The old Swarovski 15x56 SLCs were my
favourite hand-held astronomy binoculars. The latest model has been radically
re-engineered with the latest technology. In this review I find out if it’s
still a favourite.
Swarovski 15x56 SLC HD
Review
For some years, Swarovski’s older 15x56 SLCs were my
favourite hand-held astronomy binoculars. They were flawed in some ways – big
and heavy, with too little eye relief and too much false colour – but when it came
to finding and enjoying small DSOs it beat all comers.
Swarovski themselves admitted the old 15x56s were a
fifteen-years-outdated design, so they were due for an update to bring them in
line with the smaller SLC models. What the 56mm SLCs actually got, though, was
a significantly more radical re-design that differs from the smaller models and
moves them into the high end.
Let’s find out if Swarovski have really managed to improve on
the old 15x56 SLC without compromising its peerless optical quality.
At A Glance
|
Magnification |
15x |
|
Objective Size |
56mm |
|
Eye Relief |
16mm claimed, 14mm measured. |
|
Actual Field of View |
4.5 degrees |
|
Apparent field of view |
62 degrees |
|
Close focus |
3.9m |
|
Transmissivity |
93% |
|
Length |
192mm |
|
Weight |
1200g |
Data from Swarovski.
What’s in the Box?
This is the third pair of Swarovskis
that I’ve seen with this new box style. The box is flatter and a brighter
green. The Inner has an embossed Swarovski logo and a painting of a hawk (habicht) soaring over an alpine peak on the inside of the
lid.
I originally thought this was only for the European market,
but no it’s an official UK import. I guess it’s to compete with those classy
Zeiss boxes. Of course, you and I are much too sophisticated to be swayed by
such blatant marketing … or are we?
Design and Build
The older SLCs were a conventional large roof prism design
with a triplet objective using ‘normal’ (i.e. non-HD) glass. The new model has
several major technological improvements and design changes to fix the
shortcomings of the old model:
·
HD
lenses to curb chromatic aberration (false colour fringing)
·
Abbe-König
prisms (like Zeiss HTs, FLs and Dialyts) to improve
light throughput and brightness
·
Longer
eye relief to allow a full-field view with spectacles
·
A
significantly shorter, slimmer design
·
A
new focuser and dioptre mechanism, like other premium SWs
In other ways the new SLC 15x56 looks conventional, with a
stubby body and a conventional bridge, not an open one like the ELs’.
Body and Ergonomics
Though the body is apparently now magnesium alloy, it is
still quite heavy at 1200g: just 90g less than the aluminium-bodied pre-HD
model. That makes the SLC HDs lighter than the Zeiss Conquests and Nikon Monarchs,
but heavier than Zeiss’ 54mm HTs.
Appearance of the 56mm SLCs is now aligned with the 42mm SLC
models, with two-texture armour that is warm, comfortable and grippy but
doesn’t attract dust and marks like recent Zeiss armour. They have two-stage
sculpted thumb cut-outs on the back to make them easy to hold.
The 15x56 SLC HDs are significantly shorter than the previous
model and slimmer too: shorter than the Zeiss Conquest 15x56s, but about the
same length as the Zeiss 10x54 HTs and Nikon’s Monarch 16x56s.
Build quality is typical Swarovski – flawless and excellent,
identical to the more expensive ELs. Styling is plainer than the Zeiss 10x54
HTs’. The only criticism I could make of the body is the rather plasticky
hinge, which looks lower rent than the metal hinge on an EL. Overall, though,
this is a typical Swarovski – plain, but beautifully functional engineering.
These are the most ‘high-end’ big-eye
binoculars currently on the market.
Swarovski 15x56 SLC HD, Zeiss Conquest 15x56 HD and Nikon
Monarch 5 16x56 HD.
Focuser
The focuser is oily-smooth and precise with absolutely no
play or stickiness, but a bit heavier than the Els’. The feel of the focuser is
the same as the 10x56 model, but seems slower at almost two turns to go from
closest focus to infinity. I guess that this model is expected to be used on
static targets, not birds on the wing. Accuracy and smoothness are faultless,
but I’m not sure I don’t prefer the lighter, faster feel of a Zeiss HT or
Conquest.
