Buying monoculars can be slightly intimidating if your knowledge of optics is small. Hopefully, our buyer’s guide can educate you on monoculars and help you choose a solid device. Monoculars are single lens magnifying devices that come in a variety of different sizes and magnification ranges. Most optic’s companies produce a line or even multiple lines of monoculars, resulting in hundreds of different options.
Monoculars have some advantages over other optics for long range observation. Compared to spotting scopes and binoculars they are much smaller and lighter in weight. Spotting scopes are designed to be used with a tripod or bipod of some sort and are nowhere near as portable as monoculars. Binoculars are usually double the weight and size of a monocular simply because they utilize two lenses. Monoculars are the lightest and most compact option for optical devices. Some can be small enough to be pocketed even.
Monoculars can be used for different tasks. Due to their small size, they are easy to carry and lightweight enough to be worn around the neck comfortably. They are useful for casual bird watchers and getting a bird’s eye view of sports events.
Hunters, hikers, and outdoorsmen can make use of monocular for spotting, scouting, and gaining better situational awareness of the world around them. Monoculars are lighter than binoculars and easier to use on the fly than spotting scopes.
Monoculars could even be used by tactical elements like the military. Certain monoculars are outfitted with reticles to help soldiers call for indirect fire. Monoculars are quite versatile but are still very simple in their nature.
F.O.V. or field of view is the amount of space you can see between the left and right sides of your sight picture. Your natural field of view shrinks considerably when you look through a magnified optic. The general rule of thumb is the higher magnification the smaller Field of view you’ll have. A wide field of view makes it much easier to see moving objects. So a nice wide FOV is great for watching fast moving sports, like soccer or hockey.
Field of view is measured in feet or by degrees. When measured in feet the measurements are taken at a certain range. So, for example, the Bushnell Legend’s 10×42 monocular has an F.O.V. of 340 feet at 1,000 yards. When measured in degrees the degree reading stays the same at any distance. When reading degree F.O.V.s remember that the normal human F.O.V. is 114 degrees.
The magnification level of your monocular can range wildly. There is a fine line between a monocular and a spotting scope and that line is usually drawn at magnification. Magnification levels for monoculars are limited to a certain point. If a magnification level is too high the monocular will be almost impossible to use on the offhand. Too high of a magnification will result in a monocular jumping around whenever it’s barely even moved, including something as simple as breathing.
If you are a hobby bird watcher you may want a magnification level that’s on the higher side. This will allow you to see the vivid details of a bird. Someone watching a game of soccer may want a shorter magnification to provide a wider field of view, but they still have an increased view of the game.
Most monoculars will feature a fixed magnification range. Some variable models do exist, but they are often on the lower end of the quality spectrum. They aren’t necessarily poorly made, but may not be well suited for heavy field use.
If you look through a monocular that is held at about arms distance from you, you’ll notice a circle of light. This circle of light is basically your exit pupil. The larger the circle the larger in diameter your exit pupil is. When you actually bring the scope to your eye you’ll experience exit pupil by how bright the image is. Exit pupil is measured in millimeters and is easy to calculate. Simply divide the magnification level by the objective lens in mms. So, if the monocular is 10 power and the objective lens is 42 mms you’ll have a 4.2 mm objective lens.
Exit pupil is quite critical when it comes to viewing and observing in low light situations. Exit pupil size should align with eye pupil size. During the day the average person has a 3 to 4 mm pupil size, in low light situations that grows to 7mms. During low light situations the higher the exit pupil the better you’ll be able to see in low light situations.
Exit pupil during the day isn’t a major issue, and if you primarily use a monocular during the day it won’t be a major consideration.
When we talk about durability there are three different layers of durability. The first is the junk level. Junk monoculars that cost 10 bucks and are made in some far off land. They won’t survive a fall. Then we have general, which is your average monocular designed for bird-watching, sports viewing, and other tasks done on in civilization. These optics are generally water, fog, and shockproof as well as The third level is tough optics. These monoculars are specifically designed for durability in the great outdoors. These optics are designed to be dropped, kicked, submerged in water, and still keep kicking.
Hunters, hikers, and others certainly need super durable optics for their adventures, but the bird watcher may not. These tough optics are generally heavier and more expensive than your general optics and are well worth the extra cost if you need. Some of these extra features include rubber armored coatings, super tough lens coatings and are rated on the IPX scale for waterproofness.
Eye relief is the optic’s distance from the eye that the optic will provide the fullest picture at. Eye relief varies between monoculars and typically is not a major issue. Eye relief on rifle scopes is usually more important. The only real worry is for those people with glasses. Wearing glasses will cause some issues if the eye relief is too short and your glasses press the optic outwards. If you have glasses you’ll want to look for a monocular with adjustable eye cups to minimize distance issues.
Size and Weight
Here is one many people may not consider outright. A heavy optic can quickly become uncomfortable over extended periods of time because you have to hold it upright. Fatigue will call discomfort and tremors, which make easy viewing almost impossible. Also too big of an optic can make carrying it a hassle when paired with other gear. As we mentioned tough optics tend to be the strongest optics, and optics with higher magnification tend to be bigger. So when choosing a monocular take the time to examine and really know the weight, width, and length of a monocular when making your choice.
Digiscoping is the ability to mount a camera to your monocular and take photographs or show a wide display. Digiscoping is typically used with a spotting scope but has become popular with monoculars do to the small size and high performance of camera mounted phones. If this interests you, you’ll likely have to purchase a mount, and you need to ensure you monocular is compatible with your mount. This is only a small concern, but once you start digiscoping it can become addictive.
A good monocular is an excellent piece of lightweight and effective equipment for such a small piece of gear. They are remarkably affordable, and there is a wide variety of different options. The key to success with almost any optic is to match the optic to your needs if you do that you’ll be good to go.