Binoculars are the primary tool for birding, and even with a spotting scope there will always be birds too far away to identify. But so many people gasp when seeing even a common bird through a scope for the first time; there really is something so satisfying about it! On many occasions an identification couldn't be made without much more magnification than a binocular can provide. These include seabirds far out on the ocean, waterfowl on bays, shorebirds scattered over mud flats, and distant perched raptors.
Even if you can clinch an ID, we've all experienced the vague dissatisfaction of a just-barely-seen field mark on a bird too far or too obscured. The experience even has a name: "BVD", or better view desired. And a tripod-mounted spotting scope can take you to that next level. Birders may also put a scope on a car window mount, utilizing the car as a blind.
I know buyers may be intimidated by all the models and choices: angled or straight, small objective or large, fixed power or zoom, ED or not ED? Read on and we hope to help you choose!
The first choice is whether to get your spotting scopes with an angled or straight eyepiece. Each has its advantages and disadvantages; for more details, please see the separate blog post on that subject. I'll distill it down for you: over the years angled has come to be so popular among birders (>95% at CMBO) that we no longer stock straight scopes; they're special-order only. For most of you, that's one decision down.
Another decision that's much easier today is whether to buy a fixed power eyepiece or a variable or zoom eyepiece. Through the 1980's, most zoom eyepieces ranged from poor to terrible. Fixed 22x or 30x wide angle eyepieces were wise choices then, and still options now. But zoom eyepieces have really improved, and today most scopes come with a zoom eyepiece by default. Even entry- to mid-level scopes offer eyepieces that are functional through the lower two-thirds of the range. Just don't expect to use the maximum magnification in any but the highest quality optics.
If you are a birder, you have probably now decided on at an angled scope with a zoom eyepiece. Progress!
The next decision is what "size" to get, size in this case referring to the diameter of the objective lens. In most brands, spotting scopes range from 50 mm to 85 mm. A few makes go up to 88, 95 and even 100 or 115 mm.
The larger the objective lens, the more light it collects, and the greater the resolution, which allows for higher magnifications. But of course the increased size comes with increased weight. A Kowa TSN-501 (50 mm) weighs just 14 ounces, while a Swarovski 115 mm objective with the BTX binocular ocular tips the scales at 7.75 pounds. Most options are in between.
You should also consider the scope size and its support together. Most of the time, "support" means a tripod. That's what makes it usable at high magnifications. Carbon fiber legs are lighter and quieter than aluminum; they're also more expensive. Depending on objective size, a combined scope plus tripod and head weighs anywhere between five and thirteen pounds. Also keep balance in mind; think twice before putting a massive scope on a super lightweight tripod. Don't skimp! Putting a great scope on a cheap tripod yields an unsatisfactory experience. The $79.95 tripod may only last a couple of years, but it may seem longer due to frustration. A well-built tripod in the $220 and up range can serve you well for 20 years.
Many scopes smaller than 60 mm are marketed as "travel scopes". That means they are lightweight and compact, so they'll fit in a carry-on for air travel, or in a backpack if you're headed to the Central Park Reservoir. Some, such as the Celestron Hummingbird, can be hand-held at low power. Travel scopes can also be mounted on a monopod or lightweight, compact tripod. They have the advantage of extreme portability and are a great alternative to not having a scope with you. But they won't provide the same brightness or power of a full-sized 65 mm to 95 mm model. If the weight dissuades you from taking it out, then go smaller and lighter. As others have noted, a scope in a closet or trunk is of no value.
In selecting from among the 65 to 95 mm range, be guided first by how you will use the scope, and second, by your stature and stamina. If you will mostly be hauling it in and out of the car on an auto-tour route, or walking a couple hundred feet to an overlook, then size and weight don't matter. So go full-size. If it's important for you to be able to ID storm-borne seabirds, you will be better served by a scope of 80 mm or more, with ED glass.
If, on the other hand, you plan to regularly hike a mile and a half to a mountain hawk watch with a 500-foot elevation gain, or trudge several miles on a beach, then weight might be an issue and a 65 mm might be perfect for you.