I've had a fascination with compact binoculars most of my life. To be sure, I own and use everything in terms of binocular size from the smallest to the largest giant binoculars, but compacts have always appealed to me. Just something about being able to take a binocular with you, wherever you go and not have it get in the way. Compact binoculars fit my on the go lifestyle, perfectly. Whether I am bicycling, cross country skiing, canoeing, hiking or just shopping or out for an evening walk, the small size of a compact binocular makes it my constant companion. As a binocular expert and user for over for over forty years, though, I can tell you that compact binoculars have their plusses and minuses, just like any other binocular. They may or may not be the perfect binocular for you.

In general, compact binoculars will not offer the resolution (ability to distinguish very fine detail) as their larger siblings, simply because smaller binocular objectives (front lenses) cannot offer the resolution or performance of larger objective lenses. This is simply a law of optics regarding lens size and the ability to separate fine detail. In other words, a compact binocular will not appear quite as sharp and crisp as its equivalent in a larger binocular. Keep in mind, however, that we are talking in terms of all else being equal, comparing a compact binocular with the same brand and model in a larger version. When we begin to compare different models and sizes at different prices, we also have to account for lens quality. Lens quality can be just as important as lens size when it comes to performance. In fact, a premium (and expensive) compact binocular with high grade, perfectly ground and polished lenses can easily outperform a cheap full size binocular. We have to compare apples to apples, here.

A more significant shortcoming of compact binoculars, no matter what the quality, is eye fatigue, especially over long observing sessions. Smaller objective lenses on compact binoculars produce smaller exit pupils - the beam of light that exits the eyepiece and enters your eye. As a result, you must be more precise when centering the eyepieces over your eyes. On some compacts, even some premium compacts, being off just a little when centering the binocular over your eyes will produce detectable eye strain. For this same reason, it is also very important on a compact binocular to set the interpupillary adjustment (the width between the barrels to fit your eyes), very carefully. Opening the binocular too wide or not wide enough produces the same problem of your eyes not being centered, correctly, over the eyepieces and eye strain will result. Experience using a binocular will go a long way to minimize this problem, but I still use and recommend a full size binocular when it comes time to use a binocular for many hours a day. Compact binoculars are just not suited for long, hard observing sessions. Compact binoculars are at their best for more casual work.

One of the most common criticisms of compact binoculars is lower image brightness, for the same reason as lower resolution - smaller front lenses. While it is true that smaller lenses do not take in as much light as larger front lenses, this image brightness issue is very much over emphasized with compact binoculars. It gets repeated so often perhaps because image brightness is the easiest binocular concept to visualize and explain. However, it is a mistake to automatically dismiss a compact binocular as not being bright. In my actual experience, out in the field, in side by side tests with larger binoculars, a premium compact binocular can hold its own with a larger binocular in terms of brightness until it is nearly dark enough to need the lights of your car. That's enough image brightness for nearly any daytime use. Unless you really need a binocular for very low light conditions, it is a mistake to overlook a compact binocular on the basis of image brightness.

Small size and lightweight are the main reasons for buying a compact binocular, but these same things work against you when trying to hold a binocular steady. In full size binoculars, I generally recommend a magnification (first binocular number) of no more than 10 for the sake of image steadiness. A compact binocular in 10x is even harder to steady and use than full size 10x binocular because of its lighter weight. I still own and use 10x compact binoculars and prefer a 10x in a compact binocular for some applications, but image steadiness can be a problem for me with my 10x compacts. I often resort to bracing my 10x compacts against a tree or other impromptu support to get the steadiness I need. That's why I also own and use 8x compact binoculars. An 8x compact binocular is noticeably easier to steady than a 10x and the wider field of view of an 8x also makes it easier to get that elusive bird in the binocular field of view. My recommendation, therefore, is an 8x in a compact binocular for all around use, especially if this is your first compact binocular or you are new to binoculars, altogether.

Yes, less is more when it comes to magnification on the best compact binocular. Many beginners are lured into going more than 10x on a compact binocular, but that is nearly always a mistake. I do not recommend more than 10x (first binocular number) in a compact or even a full-size binocular unless you plan to use the binocular on a tripod, but be advised that very few compact binoculars are tripod adaptable. Besides, what's the point of carrying a compact binocular if you have to carry a tripod to use it, effectively? For the same reason (and a great many more, besides), stay away from zoom compact binoculars, altogether. Compact zoom binoculars are all but unusable at higher magnifications and, like all zoom binoculars, prone to some severe optical and mechanical problems. I never recommend any zoom binocular for any serious use.

