Expensive versus affordable binoculars—what’s the difference?

WWhen I started birding at the start of the COVID-19 pandemic, I couldn’t believe that I had just discovered, in middle age, the joys of bird watching. It was the perfect hobby. I could watch birds anywhere. And I could do it practically for free. I already had the only equipment I needed to get started: a pair of good entry-level binoculars that could magnify small or distant birds to better see their identifying features and appreciate their beauty.

At first I was perfectly happy to use these binoculars. Before long, I had accumulated my first 100 species (“in perpetuity” in bird enthusiast parlance) with them. Life was good. But one day, out of curiosity, I tried two much more expensive trash cans from the locked display case of the local sporting goods store. Thanks to them, the world seemed so much brighter, sharper, better. I could see the individual hairs of the stuffed moose on the other side of the store. I didn’t buy these binoculars that day, but I knew that as soon as I could invest in top-notch optics like this, I would.

Finally, I took the plunge and bought a pair of…sip— $3,200 Swarovski Optik NL Pures, which many consider to be the best binoculars on the market for bird watching. My original bins, a Celestron NatureDX pair that cost less than $200, still see much use, living as they do on the kitchen windowsill, within easy reach whenever an interesting bird visits the garden feeder while I’m doing the dishes. But it’s the new ones that I take with me into the field on dedicated birding escapades.

On supporting science journalism

If you enjoy this article, please consider supporting our award-winning journalism by subscription. By purchasing a subscription, you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

I love these binoculars. They’re a joy to look at and use and, more importantly, I feel like they help me see so much more. I admit, however, that I wonder if the price is justified. What exactly separates binoculars that cost thousands of dollars from those that sell for an order of magnitude less? I decided to find out.

A few decades ago, this question was relatively easy to answer because binoculars were simpler, according to Steve Sosensky, content manager for Optics4Birding, a supplier of birding optics. “There have been so many improvements over the last 30 years,” he says.

Basically, binoculars are two small telescopes mounted side by side to allow the viewer to make long-distance observations with both eyes instead of just one. Each “telescope” contains large objective lenses at the front end of the barrel to collect light, faceted elements called prisms in the middle that refract the light to correct the inverted image produced by the objective lenses, and an eyepiece at the rear made up of smaller lenses that enlarge the image.

There are two general types of binoculars, based on two different configurations of the prism system. Porro prism binoculars, named after their mid-19th century Italian inventor Ignazio Porro, feature offset prisms that take up a lot of space, making bins bulkier. Roof prism binoculars, on the other hand, have prisms arranged such that they create a straight line between the eyepiece and the light-collecting objective, giving this style of binocular a slimmer shape. Porro prism binoculars inherently transmit light better, produce a bright and faithful image, and are easier to manufacture. Roof prism binoculars, developed around the turn of the 20th century, are more durable and easier to weather, but they lose some light when passing through the prisms.

Manufacturers have come up with a host of new features to make their binoculars brighter, more precise and more durable than ever: glass prisms containing barium oxide to bend light without scattering it; “phase correction” coatings for prisms to improve light transmission; glass lenses containing the mineral fluorite to reduce color distortion; external lens coatings to resist scratches and repel water, oil and dust; nitrogen or argon pumped into the body of the binoculars to replace the moisture-laden air and thus prevent the formation of internal fogging; Magnesium chassis for durability.

Albert Fiedler of Swarovski Optik, who has worked as an optical designer for 25 years, notes that one of the biggest advances he has seen in that time is the development of a “field flattening” system that makes the image sharp all the way to the edges. “Such systems are well known in astronomy, but only at very high magnifications. We have made such systems with magnifications of 8×, 10×, 12×,” he says, referring to the magnifications typically found in binoculars for wildlife observation. In another major advance, they have significantly reduced the weight of their largest spotting telescope, a device that offers much higher magnification than binoculars, simply by changing the spacing between the three objective lenses.

Dan Cooper’s birding friends confirmed his hunch: “You don’t really need to spend $2,500 anymore.” »

The more bells and whistles a pair of trash cans had, the more expensive it was. If you were buying binoculars back then, you’d need to shell out $500 for a decent pair and several times that amount for the top of the line. That’s what conservation biologist and ornithologist Dan Cooper of the Santa Monica Mountains Resource Conservation District in Calabasas, Calif., did in 2009 when he purchased a $2,500 pair of binoculars from Leica, which is considered one of the leading manufacturers of binoculars and other sports optics, along with Swarovski Optik and Zeiss.

But in 2016, when Cooper began testing and reviewing binoculars in the $150 to $350 range for Wirecutter, the manufacturer’s product recommendation service. New York Timeshe was surprised to find that the market had changed. “I was like, damn, this is all pretty good,” he says. His birding friends confirm his hunch: “You don’t really need to spend $2,500 anymore. » Cooper’s top pick of the binoculars he tested, the first-generation Midas model from Athlon Optics, has many of the same features that were once reserved for the most expensive binoculars. Yet they only cost $250. And 10 years after I started reviewing binoculars in this price range, they still come out on top.

Yet in some situations, Cooper says his Leicas have the edge over the Athlons. “If there’s a small bird very far away in bad light, I’ll use my Leicas because they have a lot more color accuracy and sharpness at those far distances,” whereas the cheaper models get a little muddy at the edges of the image. Expensive binoculars, with their better build quality, won’t break as easily, he adds.

Meanwhile, binocular technology continues to advance, although it may not be as spectacular as it was a quarter of a century ago. When Fiedler was designing the NL Pure line, which debuted in 2020, he was trying to improve on a predecessor that was already considered the benchmark. It focused on expanding the field of view, width and height of the section of the image visible through the binoculars.

A wide field of view is desirable for bird watching because it makes it easier to find a bird in dense foliage or in the sky and to track a moving bird. Ultimately, Fiedler and his colleagues developed a 70-degree apparent field of view, the widest available in this class of binoculars, which required a lot of fine-tuning to eliminate the accompanying optical aberrations. And they improved the ergonomics, refining the focusing mechanism to make it smooth but precise.

Fiedler believes there is still room for improvement. Perhaps additional adjustments to the arrangement of lenses in the objective could reduce the diameter of these lenses and thus the weight of binoculars and spotting scopes. Perhaps they could develop a carbon case, known for its durability and lightness, and remove the rubber armor that protects the instruments from impact, he suggests. “Just let me dream.”