ZEISS SFL 10x30 binocular

Less than seven months after ZEISS introduced two 40 mm lightweight binoculars to the market, 17 January 2023 saw the launch of two more models in the SFL range. With the emphasis firmly on weight reduction and a compact format, these new 30 mm binoculars offer the user a choice between 8x and 10x magnification, without compromising overall quality.

When it comes to owning binoculars, I have always been a fan of the higher of these magnifications, preferring the extra reach they provide, so I was pleased to be offered the chance to assess the performance of the greater of the two magnification values. 

Performance, of course, is not simply limited to optical quality alone. Design, functionality and ergonomics all play important roles in the ‘comfort factor’ associated with the overall use of any optical equipment and the 30 mm SFL sets out to maximise this.

Simply put, SFL is an abbreviation of 'Smart Focus Lightweight'. The 2 mm reduction in the diameter of the objectives – down from the established, popular Victory SF 32 – has made possible the use of thinner, more closely spaced glass elements and a smaller body size. A side-by-side comparison of the two reveals reductions in length and weight by 20% and 22% respectively, while a direct comparison against the SFL 40 uncovers further equivalent reductions amounting to 17% and 28%. Indeed, weighing in at a mere 460 g renders the SFL 30 the lightest model on the market when compared to 32 mm binoculars from established top-tier brands.

In terms of its low weight, then, the bottom line is it's very easy to forget you are wearing this binocular while in the field – and that’s a big plus.
The SFL's structural design also has much to commend it. I found it to be perfectly balanced and, with the strap lugs set well back from the deeply milled focus wheel, it allows the fingers operating the latter to be kept perfectly straight, making this binocular very comfortable, both to hold and to operate. 

Focusing is rapid and precise and, with no extraneous play in the wheel, approximately 1.3 clockwise turns takes the image from close focus to infinity. The manufacturer's figure of 1.5 m for the latter is absolutely spot on and a mere quarter of a turn moves the focused image on from 10 m to approximately 500 m.

Turning smoothly, the single-eye focus (dioptre) is positioned below the eyecup on the right ocular although, beyond a simple +/- indication combined with a spot-marker, there is no reference scale and no ability to lock the setting. Nevertheless, I discovered it does not move during field use and appears to maintain its set position at all times.

Overlaid with soft rubber, the twist-out eyecups deliver comfortable viewing, positively and firmly click-locking in three optional positions above the fully retracted setting. To my eyes, the whole field of view was visible in all positions, except on the furthest extended setting, in which there was a minor shortfall. Interestingly, the field of view in this binocular pans out at a respectable 120 m at 1,000 m – beating the 10x40 SFL by 5 m.

The image itself is very pleasing and surprisingly bright for a small-objective binocular with a magnification of 10x, even in low light conditions. My locally wintering Yellow-browed Warbler in Northamptonshire still stood out brightly in the fast-fading light of late afternoon, just prior to its going to roost at dusk. Crisp, clear and accurate colour rendition and contrast are evident across a range of habitats when viewing birds generally and the field of view offers edge-to-edge sharpness, with negligible curvature or distortion. 

There is some chromatic aberration visible, minimal at the centre of the image and, to my eyes, it appeared marginally more noticeable than that in the larger 10x40 SFL model, reviewed last year (Birdwatch 360: 48-49). It did not, however, detract from the viewing experience.

With its magnesium body shrouded simply with soft, non-slip rubber armour, the SFL 10x30 is designed for compactness and ergonomic performance as well as delivering high optical quality. In these respects, it easily ticks the boxes but there is a danger that, in so doing, it may not suit users with particularly large hands! This is, perhaps, a minor detail.

In terms of accessories, this binocular comes with the same smart, innovative and unique objective lens covers used in the larger model, a comfortably padded lanyard and an articulated rainguard. For protection, transport and storage a soft, padded carry case comprising 100% recycled fabric made from upcycled PET bottles completes the package.

Priced at a reasonable £1,350, the SFL 10x30 is undoubtedly a lightweight binocular which clearly punches above its weight.

 

Further info

• Price: £1,350
• Size: 120 x 107 mm
• Weight: 460 g
• Field of view: 120 m at 1,000 m
• Light transmission: 90%
• Close focus: 1.5 m
• Gas-filled: yes
• Waterproof: yes
• Guarantee: 10 years

 

Verdict

+ Incredibly lightweight
+ Crisp and bright image
- May be tricky to use for those with large hands