The dioptre adjustment is the best around and can easily be
done one-handed: snick out the focuser wheel for a click-stop mechanism with an
accurate scale.
New SLC focuser is much like the ELs’: Pull to adjust the
dioptre.
Optics - Prisms
Like the other 56mm SLC HDs and Zeiss Victory HT and larger
Conquest models, these have Abbe-König prisms, different from conventional
Schmidt-Pechan roof prisms. Different how and why?
Well, Abbe-König prisms are longer and thinner, allowing a more tapered body
design. More significantly, Abbe-König prisms don’t require mirrors (no SWAROBRIGHTTM dielectric
coatings needed) – they bend the light by total internal reflection and so
transmit slightly more light as the result. Swarovski
claim 93% transmittance for these, compared to about ~90% for the very best
conventional roof designs like their EL models.
Abbe-König prisms do make for a
brighter binocular; all the brightest roof-prism binoculars I’ve tested have
them.
Optics - Objectives
Swarovski’s premium range, the ELs, contain 24 optical
elements. Remarkably you might think, these 15x56 SLC HDs have even more - 26
optical elements (i.e. 13 per side). So where does all
that glass go, then? One possible answer is the objectives, in order to deliver
a short body and freedom from aberrations. Another possibility is that these in
fact have field-flatteners (see the discussion of field flatness below).
Swarovski don’t publish details of the lens design, but given
those 26 optical elements and (as we will see) given the outstanding false
colour correction, these probably contain two HD elements made of
high-fluoride glass, as the Zeiss HTs (and Kowa 10.5x44s) do.
The SLC HD range don’t boast premium SWAROVISIONTM technology like the ELs’ and their
coatings have a pink reflection where the ELs’ is greenish. But to me, the
coatings on the SLCs look more transparent, less reflective.
The barrels incorporate knife-edge baffles to control stray
light and internal build quality appears good and rugged.
No SWAROVISIONTM
tech’ for the SLCs (right), but their coatings actually look more
transparent than the Els’.
Optics - Eyepieces
These SLC HDs clearly have a complex eyepiece design. The eye
lenses are about one millimetre smaller than the ones on the 10x56 model, but
much larger than the old 15x56s’. Compared to the Els, the eye lenses are much
smaller and a very different design, though (see below).
These eyepieces give improved eye relief and a larger field
(4.5° vs 4.1° for the old model). That’s a wide
field, but not as wide as the Zeiss Conquest 15x56s’, which come close to the
field width of some 10x binoculars, albeit with more off-axis aberrations than
these Swarovskis.
The exit pupils
look properly round and un-vignetted; internal reflections are well suppressed.
Eye relief is claimed to be 16mm, but I measured 14mm from the rim of the eye cup. So
these have a lot less eye relief than the 10x56 model and the whole field isn’t
quite visible with my glasses on. No compact high-power binoculars have
generous eye relief and these SLC HDs still have more than the older model and
as much as a pair of 56mm Zeiss Conquests, even though those claim to have
18mm.
Kidney-bean blackouts as you move your eye around
(technically known as spherical aberration of the exit pupil) are non-existent,
which is good news for comfort.
Multiple click-stop eye-cups are provided and they work well,
but are not oily smooth and damped like the ELs’. The cups are slim – good for
people with close-set eyes.
15x56 SLC HDs have smaller eye lenses than the 10x50 Els.
Swarovski’s usual
multi-adjustable and very solid eye cups aren’t quite as oily-smooth as the
Els’.
These are the Zeiss 15x56 Conquests’ eye cups for comparison
– poorer quality and thicker, ruining their potentially better eye relief.
Accessories
The UK model now gets a slimmer padded field case, plus the
usual ‘lift’ strap and lens cloth. Objective caps are the band-on type and work
well enough. The eyepiece cap is hinged and fits very snugly over the cups.
Swarovski make a very high quality tripod adapter (see discussion below), but it’s
a costly accessory (Zeiss give you one for free with the 15x56 Conquests).
