Choosing the right monocular can be tricky, especially with the range of devices you’ll find with a simple Google search. It can be beneficial to spend a little time educating yourself on the differences in monocular devices, decide how you’ll be using your device the most, and try to handle a few different styles to see what feels and fits best. We’ve devised this guide to help you determine ahead of time how to get the most from your purchase.
Related reads: a rundown of our favorite monoculars for 2019
This is a good question to ask yourself before you buy a monocular. Many people find binoculars or spotting scopes superior because of their depth of field and magnification power. But this isn’t always a bonus if you don’t need a high-powered device. A monocular is half the size of a pair of binoculars, and a fraction the length of a spotting scope. They only use a single focal path and one objective lens and eyepiece. This means they’re much lighter and more portable, and easy to slip into a pocket, purse, or glove compartment. If you need more power, or if you’re planning to spend a lot of time glassing, binoculars or a spotting scope may be your best choice. But if your goal is to spot quickly and for short periods of time, or if you’ll be on the go, a monocular will fit the bill.
As with most optics, you’ll see a set of numbers on your monocular that designate its magnification strength, such as 8×20. The first number means you’ll achieve 8 times magnification; the second number means your objective lens is 20mm in diameter. Remember that more magnification isn’t always better. It will narrow your field of view and can make your image shakier. On the other hand, larger lenses are most beneficial in low light scenarios, as they gather more light into your device. Most monocular devices average around 6x-15x magnification (though most commonly they are 7x) and 20mm-50mm lenses. Because a monocular contains a single light path through its objective lens, it does limit image depth to a 2-dimensional field. But with the bright image quality you can expect from a monocular, this usually isn’t a problem. Treated roof prisms and multi-coated objective lenses will also add to your image quality, so check the specifications on your model before you purchase.
One of the great benefits of a monocular is night vision capabilities, which can be achieved for a reasonable cost. With built-in infrared or thermal imaging technology, you can illuminate the dark and seek out those elusive nocturnal birds and animals. Night vision typically means less magnification strength, otherwise, you’d end up looking at a blurred mess. 5x is a standard strength for good night vision. You’ll also want a nice large lens for optimal light gathering in the dark.
An often-overlooked component of a monocular is its close focus range. This is the point at which you gain clear magnification. You may not get clear focus on a spotting scope until you hit a 20-foot distance, but a good monocular can have a close focus of a mere 20 inches. This can be helpful for instant focusing for birders, or for finding your target when hunting.
Below are several common activities in which people find a monocular beneficial. We’ve provided suggestions as to what specifications you’ll want in a monocular for each activity to help you whittle down your choices.
You’ll probably want a good magnification strength when observing nature, especially with skittish wildlife. A 10x magnification will ensure you can stay well-hidden from distant animals, and a wide lens for low-light forested areas, such as 40mm, is ideal. Also, search for a durable, rubber-shelled and waterproof device to make sure it stands up to weather and rugged environments.
We also have a guide on the 5 best monoculars for hiking
Too high a magnification strength for birding can be bothersome, as you might end up with a shaky image while you’re trying to observe a bird up close. An 8x magnification is best, as well as a wide field of view for spotting and tracking moving birds. If you’ll be in a heavily treed area, you may lean toward a larger 40mm lens size, as well, to get the best brightness.
We also have a guide on the 5 best monoculars for birding
Tracking moving game can be a challenge, especially with a spotting scope fixed on a tripod. Many hunters utilize a monocular along with their spotting scope to keep an eye on their targets more efficiently. For hunting, you’ll want a nice wide field of view (so not too high on the magnification) and a large lens for good light. As with any wildlife watching or sporting, you’ll want to look for a durable model with a good rubber shell to keep it protected from bumps and bruises.
We also have an article where we review the 5 best monoculars for hunting
A lot can happen on an active field, arena, or concert stage, so make sure your device has a decent field of view. An 8x magnification is probably best, and no higher than 10x. You’re also likely to be in a well-lit area for outdoor or big stadium events, so don’t go too high on the lens width. Lean toward the mid-range (around 40mm) for best performance.
As mentioned above, you can find a great night vision monocular for a reasonable price. Most of these have less magnification power and a large lens diameter to optimize light-gathering in the dark. A 5×50 monocular is perfect for most infrared viewing, as you’ll get the clearest image.
You can find a good quality, mid-range monocular for anywhere between $100 and $300. If you want digital capabilities, you’ll fall in the top of that range and higher. Night vision is a little more expensive, though still reasonable. Plan to spend $200 to $300 on a mid-range infrared monocular.
Before you decide, hit your local sporting goods or optics store to check out your options. Now that you know more about choosing a monocular, your final step is to try them out. You might find that 8x magnification just isn’t going to cut it for birding, or that its field of vision is too narrow for your preference. You might also learn that the model you loved online is just too heavy or bulky, or the optics aren’t bright enough. Take your time to find the best fit for your needs. When you finally make the plunge, follow a careful cleaning regimen (the same as you would for binoculars or a spotting scope) to keep your lenses free of debris, and keep your device tucked safely in its carrying case between uses. A monocular is a great investment. Take good care of it and it’ll provide endless hours of quality glassing.
Top image credit: Vitaly V. Kuzmin, Wikimedia
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