Binoculars are an essential piece of gear for any outdoorsman. They help you scout the environment around you and easily notice things that are further away, and you wouldn’t otherwise notice with the naked eye. Regardless of whether you’re just enjoying the view, or looking for something in the distance, they’re a must-have.
The problem with binoculars is that most of them tend to be big and bulky. If you’re already carrying a huge backpack full of multi-day gear, that won’t be a problem. But if you’re trying to travel light, and not carry too many things, a pair of binoculars might weigh you down. This is where small binoculars, also known as compact binoculars, come in. They are a fraction of the weight and size of a regular pair, yet come with much of the performance of one. If you need or want, the advantages a pair of binoculars can offer but don’t want to put up with the weight and size of them, you might want to check out a pair of compact binoculars.
To begin with, we need to make a clear definition of what compact binoculars are. They’re basically small binoculars that you can fit in a purse or even a large pocket, and they have a small front lens. That small front lens is generally 26mm or less. There are some that have a 28mm lens, but they’re pushing it a bit in terms of size. You might not be able to fit them in your pocket or purse that easily. They’re excellent for sports as well, things such as cycling, skiing or canoeing, where you don’t have a lot of room for accessories. Just like regular binoculars, they have a few advantages and disadvantages. But if you’re limited in terms of storage capacity, they’re the ones to go for.
Buying a pair isn’t that easy. However, at one point in time, good binoculars, especially compact ones, were fairly expensive, which put them out of reach for many. Nowadays, there are many brands that make great binoculars that won’t break the bank. There are both reputable manufacturers, such as Nikon and Zeiss, and some other, less-known ones, such as SkyGenius. The thing is, not all of them are worth it. With the sheer number of options available, how would one know which one is?
Well, we’re here to help you find the best compact binoculars for your needs. There are a couple of options we’ll take a look at, and we’ll leave it to you to decide which ones fit your requirements best. If you still aren’t sure which ones to go for, we have a buyer’s guide for compact binoculars as well, to make things even easier. Read on, and by the time you’re done, you’ll easily be able to make an informed purchase decision.
At a Glance
We’ll start things off with a product by Nikon. Nikon is widely known as experts in the optics field, with roots going back to 1817, where the first binoculars were developed. Ever since, Nikon has given us products that are increasingly impressive, and perform admirably regardless of the conditions. Such is the case with their Trailblazer 10×25, a pair of compact binoculars that are built incredibly well, fold into an even smaller accessory, and give you optical clarity that puts them on par with many of the world’s best compact binoculars. Let’s take a better look.
To begin with, the Trailblazer 10×25 has a 10 times magnification. This is a number that will let you get very close to your subject. You might expect image quality loss, with this being a pair of small binoculars, but that isn’t the case. You get the stellar performance and clear and sharp images. That’s also due to the 25mm lens, that lets in plenty of light. The combination gives you a 2.5mm exit pupil, as well as 10mm of eye relief. The field of view at 1000 yards is 342 feet, which is fairly wide.
This is a roof prism design. It’s not just any roof prism – you have BAK4 high index prisms. They give you high-resolution images with plenty of sharpness and contrast. This is the most advanced prism solution at this point, and Nikon are clearly taking advantage of that. The optics are multi-coated. Multiple anti-reflective compounds layers ensure that both brightness and resolution are stellar, and you can easily see your target.
On the outside, we have a double hinge design. This lets you fold down both eyepieces into a very compact scope, and put it in a small pocket. In the middle is the central focus knob, which is very smooth. It lets you focus easily and quickly, for quick viewing, and if you’re careful, you can also easily adjust focus very precisely as well. The compact binoculars are completely fog proof and waterproof, with both O-rings and nitrogen filling. They won’t fog up, regardless of the conditions, and you don’t have to worry if you get caught up in the rain. They’re durable, and have a rubber-armored coating on top. This ensures a good grip, which won’t slide even in wet conditions.
To wrap things up, this is one of the best compact binoculars you can get today. Incredible optics, stellar build quality, and a price that won’t give you a headache all make for a winning combination. If you’re after a pair of small binoculars that you can throw in the bag, and forget it’s there, this is the one to get.
2. G4Free 12×25
At a Glance
Even though the Nikon Trailblazer gave you incredible value for the price, some might argue that it’s fairly expensive. If you’d rather stay at the lower end of the compact binoculars range, and get much of the performance, the G4Free might be a good alternative. You’ll also be getting a tad more magnification, so if that’s important, read on and see whether you should be ordering this pair of compact binoculars.
To begin with, let’s discuss the numbers. 12×25 is a common size with binoculars, but admittedly, some brands do it better than others. With a magnification factor such as 12 times, and a binocular that is this small, you might easily notice image quality loss. Most notably, there will be loss of sharpness at the edges, and the whole image might seem faded. However, that’s not the case with the G4Free, which has a multilayer composite green film. It ensures that performance is stellar, and you’ll be able to use it, even in darker situations. The 25mm lens does let in plenty of light, just like with the Nikon, and should be enough. You get fully multi-coated optics as well, which isn’t something you find often with products on this end of the price range.
Unlike the Nikon, we have a Porro prism here. We’ll talk more about that below, but what matters is that it’s a BAK4 prism. This ensures optimal light transmission and clarity, and gives you the highest possible image quality. Color fringing is minimized as well, which is very welcome.
Moving on to the outside, one thing you won’t find with many compact binoculars is the diopter adjustment. There are two focus knobs, one at the center, and another one within the right eyepiece. First, you close your right eye, and focus what your left eye sees, with the center knob. Once the image is in focus, you close the left eye. You focus what your right eye sees with the right eyepiece. You should note the diopter scale’s setting, for later on. Both sides are now in focus with the left and right eye accordingly, and you’ll only need the center focus knob if you need to readjust. This is a nifty feature which comes in handy.
Now, a downside is that there’s no indicated waterproofing rating. They might hold up in a pinch, but we wouldn’t recommend using these in the rain. Fog proofing is also questionable. However, when you consider the asking price, you shouldn’t really be complaining too much. It’s a great pair of compact binoculars that doesn’t cost a lot. They’re perfect if you want something that’s cheap and won’t make you feel bad if you damage it. Or, if you want to give your kid a reason to go outside more often, buy it as a gift. It’s compact, lightweight, and optical performance is great– they’ll surely enjoy it!
At a Glance
With the Wingspan Spectator, we have somewhat of a middle ground between the previous two options. It’s an excellent pair of small binoculars for bird watching, or similar outdoor activities. It has a few things going for it that might make you want it. You will get a lot of high-end features, as well as decent build quality, but the price is nowhere near the high-end offerings. But, is the Spectator worth it? Or should you really get something that’s a touch more expensive and get it over with? Let’s find out.
To begin with, we have an 8×32 pair of compact binoculars. You might find this weird, but it is actually a great combination, provided it fits your need. 8x magnification is still plenty, and you will be getting a 362 feet wide field of view at 100 yards. For bird watching or just sightseeing, this should be quite a bit. Unlike the smallish 25mm lenses, you now have a 32mm one. This does mean that there’s a small, yet noticeable impact on the size and weight of the binoculars. They come in at 15.2oz. However, the light that can enter the scope makes things more than worth it. You will get a bright, vivid image, with plenty of contrast. Last but not least, there’s a 3m close focus. If you’re getting a pair of compact binoculars to see objects that are close, but you want to zoom in, this is a great option.
In terms of optics, there’s a BAK4 prism, which gives you plenty of quality and clarity. There’s no mention of coating here, so chances are there isn’t a fully multi-coated lens inside of the Spectator. This is a tradeoff which explains the price difference with something like Nikon’s Trailblazer. Apart from that, optical performance is stellar, better than other midrange alternatives, and certainly better than the budget options.
On the outside, there are two focus knobs. One is the central one, which is the main focus knob. The second one is the diopter adjustment knob on the right eyepiece. It lets you adjust it to +/- 3, which should be plenty. The 14.8mm of eye relief will accommodate anyone’s needs, regardless of whether you’re wearing glasses or not. While we’re on the outside, we should discuss build quality. This pair of compact binoculars is built very well, from the sturdy construction, to the non-slip grip on the outside. There’s a single hinge design. This lets you make the binoculars somewhat more compact. It is also waterproof, and fog proof. You don’t have to worry about it falling in the water. However, as with any mid-range or budget-oriented pair of compact binoculars, we wouldn’t recommend testing these claims.
At the end of the day, if you want something better than the budget options, but don’t want to invest into the high-end models, this might be the right choice for you. You will get good build quality, decent optics, and an all-round well-made pair of small binoculars.
At a Glance
If the Wingspan Spectator was somewhere in the middle between the budget and the midrange, the Occer would be the middle between budget and the Spectator. This is another one of those binoculars that don’t have a well-known brand behind them, but come with a lot of features. It boasts good optical performance and a decent build quality, all in a package that doesn’t cost too much. But how much of those claims are true? Read on for our full review, and see for yourself.
To kick things off, the Occer has a 12 times magnification, with a 25mm diameter lens. 12 times will get you fairly close, without pushing the limits of image quality. The diameter lens is large enough for sufficient light. However, it isn’t too big, and you won’t get a big, bulky pair of binoculars. This combination makes for a field of view of 273 feet at 1000 yards. It isn’t the widest, but if you need high magnification, it’s a compromise you’ll have to make. It is, as you’ll see, the only compromise you’ll be making. While we’re at the internals, the optics are coated with fully multi-coated broadband coating. We’ll mention this below, and you’ll immediately see why it’s a great thing to have. The prism is a BAK4 one, ensuring plenty of clarity and contrast. The image is vivid, bright and sharp. The eyepieces have a blue FMC coating to ensure no unnecessary light enters, and you can use the compact binoculars even in suboptimal light environments.
Moving on to the outside, you’ll find that this compact pair of binoculars is built like a tank. The construction is sturdy, and the single hinge design is fast and smooth to operate. They’re made of ABS plastic, and there’s a non-slip rubber armor on the top. It makes sure they don’t slip out of your hands, even in wet conditions. There is a central focus ring, and the eyepieces are adjustable. You can even pull them down if you’re wearing glasses, effectively increasing the eye relief. This pair of small binoculars is completely waterproof, and shockproof. You don’t have to worry about dropping it, or being caught out in the rain – you can still use it afterwards.
All things considered, this is an interesting proposition. If you need more than the “regular” 10 times magnification, and want to maintain optical quality without spending too much money, it might be the ideal pair of binoculars for you. However, if you’re after something from a reputable brand, you might be better off looking elsewhere. We found these small binoculars a pleasure to use, but that might not be true for everyone.
At a Glance
Even though the primary purpose of a pair of binoculars is the outdoors, every once in a while there’s a pair that makes you want to use them elsewhere. Such is the case with the Skygenius 8×21 small binoculars. Even though they’re great for the outdoors, we found that they’re also a pleasure to use for situations such as a theater, or an opera, or even concerts. There are a couple of reasons for this, so read on and see if these are the best compact binoculars for certain situations.
To begin with, we have a fairly small 8x magnification. This won’t get you extremely close, but it will give you a wide field of view. To be more specific, you’ll get a 369 feet field of view at 1000 yards. This is excellent for both sightseeing outdoors, and visiting a concert in a hall. It isn’t, however, ideal, for things such as birdwatching, where you want to get close to your subject and aren’t that interested in what’s around it. The 21mm objective lens diameter might seem miniscule, especially when compared to the 32mm of the Spectator above. However, for the 8 times magnification, it sure does let in plenty of light, ensuring sufficient brightness and image quality.
That small lens diameter comes in handy when we’re discussing the overall binoculars’ size. They come in at 4.14 x 3.62 inches, and weigh a touch over 6 oz. You’ll find a foldable double hinge mechanism as well, which narrows them down to 2.35 x 3.62 inches, almost half of their extended size. This means you can easily put them in your pocket when you’re going to the theater. There’s a single center focus knob for both lenses, as well as a diopter adjustment knob on the right eyepiece.
Inside, you will find a BK7 roof prism, as well as fully multi-coated optics. This is something that isn’t that common on budget options such as this one, and it’s a very welcome addition. What you won’t find, however, is any kind of water or fog proofing. Even though you won’t be throwing any pair of binoculars in the water, waterproofing and fog proofing are both nice features to have. Without them, you’re limiting yourself to just the sunny days outside, and any kind of rain might mean that you’ll need to wrap your compact binoculars in something and put them in your backpack.
At the end of the day, the Skygenius 8×21 might not be the most outdoor-friendly pair of small binoculars. However, if you’re willing to trade that weather resistance for a budget oriented device that has impressive optical performance for its price, you won’t go wrong. You’ll be getting a very small pair of binoculars with fully multi-coated optics, a high-quality prism and an objective lens diameter that lets in plenty of light. What more could you ask for?
At a Glance
While we’re discussing the budget range, the Emarth 10×26 is a pair of compact binoculars that’s absolutely worth mentioning. You get a fairly lightweight and compact pair of binoculars, with plenty of magnification, and all without breaking the bank, or sacrificing where it matters. But, is it worth your money? Well, we think it is, but feel free to read on and make the decision yourself.
To begin with, we mentioned the 10 times magnification. We already discussed this, and 10 times is usually what you’re aiming for when you’re getting compact binoculars. You can get very close, and the 316 feet wide field of view at 1000 yards is completely sufficient as well. The 26mm lens lets in plenty of light, and the fact that all optics are fully multi coated makes for a clear and tack sharp image. You might be thinking that this is a budget-oriented pair of small binoculars, and there’ll be image quality loss, but you’ll be wrong. We didn’t notice any loss of sharpness near the edges, nor was the image with faded colors. There’s also a BAK4 roof prism, which might be part of the reason why the optical performance is as good as it is. We were happy to find that there’s no color fringing either, something that’s a common problem with cheaper binoculars such as this one.
Moving on to the outside, the entire construction of the small binoculars is made of magnesium. This is a rugged and sturdy material that will withstand any conditions. It’s also covered with a textured rubber armor that makes sure you have a comfortable and secure grip, even in wet conditions. Speaking of wet conditions, the binoculars are fully waterproof and fog proof. You won’t have to worry about moisture or dust entering the optics. There’s no mention of argon or nitrogen purging, but we had no issues when we moved outside, so you should be good.
You’ll find a focus knob on the center, which is the main one, as well as another one on the right eyepiece, for diopter adjustments. The eyecups can be twisted up, which makes for some generous eye relief. Even if you’re wearing glasses, you shouldn’t have any issues using these compact binoculars. There’s also a surprisingly close focus distance of just 4 feet, or 1.2M. If you’re using them for observation of insects or something similar, they should do the job just fine.
The Emarth might not be the best small binoculars at one certain thing. It is, however, an excellent overall package, paying attention to everything from build quality to optical performance and features. It is budget-oriented, but it isn’t biased towards anyone. If you want a “get it and forget it” pair of binoculars,
7. BFULL 12×50
At a Glance
At first sight, we couldn’t blame you if you’re wondering what these binoculars are doing on the list. Even just by looking at the picture, and seeing that they’re 12×50, you know they’re larger than anything else on the list. However, even with those numbers, they’re still fairly small and compact, making them a somewhat viable candidate if you want to go with an ever larger objective lens diameter, but not spend a lot of money.
As we mentioned, there’s a 12 times magnification here. This magnification will let you get extremely close to your subject. You’ll be making a compromise here, as the field of view is 286 feet at 1093 yards (87M/1000M). Also, if you don’t want to lose out on image quality, you’ll want a large lens to go with it, and there is one, a 50mm one at that. It lets in plenty of light, and ensures no loss of contrast, brightness or clarity is apparent. The whole optics are multi-coated, which isn’t as good as fully multi-coated, but it still does an excellent job of eliminating color fringing and sharpness loss. We’re talking about a budget-oriented pair of small binoculars here, so some tradeoffs must be made. The BK7 prism also isn’t as good as a BAK4 one, but it gets the job done while keeping the cost low.
Moving on to the outside, we have a rubberized construction which lets you hold the binoculars in almost any weather conditions. There’s a focus knob on the center, so you can quickly adjust the focus. It’s not that accurate when you want to make precise adjustments, so keep that in mind. On the right eyepiece is a diopter adjustment knob, with a diopter compensation of +/- 4. The binoculars are weather resistant, but we wouldn’t go as far as to call them waterproof. A splash of water here and there might not be such an issue. Anything more than that, though, and you’ll be much safer putting them in your backpack.
There are a couple of accessories that come with the compact binoculars. There’s a carrying strap, a pouch, lens caps for the glass, as well as a cleaning cloth for everything. You might not use all of them, or use them often, but the fact that they’re included is a nice gesture. When you take everything into consideration, this might not be the smallest, nor the lightest pair of binoculars out there. However, with the magnification factor, lens size, and build quality, you won’t find a more compact one, and certainly not at this price.
At a Glance
As we might’ve mentioned, the problem with cheaper binoculars, even the best compact binoculars that aren’t made by a reputable brand, is that they often sacrifice image quality in order to give you a higher magnification in a smaller package. However, with the SGODDE 8×25, we have the opposite. We have it in a fairly cheap pair of small binoculars as well, but that’s not immediately apparent. We loved the optics, and chances are you will too. Read on and see for yourself.
To begin with, these are 8×25 compact binoculars. The 8 times magnification might not be too much, but you get a 375 feet field of view at 1000 yards, which is impressive. In order not to lose out on image quality, there’s a 25mm lens. At 8 times magnification, 25mm is more than enough to let in plenty of light for the binoculars. There is a BAK4 Porro prism inside, and all optics are fully multi-coated with a broadband green film. This increases light transmittance, and when combined with the prism and large lens diameter, you get a bright, sharp and vivid image, even in suboptimal light conditions. To be honest, for a pair of compact binoculars in this price range, this is very impressive.
Moving on to the outside, there is a single-hinge mechanism that is very easy to fold and unfold. The whole body is completely rubberized for grip and durability, and it won’t skid out of your hands if the conditions are less than ideal. You’ll also find a large focus knob on the center, which is easy to use for both quick and precise adjustments. On the right eyepiece is a diopter adjustment knob which works in conjunction with the center focus knob, and lets you leave your glasses in the backpack when using the binoculars. The whole construction is IPX4 waterproof, which lets you use it in any weather conditions you want.
When you consider everything, the SGODDE 8×25 takes all the compromises other budget compact binoculars makes, and improves on them as much as possible. Combining a smaller magnification with a larger lens diameter has a great impact on image quality. The fact that everything is packed in a sturdy and weather-protected package only adds to the benefits, and the cherry on top is the price. Overall, an excellent and well-rounded pair of small binoculars.
Before we wrap up the list with another premium offering, we have one last budget-oriented pair of binoculars to discuss. Once you start reading through the specs of the Aurosports 10×25, you might be inclined to think that you’ve already seen something similar on the list – and you’d be right. However, having options can’t hurt, especially when you need to make up your mind for something that you’ll be using outdoors. Read on and see if you should spend your money on it, or skip it in favor of something else.
To begin with, we have a fairly regular 10×25 configuration. This gives you a 362 feet field of view at 1000 yards, and the lens diameter lets in plenty of light for the 10 times magnification. There isn’t any noticeable image quality loss here, which is a good thing. The optics are fully multi-coated, and there’s a BAK4 prism to ensure sharp and clear images. Add to that the green film that has been applied to the binoculars, and you have a pair of very usable low-light binoculars. Sure, they aren’t at night vision level, but they’ll do the job if the sun sets before you get home.
On the outside, you get a single focus knob at the center of a sturdy water resistant construction. Note that we’re using water resistant, and not waterproof – if you get caught out in heavy rain, you might want to put them back in your backpack. The entire thing is rubberized with a grippy, diamond pattern, so it doesn’t slip out of your hands. Overall, it’s built very well, and no corners were cut here.
At the end of the day, if you’d rather get good, quality optics, and compromise a bit on weather resistance, the Aurosports 10×25 might be a good option to consider. It covers all the basics, and comes with a few nifty accessories in the box to add to your experience. Far from the best compact binoculars, but if you’re on a budget, you should absolutely take a look at them.
At a Glance
We started things off with a well-known brand, and it’s only suitable that we end them with one as well. Bushnell, as a brand has always raised the bar in terms of performance, and (internally) they require that all their products should both outlast and outperform anything in their class. Such is the case with the Powerview 10×25, which is a somewhat high-end piece of optics but is priced like a midrange. Where, if anywhere, did Bushnell cut corners to give us such a strong contender for the best compact binoculars on the market nowadays? Actually, on a couple of places, but read on to find out.
To begin with, there’s the “regular” 10×25 configuration. Decent magnification and plenty of light – nothing we didn’t discuss earlier. However, there’s a BK7 prism, where other competitors use BAK4. You are paying for the Bushnell name, and this is where it starts to get obvious that corners were cut. That’s not to say the optical quality is bad – quite the opposite. The images are clear and vivid and with plenty of contrast. But they could’ve done better. The roof prism has fully-coated optics, which reduces color fringing and lets you see objects at a distance with ease.
On the outside, we have a non-slip rubber armor, which somewhat absorbs shock, but its main purpose is to give you a good grip when things get slippery. It does that with ease, as holding the lightweight, small binoculars was a piece of cake. You have a dual-hinge mechanism, so you can make the Powerview even more compact than it is extended. The next place where Bushnell cut some corners is the weather resistance. The Powerview isn’t waterproof, and it isn’t fog-proof. Any sign of foul weather, and you’ll be rushing to cover it. This is a bummer, as it’s an otherwise incredible piece of gear.
When you take everything into consideration, the Bushnell competes with midrange compact binoculars, but lacks a couple of things. Both the optical performance and the build quality are mediocre, with BK7 prisms in place of the much more common BAK4, and no weather resistance in sight. It is, however, a lightweight and compact piece of gear, one that you can use when it’s sunny outside, whether you want to look at birds, or just enjoy the view. However, if you want a daily driver, you might want to take a look at other alternatives, such as the Nikon Trailblazer 10×25, or the Aurosports 10×25, depending on your budget.
This guide might sound too similar to one for a regular pair of binoculars. However, as we’re discussing different sizes, there are a few key things that are different. The lens size is vastly different, the magnification factors aren’t the same, and the performance takes a hit much sooner than with a regular pair of binoculars. So, where should your money go? What type of binoculars should you get? What features and numbers should you be looking for, in order not to make a mistake? Let’s read on and find out.
Roof prism or Porro prism?
These are the two main types of compact binoculars. The roof prism type is the one where you have straight barrels, and both the eyepieces and front lenses are in one straight line. This is a major bonus with small binoculars, as the whole profile of the optics is very small. You’ll also find phase corrected roof prisms here, which have improved performance, especially when compared to a Porro prism. They might be a bit more expensive than regular ones, but they’re well worth it. Good examples of a quality roof prism pair of compact binoculars include the Nikon Trailblazer 10×25, or the Bushnell Powerview Compact, both reviewed above.
With a roof prism, you’ll also find a folding design. The most popular option is the double hinge design, where you have each barrel folding inwards against a third, central section of the body. You’ll save a lot of space by folding small binoculars this way, making them even more compact. However, if you need to use them quickly, they might be a bit tricky to open and align the barrels for your eyesight. If wearing them around your neck, you might have them bump out of position if you hit them. An alternative is the single hinge design, which even though doesn’t let you make them as compact, is quicker and easier to open. It’s also much less prone to being moved out of position.
The other alternative is a Porro prism. It doesn’t use the conventional Porro prism design, instead opting for a reverse Porro prism. Any pair of small binoculars where you have the eyepiece and front lens not in a single line is a Porro prism. In a full-size pair of binoculars, you have the lenses sitting out wider than the eyepieces. In a reverse Porro prism, the opposite applies – the eyepieces are sitting wider than the front lenses, and this is often the case with compact binoculars. Compared to a roof prism, this design is a bit chunkier and bigger, and you can’t make it quite as compact. However, optically, it is more efficient, and cheaper to build. In a simpler way, you get more performance per dollar with a Porro prism. Indeed, you can find some stunning reverse Porro prism binoculars on the market nowadays, that doesn’t cost too much.
Magnification and objective size
When you’re shopping for the best compact binoculars, you’ll find each comes with a set of numbers, such as 10×25. These numbers are for the magnification factor, and the objective lens diameter, respectively. The 10×25 example we mentioned above would have a 10 times magnification, and a 25mm objective lens. The view would be 10 times closer than what you see with the naked eye, which is fairly close, to be honest. With compact binoculars, you’ll find that if going for a budget model, high magnification factors, larger than 10x, often come with image quality loss, especially around the edges. This isn’t the case with regular binoculars, nor is the case with high-end optics. Keep in mind that if you’re working with high magnifications, you will also want a tripod for them, as even the slightest shake in your hand will be (for example) 10 times as obvious when looking through the binoculars.
You will also find zoom binoculars, which come with a number such as 7-10×25. However, when discussing compact binoculars, zoom isn’t that common. The image quality loss is significant, so you should stay away from such options.
The second number, 25 in our example, is how big the objective lens is. The lens is often the biggest part of the optic, and this is what affects the size of the binoculars the most. It also affects how much light can enter the binoculars, which directly affects optical quality and image clarity, as well as brightness. Here is where you would be making a compromise, because you don’t want to be lugging around a huge lens, but you also want the biggest quality possible. The common numbers you’ll find here with compact binoculars are 21mm or 25mm, with some models offering even higher lenses. However, anything over 26x is, honestly, too much in terms of size and weight, and comes closer to a pair of regular binoculars, instead of small binoculars.
The exit pupil is how big the focused light that hits the eye is. If you want to see it, you’ll want to hold the binoculars around 8 to 10 inches from your face and look at those small dots of light in the center. The exit pupil diameter should always be larger than your eye’s pupil. It’s directly affected by the lens diameter and the magnification. It should be larger than the eye’s pupil because otherwise, it will appear as though you’re looking through a peephole. Generally, the human eye’s pupil is around 1.5mm during daylight, and up to 8mm in the dark. Keep in mind that as your eyes age, they dilate less, making the eye pupil more important as you become older.
The exit pupil diameter with compact binoculars and binoculars, in general, is calculated by dividing the objective lens diameter by the magnification. For example, a 10×25 binocular will have an exit pupil of 2.5mm. This isn’t that big, but it’s a compromise you’d have to make with a pair of small binoculars. Even the best compact binoculars don’t have a big exit pupil diameter but try to get one as big as possible. As you start losing light during the day, you’ll start to see the benefits of a big exit pupil diameter.
Eye relief is the distance between your eye and the eyepiece. It’s also known as the focal point where the light goes through the lens. To distance the eyes properly from the eyepiece, manufacturers install eye-cups on the eyepiece. If you’re wearing glasses, this is much more important. The glasses’ lens will distance your eyes even further. If there isn’t enough eye relief, you might notice image quality dropping, and you won’t be able to achieve sharp focus. To deal with this, some manufacturers offer dioptric adjustments. Well, at least on one of the eyepieces, so you don’t have to wear your glasses. If you have a difficult prescription, you can often also find eye-cups that you can fold back. This way, you can put your eyeglass lens closer to the compact binoculars. Another solution would be adjustable eye-cups that you can twist in and out, as per your requirements.
Another factor that is affected by eye relief is the field of view. With a longer eye relief, you’ll have a smaller field of view. If you’re after small binoculars that give you both long eye relief, and a wide field of view, you should be prepared to spend quite a bit. In order to make the best possible decision, first, see how much eye relief you need. Then get what would give you the most field of view.
Glass and prism
Even though the objective lens diameter makes a difference in image quality, the glass is another big factor, along with the coatings. The generic optical glass might come with imperfections. If not polished and ground correctly, it could cause odd light bends. This makes colors look skewed, and you won’t be able to achieve sharp focusing. Distortion at the edges is another potential issue here. If you want premium, aim for either low dispersion or extra-low dispersion (ED) glass. This is made with virtually no distortion. It transmits light as it is, without bending it at all. The images that come as a result are sharper, cleaner, and have truer colors.
You may also come across something that’s advertised as “eco-glass”. This doesn’t have anything to do with quality, instead, it applies to the materials used. You won’t find lead or arsenic here. It may, or may not have any effect on image quality, but if your lens breaks, or you need to throw your compact binoculars away, you won’t be adding anything to chemical pollution.
In terms of prisms, we have three general materials. The highest quality option is a BAK4 prism or Barium Crown glass. It has a low critical angle and a high refractive index. This results in a better light transmission, with less light loss. Light loss commonly occurs when internal bubbles are trapped inside during manufacturing. The other option is BK7, which is of lower quality, often found on budget options. It has a limited number of internal imperfections. However, it’s still optical glass, so light transmission is great. There’s an easy way to find out if your small binoculars have a BAK4 or BK7 prism. Turn them around, hold them around 6 to 8” from your face, and look down the objective. Note the exit pupil. If it’s a squared-off side, it’s a BK7 prism. If it’s a true round exit pupil, you have a BAK4 prism, which gives you a better edge to edge sharpness.
In the middle, between BK7 and BAK4, we have SK15 glass. This is an atypical material which has a higher refractive index than the other options, but the dispersion is right in the middle. If you have an SK15 prism, you’ll have a very clear image, with high contrast.
When we’re discussing coatings, there are two things to mention – the lens, and the prism coating. The lens coating is a film that is applied to the lens surface. It reduces glare and reflection, makes colors more vivid, and increases contrast and light transmission. By eliminating reflections, the image is brighter and sharper. The coatings in general, provided they make a difference, are a good thing. Putting a cheap coating on a lens to make it look blue might be cool, but if it makes no difference to image quality, it’s not worth it.
There are a couple of terms to note here. You will find coated, multi-coated and fully multi-coated lenses. A coated lens has at least one lens surface, with at least one layer of coating. A multi-coated lens has multiple surfaces, and/or multiple layers of coatings to each surface. A fully multi-coated lens has all surfaces, both inside and out, coated with multiple layers. This is where you’ll find the best light transmission, as well as contrast, clarity, and colors. Last but not least, you have broadband fully multi-coated, which is rarely found in compact binoculars. This has coatings engineered for maximal efficacy across a wide spectrum of wavelengths.
Aside from lens coatings, we have prism coatings. These will increase light reflection and improve the brightness and contrast. Many manufacturers opt for basic reflective coatings. However, with high-end options, you’ll find dielectric coatings. These allow close to 100% of the light to go through the prism, resulting in a bright, high-contrast image. You will also find phase-correcting coating, but only on roof prisms. Because of how a roof prism reflects light, it gets split into two beams after it goes through the objective lens. These beams travel through the prism independently. There’s a “phase shift” because one beam will strike the eyepiece a millisecond before the other one. Once they’re combined in the eyepiece, they’re out of phase. This affects color rendition and balance. With a phase-correcting coating, the faster beam is slowed down to match the other one. This puts them back into phase, and the image is much clearer, with better colors and contrast. A regular user might not notice the difference, but a pro will easily see it. If you need to pick out an important detail at a distance, or in challenging light, this might be an issue. A Porro prism doesn’t suffer from phase shift, so this isn’t necessary with them.
Many small binoculars, especially cheaper ones, come with no weather resistance at all. Others are just waterproof, while the good ones are both water, and fog proof. If you have one that isn’t weather resistant, you might want to leave it at home if you’re going out to sea. Or if you think it might rain, for that matter. Weather resistant is a bit better in this regard. There’s often an O-ring or gasket, that keeps moisture away from the optics. Under most normal conditions, a pair of compact binoculars shouldn’t have fogging issues either.
Then, we have waterproof compact binoculars. They have O-rings that don’t let moisture inside, but they might still fog up. Depending on how good they’re made, you can even submerge some small binoculars for a specific amount of time. There’s an Ingress Protection (IP) rating for this, which might come in handy. There are others that will adhere to military standards, and rate them for fairly big depths.
Last but not least, there is fog proof of small binoculars. When the air inside the optical tubes has moisture, you have fogging. Move from a warm cabin to the cold outside conditions, and the moisture condenses. This causes the inside of the lenses to fog. Many binoculars are filled with argon or nitrogen, to prevent this. The gas is dry and is pumped inside under pressure, keeping O-rings and gaskets in place.
You might be wondering what’s the difference between argon and nitrogen. Performance-wise, there isn’t one. However, the argon molecules are larger than the nitrogen ones. Therefore, some manufacturers think that the larger molecules will have a harder time leaking. This should keep the gas inside for longer, and help maintain the fog resistance for longer. However, from a practical point of view, choose either, and you’re good to go. Remember, any fog-proof compact binoculars are waterproof, but not all waterproof binoculars are fog proof.
A few other things to mention
Above, in the buyer’s guide, we focused on the key aspects of choosing the best compact binoculars. However, that’s not to say that the factors above are the only things one should consider. There are other things to note, too. However, they aren’t nearly as important as the ones above. Things such as minimum focus distance, housing, and focusing type, and chassis material are all important, but not as much as knowing the basics. We also didn’t focus as much on rain guards, straps, tripod adapters, and harnesses, as these are all things that are a personal preference, and won’t apply for just about anyone.
At the end of the day, choosing the best compact binoculars for you isn’t that hard. The list above covers options for anyone’s pocket, and for anyone’s use case. If you went through it, but still have questions, chances are that the buyer’s guide covers the answers. There are a lot of options, and a lot of variables to consider, but at this point, you should be ready to make an informed buying decision, without worrying that you’re buying the wrong pair of compact binoculars.