Other possibilities include an iPhone adapter for taking snaps through the binos.
Tripod Adapter
To fit the adapter, you first need to pop the cover off the
front of the hinge and screw-on a lug on the front. This is tricky to do – you
have to set the hinge to its widest and then prise the cap off, revealing the
thread for the adapter lug. The cover is plastic and you’re almost bound to
have to use a screwdriver which risks damaging it (no UK coin is really small enough, I used an old Dutch coin here). Then you screw on
the lug with the provided Allen key and tighten down a set screw to stop it
shifting.
Once fitted, the lug just slides into the adapter and a flick
of the lever locks it in place. It’s an elegant and efficient solution.
Fitting the tripod adapter lug is a fiddly process.
Swarovski’s tripod adapter is a classy thing, ‘Made in
Austria’. But it’s NOT included for free.
Once the lug is fitted, mounting the big Swaros
on a tripod is quick and foolproof.
In Use – Daytime
Ergonomics and Handling
The sculpted body falls naturally to hand. These are
comfortable to hold. I like Swarovski’s armour – it’s grippy, warm,
hypoallergenic and doesn’t smell of rubber; it doesn’t attract dust either.
This new version feels much smaller and lighter than the old
one, but there is still space to put your hands around the objectives for
steadying them when you don’t need quick access to the focuser.
Slightly tight eye relief is really the only downside to
these binoculars. I can’t quite see the whole field with my chunky retro-framed
specs and you might not be able to either. The eye relief is still better than
the old model’s, though.
These look big hanging around my neck, but I wouldn’t feel
quite such an idiot walking up the local fell with them on a sunny Sunday as I
would have with the old model.
Despite the
cutouts, holding around the barrels is still the most natural way to damp those
high-power shakes.
The new SLCs
don’t look as enormous hanging around my neck as the old model, but they’re
still a big binocular.
The View
These don’t have the immediate ‘wow’ factor of the 10x56
model’s view, but that’s simply because the real width and depth of field are tight
due to the high power. Once you’ve got over that, the view is really excellent
– bright, sharp and full of detail, so much better than the old model’s.
Again, I need to point out that daytime brightness isn’t due
to the big lenses. Your pupil contracts during the day and so stops the optics
down to perhaps a 15x30 or 15x20. Under these conditions
brightness is down to the transmissivity of the coatings and prisms. The Abbe-
König prisms make a noticeable difference here compared to the older SLCs or other
big-eye binos that use roof prisms, like the big
Nikon Monarchs.
Optical quality is supreme – both barrels have an absolute
focus snap that really demands the precise and accurate focuser these have. The
focus point is exactly the same focusing in and out, something a lot of lesser
high-power binoculars fail at (the Nikon Monarch 16x56s for example).
Both the Zeiss Conquests and the SLC HDs have similar
coatings with a pinkish tone. No surprise then that these give the same vivid,
but neutral, rendition of colours as the Zeiss.
Put these on a tripod and the daytime view is gorgeous –
wide, vivid and full of detail; few scopes manage this kind of optical quality.
Overall, the daytime view is among
the very best for a high-power design.
Flat field?
These have almost the perfectly flat field of a Swarovski EL.
Field curvature, astigmatism and coma remain negligible and even distortion
doesn’t begin to creep in until the last 10% or so. In the daytime that means
you could ID a bird at the field stop.
Interestingly, the 15x56 SLC HDs on test here have a flatter
field than the 10x56 model.
The view is flat enough to give that ‘rolling ball’ effect
when panning.
Below are two photos taken with an iPhone adapter. The first
is through the 10x50 ELs. The second was taken through the 15x56 SLC HDs. Note
that field flatness is very similar: the 15x56 is just a little less sharp at
the very edge.
Swarovski 10x50 EL.
Swarovski 15x56 SLC HD.
Chromatic Aberration
Chromatic aberration is extremely well controlled, really
remarkably so for such a high-power, big-objective design.
