, but the compact size may be a problem if you have large hands. I couldn’t get my hands all the way around the barrels. Paradoxically, I found Zeiss’ much larger Victory SF 10x42s, which I was reviewing at the same time, easier to hold.

The armour has a nice feel and the thumb-indents help them feel secure in the hand.

Decent eye relief, high-quality adjustable cups and lack of blackouts give these SLCs a high level of eyepiece comfort. Eye relief may not be quite enough to see the whole field with specs on, but these are generally comfortable and good to use with glasses.

The focuser and dioptre mechanisms are close to ideal, but I found the focuser a little slow when trying to catch birds on the wing. The focuser wheel naturally falls under the right forefinger when holding with my thumbs in the indents.

Their small size and elegant design make them unobtrusive to wear, a positive attribute for casual and travel use when you maybe don’t want to be shouting, ‘Birder!’ or ‘Tourist!’

SLC HDs are comfortable for small hands and work well with glasses.

Swarovski SLC HDs are one of the most unobtrusive 42mm binoculars to carry.

The View

Centre field, the view through these is close to the very best, ELs included: sharp and with that crystalline clarity you only get from the finest binoculars. Resolution, contrast and detail are supreme and you can pick out every tiny detail from the aberration-free view. Brightness is excellent, but noticeably just a touch less than the ELs’ during the day.

Focus snap is outstanding and the focuser precise enough to cope with it. Optical fabrication quality, as usual for Swarovski, is very high.

Depth of field is good, but a touch less than the ELs’.

Colour rendition is neutral and similar to the ELs, but perhaps a bit warmer.

Overall, the view really doesn’t give away much to the ELs’ – just a little narrower, a touch less bright and deep, less clear towards the edge, but we are talking very small margins of difference here.

Flat field?

We’ve established that these SLCs have an on-axis view of the very highest quality. If we are to find significant differences from the premium ELs, it’s further out that we have to look.

Unlike an EL, which is almost flat (and certainly completely usable) to the edge, these have some off-axis field curvature and a trace of distortion and astigmatism too. This curvature starts gently at about 70% and only becomes significant by 80% (yes, I’m nerdy enough to spend time viewing a ruler!) Unlike some Zeiss’ binoculars, the field is still very usable right at the edge, though.

Overall, field curvature during the day is mild and not a problem.

Chromatic Aberration

Centre field, chromatic aberration correction is very good, especially for a 10x binocular. Even silhouetted branches and the birds roosting in them show just a trace of false colour fringing. Only the very best designs with two ED elements (e.g. Kowa’s Genesis XD models) might better these for correction of false colour and by only a small amount.

That last 20% of field width, which has some curvature, does also see an increase in false colour too, but it’s still much better controlled than at the field-edge of the Zeiss Conquest 15x56s I tested recently.

This lack of false colour fringing may not sound like a big deal, but if you want to view birds on the wing, or high in branches, it does make a big difference to both the aesthetics of the view and the resolution.

In Use – Dusk

These have excellent, but not exceptional, dusk performance, perhaps due to the slightly lower levels of transmission than the very best. They certainly work well into low light conditions, better than any 32mm binoculars, but don’t quite have the ‘light intensifier’ effect of my 7x42 Zeiss FLs.

In Use – The Night Sky

Stars are superbly sharp on axis, but start to become mildly comatic in appearance from about 70%, due mainly to field curvature with just a bit of astigmatism. The only problem is that this gives a slight ‘tunnel’ effect as field-edge stars in rich star-fields blur into a mist.

Focus is very snappy and precise on the night sky and the view nicely relaxed. The low weight is appreciated when holding these up for long periods. I found myself tending to hold them around the barrels, but they are too close to easily get my hands all the way around.

Control of stray light is very good. There is no flare or spiking on a streetlight or bright Moon in-field and only a very faint field-edge ghost. The deeply-recessed lenses control veiling flare, with a bright light outside the field, very well too.

Contrast is excellent, making the most of the aperture on fainter stars and deep sky objects.

The Moon

The 10x42 SLCs gave a very sharp and contrasty view of the Moon, with no flare or false colour to spoil it.


