Zeiss SFL 8×40 binoculars review

by Mike Weedon |

These binoculars from Zeiss somehow squeeze just about all the excellence of the well-established 8x42 SF binoculars into a slightly smaller objective lens diameter pair, which is considerably smaller, lighter and some £800 less expensive. To me, it seems like a minor miracle!

Verdict- these are brilliant binoculars offering the excellent performance of their larger siblings in a much smaller, more lightweight pair. For binoculars of this quality, they are very good value. Definitely worth a tryout, they are hard not to love, and that's why they're on our Best Binoculars for Birdwatching round-up.

Eye relief: 18mm
Field of view: 140m @ 1,000m
Close Focus: 1.5m
Weight: 640g
Length x width x depth: 140mm x 118mm x 52 mm (fully opened)Warranty: 10 yearsSupplied with: Padded case, neoprene strap, rainguard and objective eyecups

Ratings (out of 5)
Optics 5
Handling 4½
Price 5
Overall 5

Zeiss SFL 8x40 binoculars review

I have been using Zeiss binoculars since the launch of the 8x42 FL (in fact I had a 7x42 FL pair) in the Noughties.

My tried and well-tested pair were replaced with Zeiss 8x42 SFs a few years ago, which are the pair I use every day. The new 8x40 SFLs (the L stands for lightweight, to go with the smart focus of the SF) take the SF design and tweak it, losing the hinge near the objective end, but retaining the comfortable position of the (1.5 finger wide) rubberized focus wheel (which performs very well, smoothly and precisely, with just less than one and a half turns from close to infinity).

The dioptre adjustment has ‘moved’ from being near the focus wheel to being by the right eyepiece. It is a rubberized affair without click stops, which stays in place well. And the eyecups (which twist and click-stop to four positions to alter eye relief) are more rounded and more comfortable than the ones on my 8x42 SF pair.

My one gripe about the SF is that these eyecups can twist out of position when I don’t want them to. The SFLs seem to have a better lock, so this didn’t happen while I was using the 8x40s.

Comfortable, well balanced and relatively lightweight ©Mike Weedon

The focus wheel is smooth and precise (though in the pair I tested not quite as buttery smooth as my well used SF’s focus wheel).

High performance

Remarkably, though the objective diameter is only 2mm smaller, the SFLs are considerably smaller (e.g., compare the length of 144mm with the 173mm of the SFs) and lighter (640g versus 790g). This means you have a pair of 8x40 binoculars which look and feel more like 8x32s but have a performance akin to 8x42s (incidentally the 8x32 SFs are 152mm long and weigh 600g).

And this, for me, is the magic of these new binoculars. I compared them side by side with my 8x42 SFs over a range of conditions and times of day, in April and May; and the difference between the pairs is minimal. Indeed, perhaps because I am so used to Zeiss binoculars, I needed no time to ‘adjust’ to using the 8x40 SFLs. Both pairs delivered wonderful, natural, ‘walk-in’ images we all expect these days from the best binoculars. These are the sort
of images which are sharp and realistic across the full width and up with the best available.

Offering images that are punchier and more exciting than the SFs... ©Mike Weedon

In some ways, I preferred the image of the SFLs which could appear punchier and more ‘exciting’, though that may sound strange (considering the slight size difference and considerable price difference).

I watched a close male Whinchat from my car a few days ago: it was beautiful through both pairs, but seemed to deliver an extra level of excitement though the 8x40 SFL.

I found a very subtle difference in colour, with the SFs appearing very slightly yellower and very slightly flatter (in colour terms) than the slightly bluer SFLs.

Both pairs require some pretty extreme lighting (or very odd angle of viewing) to force them to show any colour fringing, which is minimal, anyhow, but perhaps (and you really do have to look hard for it) slightly easier to detect in the new binoculars.

The focus wheel performs smoothly and precisely (hand model: Jo Weedon) ©Mike Weedon

Hard to fault

The official field of view at 1,000m is very similar (140m for the 8x40 SFL versus 148m for the 8x42 SF) and side by side, they also seemed very similar, to my eyes. Similarly, the close focus of about 1.5m was the same for both (and better than adequate, even for those of us who love to look at insects up close and personal).

The SFLs come with the usual and expected range of accessories, including the very decent Zeiss strap, rain guard and objective lens covers (which I tend not to use) and a decent though basic padded case.

In summary, the 8x40 SFLs deliver a superb performance in a very comfortable, well-balanced and relatively lightweight package. These are not inexpensive binoculars, of course, but it seems amazing for me that these binoculars can retail at £800 less than their larger siblings. To this birdwatcher, they seem a bargain!

Just so you know, whilst we may receive a commission or other compensation from the links on this website, we never allow this to influence product selections - read why you should trust us