It was a quest: Discover the one binocular to own, if we could own only one. It had to work for skywatching (we're Space.com, after all), but the ideal binocular also had to be flawless for outdoorsy folks, sportspeople, concertgoers and adventurers of any type. It needed to be small, but powerful; bright but free of color distortion. And we wanted to see if we could get all this for less than $500. We think we found one.
Like many amateur astronomers, I use binoculars to help locate objects and a telescope to examine them in detail. That requires the "bins" to be compact; out of the way when fiddling with the 'scope, but right there when we need them to scan the sky. We crave high contrast to see dim stars. We don't want false-colored edges around planets or the moon. The binocular must be lightweight enough for hand-holding and not have the dreaded "jitters."
And, because humans do not live by starlight alone, the ideal binocular must work for all the daytime activities we wish to magnify: sports, games, boats, performances and other events. The three largest groups of binocular buyers are bird watchers, sport hunters and skywatchers.
One binocular to woo them all? Enter the Oberwerk 8x42 Sport ED model.
ED stands for "extra-low dispersion" glass. It's what separates wannabes from serious optical instruments. ED glass is formulated by adding fluorine, zirconium, titanium or other rare-earth elements to the silicon. In comparison to cheaper glass, ED crystal transmits more light and prevents that light from splitting widely apart into its constituent colors.
When light passes through a lens, it bends. The shorter the wavelength (more towards blue and violet), the steeper the bending. As the colors are split out of white light, they "land" in different places. Your eye can only be in one place along the path. The result: you see blurry colored edges on objects. ED glass better-aligns the colors together. Your eye and brain resolve these properties into sharper, brighter, higher-contrast and more richly colored images.
'Porros' vs. 'Roofers' vs. 'Galileans'
It's a common — but questionable — belief that binoculars for astronomy must employ the blocky, angular "porro" prism design. Being larger, "porros" can concentrate more photons for greater illumination. "Roof" prisms, on the other hand, are usually lighter in weight and let the binoculars be smaller because they fold the light path, doubling it back within the prism's dimensions.
If the goal is to look primarily at day-lit objects, most buyers will go for "roofers." Indeed, 56 percent of binoculars sold worldwide in 2017 employed roof prisms. But if the targets are mostly dim dots in the dark (astronomy), the porro geometry can deliver more light to users' eyes. So, "porros" for skywatching and "roofers" for everything else, right?
Well, the truth is much more complicated. If observing only with binoculars, many astronomers prefer a pair of identical refractor telescopes fused together, side by side. (Not to be snooty, but this is the only time the word "pair" is technically correct when referring to a binocular device.) This third type of rig is called a Galilean binocular. They are very large and heavy, so must be mounted on a tripod or counterweighted arm.
Among smaller and handheld astronomy binoculars, porro prism designs are most common. But a few optical engineers have found ways to select materials for — then cast, coat and install — roof prisms that can rival and surpass many porros under the night sky.
Oberwerk has done exactly this with its model 8x42 ED. But the company has succeeded at a low enough manufacturing cost to hit an eye-opening price-performance ratio: sturdy, lightweight, waterproof binoculars, pulling in sharp celestial and terrestrial views, with no color-fringing, for about $320.
Typical of Oberwerk, there's a certain rugged, "mil-spec" (good enough for military battle conditions) feeling to these binoculars: a hardy hunk of instrument, but not too heavy. They balance nicely; the center of mass sits right in the palm(s) of your hand(s).
Oberwerks are generally built to last, and this model shows no deviation from genotype. They can take a shock. Parts that would be plastic on comparable brands are old-school metal. The oversized (that's a feature, not a bug) focus knob is a prime example: It's aircraft-grade aluminum, deeply knurled for fingertip traction. Its glide is sweet, not varying much in feel between Arizona daytime heat and New Hampshire nighttime chill.
The right-eye diopter adjustment-ring is similarly robust. There's a tiny tick mark, indicting the neutral-focus position, dug into the ring. For those among us who are farsighted (me), it's difficult to see this little incision without eyeglasses. There's also no numerical scale — just +/- marks and a null arrowhead molded into the optical tube cover. As a practical matter, you won't often need to reference any of this; you'll just intuitively focus. But if two (or more) of you are passing one binocular back and forth, it can be nice to know one's own precise correction (admittedly, a rare case).
Both "twirly parts" are anodized in fire-ember red, a striking and beautiful contrast against the deep-woods-at-night, green rubberized ("waterproof") body. That choice is not driven solely by style; the red rings are Oberwerk's way of declaring that extra-dispersion ("ED") glass lives inside.
Adventure travelers need a binocular small enough to tuck away and lightweight enough to hold up to the eyes without shake. Gyro-stabilized binoculars from other manufacturers can eliminate the "wigglies." But they're heavy, because you're lugging batteries in addition to optics. And they are bulky, because they have to house motors and mechanisms. In contrast, Oberwerk's solution is a meticulous blend of low-mass chassis material, quality component selection and exquisite design.
If you're a seat-of-the-pants amateur astronomer (like me), you enjoy scanning across the sky for many minutes, letting your eye catch on some enticing ensemble of stars worthy of probing more deeply with your telescope. Oberwerk's magnesium-alloy construction lets these "bins" weigh in at less than a pound and a half [1.48 pounds; .67 kilograms]. You can hold them for many minutes without quivering views due to twitchy muscles.