Tree branches and birds seen against a bright sunny sky are
completely free from false colour in focus in the centre of the field. Even
when focussing through or panning there is just a trace. The local roof peaks
and chimney pots that usually show coloured fringes just don’t with these. The
kaleidoscope of false colour fringing you sometimes get when panning through
silhouetted branches is completely absent.
Just a little more false colour
creeps in towards the edges, in perhaps the last 10-15%. But these show
significantly less false colour than the competitor Zeiss Conquest 15x56s,
especially off-axis.
The CA performance of the 15x56 SLC
HDs is the best I have seen in a high-power model. They are essentially
false-colour free in normal use. I really love this feature: it is possible to
enjoy birds in high branches with plumage the only colour you see.
In Use – Dusk
These have a very high ‘twilight rating’ due to the large
aperture and high magnification, but I personally reckon the 10x56 model is
better in twilight. That said, these do penetrate dusk shadows very well if
compared to say a 10x42 and have a real light-intensifying effect in full
night. I imagine these would be ideal for owling or night hunting.
In Use – The Night Sky
The field is nearly perfectly corrected. A trace of off-axis
curvature is noticeable beyond 90% field width, but it is modest. Stars remain
star-like all the way to the field stop. There is minimal astigmatism and coma
– most of the residual off-axis blur can be focused out. This is unlike a Zeiss
Conquest, for example, which has some residual aberrations that can’t be
focussed away.
Stars in the broad central sweet-spot are particularly small
and tight, giving them extra intensity and brighter colours, helped by the
absence of false colour, even on bright O-A stars like Rigel or Vega.
The superb optics and high power suppress Moonlight and
sky-glow much better than most binoculars. Aldebaran still shone burningly
bright and intensely coloured right by a full Moon.
I was unable to get any ghosting, even from a full Moon.
Similarly, veiling flare around a full Moon or streetlight was generally well
suppressed. Looking at a bright security light produced no ghosts or spikes of
any kind – an outstanding result that confirms the care taken with coatings and
baffles.
I am used to the high power and generally don’t find it a
problem. I rest on my car when I can to reduce shakes, but generally these just
show you more.
The Moon
The Moon nearing full is painfully bright, but still almost
free from false colour through the SLC HDs, just hard greys and whites.
Resolution is outstanding and I can see a lot of detail, even hand-held: the
shadow in Kepler, the Messier twins, the peaks in Copernicus, Schiller near the
terminator, the Tenerife Mountains.
Mount the 15x56 SLCs up on a tripod and the Moon is
stunningly detailed, with all the major atlas features and craters easy to
explore, all picked out with perfect sharpness and contrast, like a fine small apochromatic
refractor but in stereo (the Moon scudding through icy clouds is mesmerizingly
lovely in 3D).
Venus
Venus flared just too much to discern a phase, but the level
of flare was lower than most. Venus generated virtually no false colour,
despite dazzling brightness.
Jupiter
Jupiter showed no smearing or spikes, just a perfect disk
with a hint of dark markings (the central belts). The Galilean moons were
especially easy to pick out, even near the planet.
Deep Sky
The Great Nebula in Orion still showed lots of nebulosity
even in bright Moonlight. Similarly, I was able to find the Dumbbell Nebula in
a sky flooded by the light of the full Moon. Under a dark sky, M42 reveals much
more extended nebulosity than through 10x42s.
In general, these repeat the performance of the old model on
DSOs – enabling you to pick out and find shape in planetary nebulae and
globular clusters you would struggle to find at all with lesser binoculars.
These aren’t just about planetary nebulae, though. The
improved real field is plenty wide enough to encompass almost any cluster,
helped by the fact that almost the whole field is usable. Clusters just look
more populous and interesting. The Pinwheel and Starfish in Auriga showing
their shapes better than through smaller bino’s and with
direct vision, where most binoculars demand averted vision to resolve them. In
a dark sky, Cassiopeia revealed numerous faint clusters.
The Pleiades are dazzling diamonds, with hints of the
nebulosity around them.
Bode’s twin galaxies look much more interesting
– clearly different shapes – than through most binoculars. There is ample field
to fit in the whole of M31 as well and again galaxies show more hint of
structure than you get with most bino’s under dark
skies. Finding M33 is easy.
Performance is currently the best
available for hand-held astronomy, with the HD optics adding a little extra
clarity, contrast and true colour to the already excellent night sky abilities
of the pre-HD SLC.
Testing the Swarovski 15x56 SLC HDs in their element – on the
night sky.
Swarovski 15x56 SLC HD
vs Swarovski 15x56 SLC Neu
Here is a summary of the improvements Swarovski have made to
the latest SLC 15x56, compared to the (confusingly named) older, pre-HD ‘Neu’
version.
·
The
HD lenses in the latest version make a big difference by virtually eliminating
false colour fringing – during the day, but at night too on the Moon, planets
and bright O-A stars
·
The
latest version has optics every bit as sharp as the old
·
The
field in the new version is both wider and flatter
·
The
new version is very noticeably brighter in the daytime, due to those Abbe-König
prisms and the latest coatings
·
Overall, the daytime view through the
HD model is much more pleasing than the old
·
Eye
relief is still a bit tight, but better than the old version and quite usable
with glasses (even my chunky specs vignette just the edge of the field)
·
The
new version is considerably more compact and a bit lighter
·
The
new focuser is excellent – a bit smoother than the old model’s
All these improvements mean the latest Swarovski SLC 15x56 HDs are less
of a niche binocular than the old model, whilst retaining the outstanding
high-power performance.
Swarovski 15x56 SLC HD
vs Zeiss Conquest 15x56 HD
These are very similar, competing binoculars and a comparison
is in order. A summary of their relative merits follows.
·
The
SLC HDs are shorter and 90g lighter
·
The
SLC HDs have a narrower (63 vs 69 degrees apparent) but even flatter field
·
The
SLC HDs have a couple more millimetres of eye relief –not in the brochure, but
in the real world
·
The
SLC HDs show significantly less chromatic aberration centre field and much less
towards the edge
·
The
view through the Zeiss is otherwise as bright, sharp and detailed as the Swarovskis’. Optical fabrication quality is every bit as
good
·
The
Zeiss focuser is lighter and faster but less oily smooth
·
Some
aspects of the Swarovskis – the eye cups and the
armour – show higher build quality
·
Zeiss
throw in a top-quality tripod adapter
The Swarovski SLCs are unquestionably
the better binocular, but they are also about 30-40% more expensive at the time
of writing. I am a perfectionist and would buy the SLCs, but the Conquests are arguably
better value.
Summary
These new 15x56 SLCs don’t have the quite user-friendly
daytime view of their 10x56 sibling – they’re just too high power for that. But these binoculars are still spectacularly
good for such a high-power design, the very best I’ve tested and much more usable
than most.
Not only are the new 15x56 SLC HDs shorter and lighter than
the old model, they have a wider field, almost no false colour and a bit more
eye relief too. Optical quality is supreme, beyond criticism. All aberrations
are tightly controlled across the field. The apparent field is wide at over
sixty degrees, yet field flatness is even better than the 10x56 model and approaches
other explicitly flat-field designs. In-field ghosting and flare are
non-existent. The focuser is a little slow, but silky smooth and accurate.
So the result is a great daytime view –
sharp and bright and enjoyable, free of false colour and very detailed. Overall
the daytime view is much better than
the older 15x56 SLCs, due to the higher transmittance and HD optics which
deliver a much brighter, more pleasing image.
But like their predecessors, it’s at
night that these really come into their own. Night sky performance is outstanding. In this latest
version, the 15x56 SLCs give a wider, flatter view with less false colour on
the Moon, planets and bright stars and better eye relief for specs wearers. Like
the old model their ability to pull in deep sky detail is unrivalled in
hand-held binoculars.
If you can stand the high power (try before you buy!) these
are the best hand-held astronomy binoculars on the market and are optically
among the finest binoculars I have ever tested (as of early 2017). They get my
highest recommendation.
Buy Swarovski 15x56 SLC HD from Wex here:
