Field Test: Zeiss SFL 8x40 Binocular

The author tests the new Zeiss SFL 8x40 binocular during South Dakota’s 2022 spring turkey season.

Field Test: Zeiss SFL 8x40 Binocular

When it comes to top-notch optics for hunting or bird watching, the name Zeiss certainly needs no introduction. The company introduced its first binocular in 1894; I’ll do the math for you — that means Zeiss has nearly 130 years of bino-building expertise.

Because I’ve been in the outdoor publishing business for nearly 30 years, I’ve had the opportunity to field test optics from all the major manufacturers. And I’ll let you in on a little industry secret: When such a field test is completed (usually over a predetermined time period, such as 2, 3 or 4 months), a writer/editor such as myself has the option to purchase the optic for a writer’s price instead of shipping it back to the manufacturer. It makes sense; the company can’t sell the optic as new because it’s been in the field, and it’s simpler to receive a check in the mail than a used product.

I mention this backstory because through the years — and many binocular field tests — I’ve purchased exactly one binocular on a writer’s price, a Zeiss Classic 8x30 bino in 1999. I was so impressed with the bino that I couldn’t part with it. More than 2 decades later, this bino is still going strong. Note: My brother has owned the Zeiss Classic 10x40 bino since the early 1990s and it’s still his go-to glass.

One of the author's hunting partners takes a turn glassing with the new Zeiss SFL 8x40 bino.
One of the author's hunting partners takes a turn glassing with the new Zeiss SFL 8x40 bino.

SFL = SmartFocus and Lightweight

I had the opportunity to field test the new Zeiss SFL bino during the lengthy spring 2022 South Dakota archery turkey season. SFL stands for SmartFocus and Lightweight. The SFL comes in two models — 8x40 and 10x40. Both are compact, measuring only 5.7 inches long and weighing 22.6 ounces. I tested the 8x40.

In addition to using the bino in the field every weekend of turkey season, I kept them handy in my living room to watch backyard songbirds, ducks, deer and other animals. My yard is adjacent to a hardwood river-bottom that often floods during spring, which means it’s loaded with wood ducks. 

This combination of testing — SoDak turkey hunting and Minnesota backyard glassing — enabled me to see what the new Zeiss SFL could do in a wide variety of lighting and weather conditions. I even used the bino to observe a total eclipse of the moon on May 15, 2022. With my backyard glassing, I often compared new vs. old Zeiss glass — the SFL vs. my 23-year-old Classic.

The author's old Zeiss 8x30 Classic bino has a tiny focus wheel; the new Zeiss SFL bino (above) has a massive and precise focus wheel, which makes it fast to find a bird or buck.
The author's old Zeiss 8x30 Classic bino has a tiny focus wheel; the new Zeiss SFL bino (above) has a massive and precise focus wheel, which makes it fast to find a bird or buck.

Testing Takeaways

You can visit the Zeiss website to read details about all the technical specs and features of the new SFL. The highlights specific to the Ultra-High-Definition (UHD) lenses include 90 percent light transmission, proprietary FieldFlattener technology, and LotuTec coating for a clear view even in rain due to its beading effect. These all work in concert to deliver a clear and crisp image with exceptional edge-to-edge clarity and brilliant color. Last but certainly not least, Zeiss says the new SFL is 30 percent lighter than competitors’ comparable models.

In no particular order, here’s what I liked best about the new Zeiss 8x40 SFL:

  • Focus is crazy-fast and precise. The focusing wheel goes from close focus (4.9 feet minimum) to infinity with only 1.4 rotations. Several times while working at my laptop this spring, I’d glance out my office window and spot a deer or some other critter that I wanted to quickly check out with a bino. I’d run from my office to the living room and then grab the bino, hopefully before the animal disappeared into heavy cover. No matter if the animal was at the back of my lawn, which is 40 yards from my house, or far back in the woods (about 200 yards), I could focus on the animal in a split-second with the SFL bino.
  • As darkness swallowed up the woods in my backyard, I regularly compared the new Zeiss 8x40 SFL to my old-school Zeiss 8x30 Classic, as well as a competitor’s mid-priced bino in 8x42. In all fairness to the mid-priced model, the SFL is much more expensive. I’m reminded of the saying “You get what you pay for,” which is typically true with optics. I sat inside my living room with all lights off, and tested how long I could identify a horizontal log at 125 yards. This log is about the thickness of a whitetail from backline to bellyline, and it’s surrounded by standing trees. I sometimes mistake this horizontal log for a deer when glancing out my window, so it’s an ideal test object. All three binos allowed me to see the horizontal log well after it disappeared from sight with my naked eye. As it got quite dark, I finally failed to identify it with both the modern mid-priced 8x42 bino and my old Zeiss 8x30. Note: With small 30mm objective lenses, my Zeiss 8x30 isn’t an ideal bino for low-light viewing. The Zeiss 8x40 SFL allowed me to see the log for several minutes longer than the others. Keep in mind that all binos allowed me to clearly see the log at the end of legal shooting light for big game (30 minutes after sunset). For true low-light scouting, however, such as trying to identify a big buck in a summer soybean field well after sunset and without the aid of a spotlight, the SFL is the real deal.
  • Earlier I mentioned the total eclipse of the moon on May 15, 2022. I noticed it beginning to take place while driving home from an afternoon fishing trip, and when the weather man on the 10 p.m. local news talked about the event and how it would be a total eclipse in the next half hour, I walked outside with the SFL bino to view it. I don’t own a telescope so I can’t compare the bino to that, but I will say I’ve never observed the moon with such clarity ever before. It was truly amazing.
  • During my time pursuing South Dakota turkeys, I relied on the SFL bino to spot roosted turkeys well before sunrise, and also identify distant birds (tom vs. jake vs. hen) after they hit the ground. My trusty Zeiss 8x30 weighs 20.5 ounces, and the new 8x40 SFL weighs 22.6 ounces, but keep in mind the 8x30 is really more of a compact bino than a full-size bino such as the 8x40 SFL. Perhaps nothing is more beautiful than a full-strut gobbler in the spring woods, and watching the various birds through new Zeiss glass was simply spectacular. As the rising sun hits the black feathers, a multitude of colors appears, and of course, at times the head of strutter could change in an instant from snow white to blood red. I loved watching the show through this top-notch bino.
Zeiss SFL binos have twist-up eyecups that are easy to adjust and stay in place after they're set to the desired height.
Zeiss SFL binos have twist-up eyecups that are easy to adjust and stay in place after they're set to the desired height.

I’ve listed a decent number of pros in this review, and honestly can’t think of a single con, unless you consider the MSRP of $1,799.99 too high. Is this a price-point bino? No. Is it a good value? I guess that depends on your income, expectations and demands in the field. 

I will say this: Even though I tested the new Zeiss SFL 40 bino for only 2 months, I’m confident in saying it’s a bino you can probably hand down to a son or daughter after you leave this world. Like my old Zeiss 8x30 Classic, which as I said is still going strong, the new offering from Zeiss appears to be every bit as solid. And finally, hunters should have peace of mind knowing that Zeiss stands behind their products.

Quote: “The Zeiss Limited Lifetime Transferable Warranty protects you against defects in workmanship or materials for the life of the product. If a defect that is covered by this warranty is found, Carl Zeiss will, at its option and without charge, either repair your product or replace it with a Carl Zeiss product of comparable specifications and value.”

Again, the new Zeiss SFL comes in two sizes, 8x40 and 10x40. If I spent most of my time west of the Mississippi, I’d choose the 10x model. For Midwest deer and turkey hunting, I prefer the 8x40. In the box you’ll receive a zippered case, neck strap, objective lens covers and eyepiece rainguard cover. I used the case only. In the field on hunts and scouting missions, I carry a bino on a shoulder harness and rarely mess with lens covers.

Perhaps you’re curious: Did I purchase the Zeiss SFL 8x40 on a writer’s price? Truth be told, the bino was in such limited supply during spring and early summer 2022 that there was no discussion with my Zeiss contact about keeping it. I promptly returned the bino at the conclusion of my field test period so the company could clean it up and then get it in the hands of another writer/editor. Frankly, I’m happy I didn’t have to make a difficult decision.

For more info on the Zeiss SFL binocular, visit


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