For decades, birders, hunters, naturalists, and explorers have had two ways to magnify what we want to observe more closely. Binoculars are convenient to carry and provide moderate magnification, generally between seven and ten power—any more and they become increasingly difficult to hold steady. When more power is needed for distant objects or extremely detailed views of nearer things—a maddeningly difficult-to-identify Empidonax flycatcher, for example—we use a spotting scope, which provides significantly higher magnification: 20, 30, 40 power or more. But the scope must be mounted on a tripod to provide a stable image at those levels. Until now. We just spent a week with Swarovski’s astonishing AT Balance 18-45x65 spotting scope, which incorporates an internal stabilizing mechanism that allows rock-steady handheld viewing at any setting—leave the tripod home. The Balance scopes come in two models: the AT Balance we tested has an angled eyepiece, a 65mm objective lens, and a zoom range of 18 to 45 power; the ST Balance has a straight-through eyepiece, a 50mm objective lens, and a zoom range of 14 to 35 power. The former weighs 52 ounces, the latter 46. And since you’re already wondering, retail on the AT Balance is $3,999; the ST is $3,849.How does it work? From Swarovski’s site:The AT/ST Balance spotting scopes incorporate a moving lens that is adjusted by an electric motor (voice coil motor) to offset movements. These motors work particularly quickly, very precisely, and with low friction – the pushing and pulling movements are smooth and continuous. They are also used in applications such as camera autofocus systems. The integrated gyroscope sensor measures the current movement of the spotting scope. Based on this, a calculation is made to determine which lens movement is necessary to compensate for the motion to result in a stable image. With the stabilization concept of the AT/ST Balance also in movement there is no perceptible “floating” or “after-image,” which is key to the unique natural sense of vision. Automatic locking of the moving lens in the event of a fall or a sudden interruption in the power supply protects the lens while also ensuring the best optical quality by keeping the lens in the central position.
Each scope is powered by a 3.6-volt, 1860mHa rechargeable lithium-ion battery, claimed to last 12 hours of normal use between charges (via an external USB-C charger). The scope will enter a “time-out” mode after five minutes of non-use; tilting the scope (as if to focus on something) re-awakens it. However, there is no auto-off mode—you must turn it on and off manually via the switch under the eyepiece.That’s how it works. How well does it work? Superbly—with just a bit of a learning curve. On a recent clear morning Roseann slung the scope over her shoulder via the included strap and we bicycled up into the forest service land near our house. Before long we spotted a distant raptor perched on an agave stalk, not quite identifiable through my 10x42EL Swarovski binoculars. I turned on the scope (a two-second press on the switch), rotated the eyepiece to its lowest, 18X setting, and moved it to my eye. At that setting I easily confirmed the raptor as a red-tailed hawk—but more importantly as a motionless red-tailed hawk: the image was steadier than it was through the binoculars despite the nearly double magnification. The learning curve resulted from the fact that it was a bit challenging to hold the scope while keeping my eye at the correct distance from the eyepiece to ensure a full field of view. However, I quickly found that by lightly bracing the outer edge of the eyepiece against my eyebrow and the bone beneath, I could easily stabilize the eye relief to maintain a full view. Roseann employed her thumb as a brace to do the same thing. We both remarked on how much faster the stabilized scope was to deploy than a standard spotting scope on a tripod—it’s nearly as fast as a binocular, and the ST with its straight-through view would undoubtedly be even faster. For rarely still subjects while birding the advantages of this cannot be overstated. More learning: at 18X the 65mm objective lens of the AT provides a comfortably wide 3.6mm exit pupil. Bumping the power all the way up to 45X brought the hawk leaping even closer, but shrank the exit pupil to just 1.45mm, requiring careful positioning of my eye to avoid vignetting. (Note that this is true of any scope or binocular; the exit pupil is a function of objective diameter divided by magnification, no matter what you’re looking through.) Later figuring revealed that the exit pupil of the ST Balance 14-35x50 is virtually identical to the AT at its respective lowest and highest power. Of course the larger objective lens of the AT gathers more light so it is brighter at any setting.More viewing convinced me that the sweet spot of the AT 18-45x65 resides between 18x and 30x for most use, with that 45X setting reserved for really challenging, distant subjects in good light. I suspect, but have yet to confirm, that the AT’s similar strength would lie between 14x and 25x.Lest I neglect other aspects of the AT 18-45x65, I should note that the optics appeared to be every bit the match for our non-stabilized Swarovski ATX95 spotting scope, with allowance of course for the smaller objective lens of the stabilized model. Sharpness and color fidelity were simply above reproach. Despite the complex electronics, both stabilized models are weatherproof to IP68 standards, i.e. completely dust-proof and immune to heavy rain or even immersion. Both scopes incorporate a safety function that locks the moveable lens in place instantly in the event the gyroscopic sensor detects that the scope has been dropped. Also note that both scopes will work perfectly with a flat or missing battery; you just won’t have the stabilization and will need a tripod.Full disclosure: I wondered at first if the AT/ST scopes were a solution to a problem that didn’t exist. After watching Roseann carrying this one slung comfortably over a shoulder while riding a bicycle, then enjoying perfectly stable handheld long-distance views of wildlife, I changed my mind. But my final thought came totally out of left field. As I was reluctantly packing up the AT Balance to ship it back to Swarovski, I looked at it and abruptly thought, Jack Aubrey would have swooned to look through this thing from the deck of HMS Surprise.
