The 10x40 Zeiss SFL impressed me, but arguably their lightweight design makes even more sense in a super compact 30mm that finally offers a true replacement for the late lamented Victory FL.
Zeiss 10x30 SFL Review
Compare a Ferrari 308 GTB from the 1980s parked by a modern 296 and the first thing you notice is that new car is just so much bigger. Premium binoculars have been a bit like that in recent years.
Zeiss’ premium 32mm birding binoculars, the SFs, are the very best. But there’s no escaping that they’re large – significantly larger than the Victory FLs they replaced as top-of-the-range. We’d all love the optical performance of the SFs in a package as small and light as the FLs, but is such a thing even possible? Zeiss would like you to believe their new 30mm SFLs aren’t far off, but as usual read on to find out…
At A Glance
18mm claimed, 15-16mm measured from the rim of the eyecups
Actual Field of View
Apparent field of view
465g measured w/o caps.
Data from Me/Zeiss.
SFL: designed for an easy carry on long days in the hills.
What’s in the Box?
This pair didn’t come boxed, so no unboxing pics, but the box is a typical Zeiss logoed white carton.
Design and Build
Zeiss describe the SFL as ‘part of the SF family’, but ‘optimised to be as compact and lightweight as possible’. So these are a premium binocular, albeit lighter, more conventional and cheaper than the current top-of-the-range SFs.
Indeed their finish and look is like the SFs’, but very different from the older premium Victory FL model that is nonetheless closer to the SFLs in size and design.
Made in Japan
I’ve seen some slightly shoddy Zeiss bino’s in the past, but recent SFs have been great. Strangely, though, these SFLs seem every bit as good, both optically and mechanically, despite being (a lot) cheaper. What’s going on?
On the bridge of the SFLs it says ‘Designed by Zeiss’ but hidden away under the hinge is ‘Made in Japan’ like the larger SFLs and the folding Pocket models. Does this matter? Possibly.
Look, I love Japanese-made gear. Most of my astro’ scopes are Japanese and some of my hi-fi too. But binoculars take much heavier wear than scopes or amplifiers.
If you drop (or just wear out) a pair of German-made Zeiss, you can send them off to be completely re-manufactured for a modest sum. Unfortunately, my experience of doing this for optics (and indeed hi-fi) made outside Europe has been much less reassuring.
I honestly don’t know if long-term support for Zeiss’ Japanese products like the SFLs will be as good as for European models, but when a pair of Pockets went out of collimation Zeiss just sent me a new pair.
The SFLs compared with the 32mm Victory FLs and tiny Swarovski Curio 7x21s.
The overall impression is of a handsome but tiny binocular. Let’s look in more detail.
The SFLs have a conventional bridge and body - more like the cheaper Conquest model, not the open design of the SFs. Unlike the cheaper Conquests, though, the SFLs’ body is made of magnesium to help keep the weight down. The SFLs are waterproof to 400 millibar and nitrogen purged as usual.
The 10x30 SFLs are remarkably light at just 465g on my scales: ~22% lighter than the 10x32 SFs as claimed. They are 20% shorter than the SFs too at just 120mm long. They’re even 20% lighter than the old 10x32 Victory FLs; but though they’re much less bulky, length is roughly the same, as you can see above.
The SFLs’ finish is like the SFs’. The armour is well fitted, doesn’t smell rubbery, is grippy and isn’t a magnet for dust and prints. All good then? Not quite. The armour is thin, and the bridge and lugs are anodised metal. The current trend of exposed metal in the bridge looks classy, but when it scuffs and scratches there’s no repair possible.
Overall, these probably won’t be as rugged as the old Victory FLs, which have thicker full armour and more deeply recessed objectives too.
The SFLs share the SF for ‘Smart Focus’ brand and have a big rubberised wheel like the SFs. It works via the usual focusing lens behind the objectives, though, not the moving-objective system found on the 10x32 SFs.
The focuser feels smooth and precise, but just as for the larger SFLs it’s not as light and fluid as the SFs’.
Close focus measured at a super-close 1.2m. This is a great feature for observers of insects, but note that I struggled to merge the image much below about 2m.
It’s a fast focuser, with infinity arriving after just over a turn. Thereafter there’s lots of extra travel to cope with various prescriptions too.
The dioptre adjustment is via the usual ring behind the right eyepiece. The action is well weighted, but slightly vague. There’s a mark for neutral, but I’d prefer a click-stop. The bridge-mounted wheel on the SFs and old Victory FLs makes fine adjustment easier, but is a premium feature that doubtless adds to cost and maybe weight too.
Optics - Prisms
These have a standard Schmidt-Pechan (a.k.a. Roof) prism design, that need both mirror and phase coatings. Transmission is 90%, a couple of percent down on the SFs but good by general roof-prism standards and equal to the old FLs (the 32mm FLs had Schmidt-Pechan prisms too, unlike the larger models with the their higher-transmission Abbe-Königs).