The Jupiter test was perfect, showing a clearly defined disk and no smear or spiking – one of best I’ve seen. Jupiter’s subtly creamy colour was very well delivered. The Galilean moons were shown as very tight, bright points – you could easily use these binoculars to track their daily movements, even close to the planet’s disk.

Deep Sky

I was lucky to get a couple of dark, clear and Moon-less nights with the Swarovski 10x42 SLC HDs, despite the horrid wet and cloudy winter we’ve been having, so I was able to thoroughly test them for deep sky performance.

The Great Nebula in Orion, M42, was bright and sharply defined, with clear arms and central spike and the cut-off to the dark lane behind the main area of nebulosity very apparent.

The field was wide enough to fit both Orion’s sword and belt in, but doing so left Mintaka at the far right of the belt and Nair al Saif at the bottom of sword quite comatic, which they weren’t with the flat-field ELs.

The Auriga clusters, M36 and M38, resolved into stars with some averted vision, their characteristic shapes of pinwheel and starfish very evident – proof of very good contrast delivery, thanks to those pin-point stars. M35 resolved easily too.

Sirius showed no nasty false colour or spikes, just a dazzling bright white and scintillating point as it should be.

I found Bode’s Nebula easily, its component galaxies bright and clearly different in shape and size. M33 was easy to pick-out too, even low in the sky. I noticed that fainter galaxies were harder to find than with larger apertures and I failed to find M96 in Leo, which is easy with 10x50s (though some sky-glow from across the bay wasn’t helping).

The Double cluster looked really good, with lots of diamond-dust stars and some nebulosity in the nearby Heart nebula. Other open clusters – M41 in Canis Major, NGC 2244 in the Rosette Nebula and the Beehive – looked well-populated with bright and sparkly stars too. I managed to pick up a trace of the nebulosity in the Rosette Nebula.

I easily picked up M1 – the Crab supernova remnant - with a bit of averted vision.

Overall astronomy performance was excellent – I didn’t want to stop using them and write up this review!

Testing the 10x42 SLC HDs under a dark winter sky.

Swarovski 10x42 SLC HD vs Swarovski 10x42 EL Swarovision

A valid question that you may well be asking is whether the more expensive EL model is worth the extra cost. I’ve compared these SLCs with the ELs throughout this review, but a summary of their relative strengths and weaknesses follows:

·        The ELs are longer and heavier: these SLCs are particularly small and light for a 10x42.

·        The ELs have a more upmarket look with their exposed metal in the bridge and different armour, but basic build quality –optical and mechanical – is much the same.

·        I found the open-bridge design of the ELs a bit easier to hold.

·        The ELs have a couple of millimetres more eye relief (not the four millimetres the brochure suggests) that makes them a little more comfortable with glasses.

·        The focuser action is very similar, but the ELs’ focuser is much faster, making it easier to focus onto birds on the wing.

·        The centre-field view is very similar, but the ELs have a slightly flatter, brighter, deeper field of view.

·        The ELs’ flatter field isn’t that noticeable during the day, but makes them nicer for astronomy.

·        In theory, the ELs are about £700 more expensive, but discounts often reduce that gap to £400-500.


I really like these 10x42 SLC HDs – another Swarovski winner for me (and no Swarovski don’t give me incentives, or even loan me product to review).

These are emphatically not a cut-price model. Unlike a pair of (admittedly cheaper) Zeiss Conquests, nothing here departs from Swarovski’s super-premium brand values. The overall build quality and view is much the same as their top-line EL models. The only obvious de-merits are a bit less eye relief and a slower focuser. Close inspection reveals a bit more field curvature and just a little less brightness and depth of field, but you probably won’t notice much difference in use. Otherwise it’s all familiar Swarovski – crystal clear, sharp, high-resolution and snappy focus.

Compared to the ELs (and indeed most other premium 42mm binoculars) these SLCs do have one superlative feature, though – their compact size and weight. Given the great view and excellent build quality, that alone might swing them in your favour: they handle more like most 32mm bino’s. So, a pair of these could work well for birding, astronomy and travel. For many people that flexibility alone might justify the cost of a premium brand. It’s just a shame that I couldn’t really find any very cheap deals on these, you’re going to have to pay close to the list price.

Yet another Swarovski that gets my highest recommendation: a great all-rounder with very few faults, just a wonderful view in a compact format.