For sustained wide-field viewing, you can easily put them on a tripod. A knurled plastic knob at the front unscrews to reveal a standard ¼"-20 threaded collar. You'll need an adapter stalk, available from third-party sellers.
In the daylight, the undesirable phenomenon of "chromatic aberration" can darken your mood when you're trying to appreciate the intricate patterns of a colorful bird's feathers. Or to see if that young deer, 100 yards away, has lost its fawn spots. Or to enjoy the textures of the brickwork on that Chinese architectural roofline. But the Oberwerks are free of color smear, can handle all of these situations well and can pass on undistorted edges to your eye.
Under the stars, the ED glass shows its stuff: The Oberwerks gather a lot of light for their small-ish 42mm (1.7 inches) apertures. If there's any chromatic irregularity at all, I couldn't detect it. In other binoculars, that issue pops up when a lens (or multilens system) can't bring all colors to converge at the same point. You see it as blurred fringes at the edges of objects; a reddish ring around the moon is a typically unwelcome case.
8x magnification isn't a lot: At night, you won't be able to resolve the famous color dichotomy in the blue-orange "double" star Albireo (Beta Cygni). You'd need truly huge binoculars for that, at least four times more powerful. But you can easily detect the subtle color differences between the butterscotch of planet Mars and its redder rival star Antares (whose name, in Greek, means "opposite of Mars").
The 8.1-degree field of view is quite serviceable for finding targets in the sky. Orion the Hunter's belt, dagger and sword neatly fill your oculars, with the well-known Orion Nebula occupying about one-sixth of the scene. Castor and Pollux, the two stars of the Gemini twins, cover exactly half the cone of sky funneled to your eyes.
If you crave a slightly tighter view, Oberwerk offers a 10x42 ED variant with a 6.5-degree field.
It's no different in weight or size from the 8x42's. Merak and Dubhe, the two stars in the Big Dipper, which point to Polaris (the North Star), fit just within the 10x42's field. Either model is wide enough for meteor showers; simply lie back in your chair, point them toward the radiant and wait for your shooting-star quarry.
Both these Oberwerks work for the very (almost infinitely) distant. But what about that tiny bird in the bush just a few yards away? These binoculars focus closer than any other I have used. Period. Ridiculously close: Sitting at the breakfast table, I was able to focus on my son's eyebrow, less than 7 feet away. Optical witchcraft!
The 8x42s are magnificent at concerts and shows: powerful enough to haul in the $450 view for the $65 ticket price; small enough not to bother anybody around you; simple enough to avoid arousing the suspicious eye of the security detail; and light enough for you to hold up for most of the show.
One of our few complaints is that one or the other eyecups sometimes pops off, adhering to the lens cover set as you remove it. But it's a simple matter to slip its rubber skirt back into place. (Editor's note: The manufacturer reports that this issue has been fixed: "earlier units came from the factory with a combination of weak glue and oil on the twist-up mechanism- which caused the eyecups to come off easily.")
There's enough "eye-relief" (that's the distance from the diopter to the exit pupil) for nearsighted users to operate these bins comfortably with their eyeglasses on. But there's enough adjustment in the focuser that they may not have to.
A lot of binoculars look the same. Let's face it; Many different binocular "manufacturers" produce their wares in the same two or three Chinese factories. But varying levels of care and attention put into the individual design, materials selection and quality control make huge differences in the resulting products, even if, on first glance, they look nearly identical. Oberwerk lies at the obsessive end of the scale.
There are at least five other brands offering various 8x42 "roofers." Several appear superficially similar to the Oberwerks, for example: Nikon's 7576 Monarch 8x42s. But none are created equal. Most are next-to-useless — substandard "gotchas," in my opinion.
Some, like Olympus' Magellan 8x42 EXWP, step up to good-quality glass. But few will be as clear ("transmissive") as the Oberwerks; so, your targets will be dimmer. And none are likely to be as free of spherochromatism (though we have not tested them all).
At the high end of the market, you may find 8x42s with a bit better performance in certain specific ways, but they will be at least three times the price of the Oberwerks. The German Leica 8x42 BN binoculars, for example, can pull a little more starlight. The Leicas give richer contrast on dim "fuzzies" (think comets, or the Andromeda galaxy, or the M44 cluster). And they are a little more sharp. But you won't be able to handhold them as long; they weigh half again more than the Oberwerks. And the Leicas suffer from aberrant magenta/green color splitting. The Zeiss 8x42 Victory SF and the Swarovski 8.5x42 EL binoculars are nearly perfect, but either one will cost well over $2,500.
One binocular to rule them all
No matter how much — or how little — you have to spend, it makes sense to have one "grab-and-go" set of binoculars that you can trust to bring all the world's detail in closer; night or day, indoors or out. With their compact size, chunky-but-lightweight feel, superb clarity, lack of color distortion and precise focus, we believe that Oberwerks' 8x42 ED is the one binocular to have if you can have only one.
- Best Binoculars for Astronomy, Nature, Sports and Travel
- How to Choose Binoculars for Astronomy and Skywatching
- Best Telescopes for the Money - Reviews and Buying Guide
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Dave Brody has been a writer and Executive Producer at SPACE.com since January 2000. He created and hosted space science video for Starry Night astronomy software, Orion Telescopes and SPACE.com TV. A career space documentarian and journalist, Brody was the Supervising Producer of the long running Inside Space news magazine television program on SYFY. Follow Dave on Twitter @DavidSkyBrody.