Optics - Objectives
A laser suggests the objectives are a triplet with at least one crown of ED glass – special extra-dispersion glass high in fluorides to quell false colour fringing. Like the 10x40 SFLs, the triplet comprises a cemented doublet in front and a single air spaced convex element behind.
Zeiss reckon that the smaller objective diameter (30mm vs 32mm) helps keep the weight down by allowing thinner lens elements. How much less light do those 30mm lenses collect? Roughly 12% less by my slide rule.
To control stray light, each barrel contains a single knife-edge baffle behind the objective. The focuser carriage has multiple ridge-baffles and a single knife-edge baffle at the rear too, but no special black paint or other flocking. There are fine baffles in the lens ring.
Zeiss claim premium T* Coatings for SFLs, but these are more like generic coatings, with reflections in tobacco and green, not the distinctive dark pink/purple found on the SFs and old Victory FLs. The coatings are very transmissive, though a bright light finds a single internal surface that appears uncoated. The coatings have LotuTecTM water-repellent technology.
Coatings get the T* label, but are very different from the old FLs’ here (and the new SFs’ too).
Both ridge and knife-edge baffles for maximum stray light protection.
Optics – Eyepieces
The eye lenses are large at 23mm diameter and flat, much like the SFs’ but larger than the old FLs’.
Eye relief is sufficient for most people’s spectacles, even though I measured a modest 15-16mm from the rim of the cups. That’s slightly more than the old Victory FLs’, but notably less than the SFs’ and less than the 18mm Zeiss claim.
Suppression of blackouts as you move your eyes around (caused by spherical aberration of the exit pupil) is a little better than the 10x32 SFs (the one weak point of that model for me), but a little worse than the best.
Apparent field of view is 65°. That translates to a 7° true field (120m/1000m): less than the 7.6° (130m/1000m) for the 10x32 SFs, but wider slightly wider than the Conquests’ and good by general standards.
The rubber eye cups twist out to three extra positions. The action is positive and firm with no squish or problems re-seating them.
The objective caps are fitted to look as if they’re integral to the armour, but actually they push on and are replaceable. They work well, if occasionally fiddly to push in so they don’t pop out again. The eyepiece cap is the standard soft rubber.
The strap is completely standard Zeiss too, as is the semi-rigid Cordura case. Both are the same as the 10x32 SFs I reviewed and entirely functional, if not as fancy as Swarovski’s typical premium offerings.
In Use – Daytime
Ergonomics and Handling
There is no ErgoBalanceTM rearwards weight bias (SFs) or specially contoured body (Swarovski NL Pures) here, but the SFLs are exceptionally small and light to carry. This matters for me: I wore them on some all-day rambles in the Lakeland hills and really appreciated it, even when compared to the Victory FLs. With these there’s just less reason to drop to a folding pair on long walks and treks.
The large focuser comes easily to a gloved finger. Focus action is not as liquid-light and twirly as the SFs’, but it is smooth, very fast and precise, with no play or backlash and no variation in focus point when switching direction. This matters because perfect focus is an unusually exact point, same as for the larger model.
Just as Zeiss advertise, eyepiece comfort is excellent, again like the 10x40 model. Eye relief is a little tighter than the 10x40s as expected, but still enough to see the whole field with my spec’s on and just a little better than the old FLs. Blackouts are well controlled, but more noticeable than the very best, something you can see in the field of view snap.
For an armoured binocular these are unobtrusive and look classy to wear if that matters to you.
Like the larger SFL models, these give a beautiful view: bright, wide, detail-filled and vibrant, with no obvious aberrations. The view is also notably easy and relaxed for 10x bino’s, especially for such a small aperture which can often feel somehow ‘tight’.
Considering the different hue of their coatings, the colour balance is surprisingly similar to the old Victory FLs, but perhaps a little less vivid in blues and greens to my eyes.
The focus snap is a fine point, with just the slightest nudge on that precise wheel to get it perfect. I’ve seen this before with the larger SFLs and with Kowa’s XD models; it usually means superb optical quality.
From the top of the fell, I watched a stationary Hawk, riding the updraft and hunting: a false-colour free, HD view in partial silhouette.
Sweeping the crowds, rides and stalls at Cartmel Races funfair, a mile distant and down in the valley, the clarity and resolution were amazing: even my wife, who is no bino-fan, commented on it without being asked. I started looking for people I recognised, something only possible with the highest resolution bino’s at that distance.
The SFLs’ view is not be quite as super-wide as the SFs’, but it’s still a truly great view.
Field is well corrected off-axis, with minor curvature causing some blur at the edge and some distortion too.
The field seems well corrected (and completely usable) to the field stop. Inspection of my meter rule reveals that the cm markings get progressively blurry in the outer third, but are still (just about) readable at the edge. Most of this blurring can be focused away, though: it’s field curvature with just a touch of astigmatism.