When you need a binocular, any binocular is better than no binocular. That's the beauty of compact binoculars - you are much more likely to take a compact binocular with you because of a compact binoculars smaller size. The very finest and most expensive binocular in the world won't do you any good if you left it at home because you didn't want to carry the size and the weight. Indeed, I've add more birds to my life long bird list with compact binoculars than my best full size, dedicated birding binoculars. Why? Bird's are notorious for making appearing at unexpected times and in unexpected places (they don't read the field guides) and the small size of a compact binocular allows it to be a constant companion in my purse. A compact binocular is always there when I need it. The small size and light weight of a compact binocular also makes a compact binocular especially useful for folks like photographers, hikers and hunters who are carrying a lot of other gear. These folks still need a binocular, but adding a full size binocular to an already heavy load can be the straw that breaks the camel's back. Time for a compact binocular.

What compact binoculars lack in size, they sometimes make up in terms of optical correction, especially premium compact binoculars. Smaller lenses are easier and less expensive to produce to high optical standards than larger lenses. As a result, premium compact binoculars are nearly always better than their already excellent, but larger, premium counterparts in terms of edge sharpness and freedom from barrel distortion, flaring and coma. Some of the very finest binoculars I have tested in terms of optical correction have been premium compact binoculars by Leica, Swarovski, Zeiss and Nikon. If you are picky about optical correction and willing to forgo the optical advantages of larger objective lenses, a premium compact binocular may be your best choice.

Another plus for compact binoculars is a lower relative price. You can buy the very best compact binoculars for half or even a third the price of its larger, full size premium counterpart. Going compact in a binocular can bring that expensive European or Japanese brand of binocular into your price range. Personally, I'd rather have the very best quality compact than an equally priced, but average quality, larger binocular. That's me, though - I know and understand how to work around the limitations of a compact binocular. If you are a beginner to binoculars, I still recommend a full size binocular as a first binocular - it's important to get all the help you can in terms of performance. Add a compact as your second binocular.

Just as in full size binoculars, compact binoculars come in two basic prism types - compact porro binoculars and roof prism - and these prism types affect the body shape and, therefore, the handling qualities of the binocular. Again, there are plusses and minuses to each design.

If you wear eyeglasses, be sure to check eye relief in the compact binocular specifications. Eye relief is the distance your eyes can be from the binocular eyepieces and still see a full field of view. It is a critical spec for us eyeglasses wearers, because eyeglasses don't allow us to get our eyes close to the eyepieces as folks who don't wear eyeglasses. Sure, you can always take your glasses off and put them in a pocket or such, but that really defeats the idea of carrying a compact binocular in the first place. We carry a compact for convenience, after all.

In general, it is harder to find a compact binocular with suitable eye relief than it is to find a full size binocular with suitable eye relief for use with glasses. Why? The smaller bodies and eyepiece housings on compact binoculars do not offer room for the larger, longer eye relief eyepiece designs found on larger binoculars with their larger housings. As a result, you need to shop more carefully for a compact binocular with enough eye relief to use with glasses. You will need at least 14mm or 15mm of eye relief to see enough of the field of view when wearing your glasses to be useful, though this actual amount can vary from person to person. In a pinch, I can get by with as little as 13mm, but larger folks usually need at least 15mm and a few people will need even more, especially if they are using eyeglasses with thick glass lenses.

Contrary to what some people have been told and taught, the size of the front lens does not affect the field of view - the width of landscape you see when you look through a binocular. Field of view is a matter of magnification and eyepiece design, not size of the front lens. A compact binocular can have the same general field of view as its larger sibling with larger front lenses. True, you rarely find a " wide angle " compact binocular, since the small eyepiece housings on compact binoculars do not allow for more sophisticated eyepiece designs, but you can get plenty when it comes to field of view in a compact binocular. Checks the specs if in doubt. Field of view is not a reason to reject a compact binocular.

If you plan to use your compact binocular in cold or wet weather or any other extremes in climate, be sure to get a model advertised as waterproof. Waterproofing not only protects against moisture, it also means better seals against dirt and dust and changes of temperature than a binocular that is not waterproof. Note that it must say the word waterproof to qualify as waterproof compact binoculars, not weatherproof, rain proof, climate proof or other label. A binocular that is waterproof will always list this feature in the description and/or the specifications when present. The good news is that nearly all compact binoculars over $100 and many under $100 have this feature.

A properly designed compact binocular should allow you to focus the binocular with one finger and, if you plan to use your binocular outdoors in cold or extreme weather conditions, you will also need a compact binocular that offers a large and easily turned focusing knob. Compact binoculars with tiny focusing knobs are all but impossible to focus while wearing gloves. Those dainty compact binoculars with a petite focusing knob may work great at the opera or theater, but they are not suitable for use under extreme climate conditions.

Armoring protects the binocular from scratches and makes it quieter when it strikes an object (important when around wildlife). Armoring also makes a binocular more comfortable to hold in hot or cold weather and armoring can also help you get a better grip on compact binoculars. Armoring does not, however, make a binocular waterproof. That's a matter of internal seals, not an outer covering.