There’s some distortion for comfortable panning, visible in the FOV snap above, but you mostly only notice it panning through branches.
In keeping with the UHD tag, centre field false colour is well controlled and the trace that remains probably comes from the eyepieces (there’s very little focusing through).
Typically for Zeiss binoculars, though, false colour fringing does worsen towards the edge of the field and is noticeable when panning through silhouetted branches.
Stray Light and Ghosting
Viewing a bright LED streetlamp produced two bright, long spikes from prism corners in the right barrel only. I’d regard this as a minor fault restricted to this pair, though it doesn’t manifest otherwise.
Coincidentally, I recently bought a pair of Swarovski 12x50 ELs which suffered the same problem and I sent them back; the replacements were fine. As always, buy from a dealer with no hassle returns and check them as soon as they arrive – viewing the LED flashlight on your phone across a room is a great test for flare and spiking issues.
Working below a setting Sun or a bright dusk sky, there was no noticeable flare, an excellent result.
In Use – Dusk
Viewing bay waders in deep dusk, twilight performance was creditable. I was still able to distinguish ducks, egrets, geese and gulls way out in the shallow waters. But these don’t have the quite the dusk penetration of the brightest 10x32s.
In Use – Observing the Night Sky
The smallest aperture of any real use for astronomy is 30mm, but with good transmittance, a flat field and superb optical quality these work quite well.
Star images are tight and pinpoint until the last 15-20%, when field curvature distorts them. There is only a little astigmatism at the very edge. The field is wide enough that the whole trapezoidal asterism that’s part of the constellation of Lyra easily fits with minimal distortion.
The SFLs gave a great view of a first quarter Moon – sharp and with no false colour and good contrast against a dusk sky, with the classic grouping of Theophilus, Cyrillus and Catherina on the terminator.
Brilliant Venus was the only planet around, showed no false colour or significant spikes, but more flare than the best (likely due to the minor fault on this pair noted above) and no chance of identifying its phase.
Unfortunately, Zeiss released these loaners at the end of May, a time of year which officially has no astronomical darkness up here. Consequently, I wasn’t able to fully test them on deep sky. However, with Cygnus lower in the sky than I’m used to during the astro’ season here, I did get a nice split of Albireo and found some Milky Way clusters above Deneb.
Zeiss 10x30 SFL vs Zeiss 10x32 Victory FL
I’ve compared the 10x30 SFLs to the full-fat SFs throughout this review, but the other interesting comparison is with the older top-of-the-range 10x32 Victory FLs for which the new SFLs are actually a closer replacement. Overall these are (perhaps not surprisingly) pretty similar, but let’s break that down:
· Size is very similar, as you can see
· The Victory FLs are bulkier and ~100g heavier
· Optical quality is similar
· The SFLs are perhaps slightly brighter by day, despite the FLs boasting the same premium coatings as the SFs
· The Victory FLs’ extra 2mm aperture might be noticeable in very low light
· The SFLs’ field is a little better corrected off-axis
· The SFLs have slightly more eye relief
· The Victory FLs’ focuser is more fluid and better positioned for me
· The Victory FLs are better armoured and feel more rugged with no exposed metal
· The Victory FLs’ objectives are more deeply recessed
· The SFLs are a bit cheaper than the last list price of the Victory FLs (and that after recent inflation)
· Perhaps I don’t need to point it out, but the Victory FLs were made in Germany, the SFLs in Japan
The SFLs are as good or perhaps slightly better optically, but the Victory FLs have the better focuser and will prove more rugged with their full, thick armour and deeply recessed objectives. If I was going to subject them to really intense field use I’d buy a good used pair of Victory FLs and maybe get them serviced, otherwise the SFLs are a great current alternative.
The 10x30 SFLs are close to perfect in most ways. They are indeed extremely small and light for a 30mm binocular. Their view is excellent: wide, bright, detailed and with lower off-axis aberrations than Zeiss of yore. External build quality is excellent too and optical quality outstanding. Eyepiece comfort is very good for a small binocular. The focuser is fast and accurate and they focus close for insects.
Any negatives then? They don’t <quite> have the super-wide and sparkling-bright view of the SFs (or indeed SW’s NL Pures), or its ultra-fluid focuser. The thin armour and fashionable exposed metal mean they won’t be as rugged as the old Victory FLs. I’m a little concerned about long-term repairability given the Japanese manufacture.
Still, they are attractively priced for a premium model and a great replacement for the old Victory FLs if you need an ultra-light yet ‘full-sized’ bino’s for long field days, treks or travel.
The 10x30 SFLs are a true replacement for the old Victory FLs at last: they’re super light and have a great view, ideal for trekking or travel or just long days in the field. Highly recommended.
Buy Zeiss 10x30 SFL from Wex here: