There are now many comparative guides on which binoculars to buy or how to choose a good pair. However, when picking a model from the internet, a series of technical characteristics must be considered. These features obscure you in approaching the vast world of optical equipment for the first time.
This guide is your compass through the dense jungle of information about this optical instrument. For seasoned fanatics, it might serve as a refresher, but for newcomers, it’s your one-stop shop for everything you need to know about binoculars.
What Are Binoculars for?
The fundamental question is precisely this: what do you need binoculars for? The answer will determine which magnification and lens diameter is right for you. When looking for binoculars, the first thing you happen to find is a combination of numbers such as 10 × 50, 10 × 25, 8 × 42, and so on.
The first of these two digits indicates the number of magnifications: 10x, 8x, etc. It means that objects observed from a distance will appear to you from ten or eight (or other numbers) times enlarged. The second digit, the one after the “x”, indicates the diameter of the objective lenses (those furthest from the eye, so to speak) expressed in millimeters.
These are two important factors combined together. They can give you an idea at a glance of how bright the image returned by the binoculars will be, how the field of view is wide, and how heavy and bulky the instrument will be. Different uses correspond to different magnification / objective combinations.
Let’s try to summarize most of them in a table:
| Where to be used | Magnification | Lens Diameter |
| Versatile | 10 | 50 |
| Pocket-sized | 8-10 | 20-25 |
| Bird watching and hunting | 8 | 42 |
| Excursions | 7-8 | 30-42 |
| Astronomy | 10 and above | 50 and over |
| Maritime | 7 | 50 |
We will focus on brightness, the field of view, and other details shortly.
Materials and Treatments
To assess the overall image quality delivered by binoculars, another crucial factor is the composition of the optical components, specifically the lenses and prisms, as well as any surface treatments they have undergone. The quality of materials used in these optical groups, along with the surface treatments, plays a significant role in the clarity and performance of the binoculars.
Prisms
The optical system of binoculars is not limited to the objective lenses and eyepiece (the smaller lenses and closer to the eye). Inside the binoculars, there are glass prisms. They serve to overturn the image through a series of refractions so that it reaches the eye of the observer straight and not upside down.
Another relevant categorization for binoculars is precisely the type of prisms it mounts. Essentially two types: Porro prisms (from the name of the engineer who invented them) and roof prisms (so-called for their shape). The two types of prisms differ in shape and the number of refractions they perform.
Porro prisms perform less refractions but are bulkier. You can be sure that any binoculars with objective and non-aligned eyepieces mount Porro prisms. While roof prisms do some more refraction but are more compact. You can find them in all binoculars with aligned objectives and eyepiece.
One of the key challenges for any optical instrument is light dispersion. Each time light passes through a surface, even transparent materials like glass, a percentage is reflected, reducing the brightness of the image with every refraction. To mitigate this issue, manufacturers use specialized construction materials and surface treatments.
Glass
From the point of view of materials, the prisms are made of glass. But it is important to know exactly what glass is. There are primarily two types that may interest you:
- BAK-7: borosilicate glass, better known by its trade name (Pyrex), also used in optics for its excellent qualities of transparency and strength
- BAK-4: Crown-barium glass, with a better refractive index and dispersion
Both are high-quality optical glasses, but they fall into different price ranges, with BaK-7 being more affordable. The key difference lies in their refractive properties. In binoculars, using BaK-4 glass for the prisms helps to nearly eliminate brightness loss, a phenomenon that BaK-7 glass cannot counter as effectively.
Treatments
But glass isn’t the only factor when it comes to minimizing light loss. There are anti-reflective treatments that can be applied to all optical surfaces of binoculars, both lenses and prisms. The effectiveness of these treatments increases with the number of layers applied. And the more surfaces are treated, the greater the effect. This is also a feature that allows you to identify the construction quality of binoculars.
The words to pay attention to are the following:
- Coated: only one anti-reflective layer has been applied, usually only to the lenses
- Fully coated: all surfaces have been treated with an anti-reflective layer
- Multi-coated: some of the surfaces, usually the lenses, have been treated with multiple anti-reflective layers
- Fully multi-coated: all surfaces have been treated with multiple anti-reflective layers
It’s important to discuss roof prisms separately. Complex construction in binoculars can lead to a loss of image resolution. However, a treatment known as phase correction is applied to the surfaces of the prisms to mitigate this effect and restore resolution.
Other Technical Features
So far, we’ve covered the most significant technical characteristics that can help guide your choice of binoculars. However, these factors alone aren’t sufficient to fully assess the quality of the binoculars you’re considering. While we don’t aim to be completely exhaustive, we also want to highlight additional technical details that may be worth considering.
Exit Pupil
Also called the brightness index, the exit pupil is a measurement expressed in millimeters. It is the result of the ratio between the diameter of the objective and the number of Outgoing pupil binoculars magnifications. The exit pupil also represents the diameter of the light beam exiting the binoculars.
The exit pupil can be observed by looking at the binoculars from a certain distance from the side of the eyepieces: it is possible to see two luminous dots exiting from the eyepieces themselves. These two dots are the exit pupil and from its observation. You can deduce how high the light transmission is inside the binoculars. The larger the diameter of the exit pupil, the more light passes through the binoculars.
Field of View
Field of view (or visual) means the extension of the area observable through binoculars. You can find it expressed in two ways:
- In meters: you will find the number of meters observable from a distance of one kilometer (for example 114 meters from 1000 meters)
- In degrees: find the viewing angle offered by the binoculars expressed in degrees (e.g.: 6.5 °)
The extension of the visual field depends on several factors, especially magnification. The magnification corresponds to a narrower field of view. In some cases, you will hear about “wide-angle binoculars”. This means that the instrument in question has a field of view of 6 ° or more (105 meters).
For Those Who Wear Glasses
Good quality binoculars do not neglect you if you need glasses. In many models, there is a specific wheel for dioptric adjustment, which allows you to customize the binoculars precisely to your diopters. Most binoculars, whether or not they have dioptric adjustment, also have soft rubber eyepiece cups, which can be removed to adjust the distance between the eye and the eyepiece. This allows you to use your binoculars even when wearing glasses.
Focus
It seems trivial, but the focus is not necessarily the same in all binoculars. There are at least three different systems:
- Fixed focus: Some binoculars don’t have focus adjustment at all
- Central focusing: the most widespread, occurs through a wheel placed between the two tubes
- Individual focus: provides separate focus for each of the two tubes
So don’t assume that the focus is there in the first place, and check that it is the way you want it second!
Filling
If you are a hunter, bird watcher, or hiker of a certain caliber, you may also be interested in knowing what your binoculars are filled with. Yes, because not all binoculars are filled with air only! Any binoculars are worth, at least waterproof to prevent water or dust from entering the tubes. However, the best models are also filled with gas (usually nitrogen gas) to prevent the formation of fogging on the inside of the lenses.
For Fixed Supports
Another important detail to consider is the ability to mount binoculars on a tripod or other fixed support, such as a car window arm. This feature is particularly significant if you plan to use your binoculars primarily for observation from a stationary position, such as for astronomical or nautical viewing.
Not all binoculars are factory-fitted with a tripod mount. However, it is often available as an optional tool that can be purchased separately.
The Great Decision Maker: Price
But let’s get to what for many is the one and only decisive factor: the cost. Obviously, you pay for quality and great technological sophistication. We can summarize what affects the price of binoculars:
- Prisms: Roof prisms normally cost more than Porro prisms
- Glass: BaK-4 glass prisms usually cost more than BaK-7 glass prisms
- Treatments: the greater the number of anti-reflective treatments, the higher the price
- Objective diameter: all other specifications being equal, the larger the objective, the higher the cost
- Protective casing: A good non-slip soft rubber coating, which also protects against impacts, affects the cost of the binoculars
Depending on the combination of the above features, your binoculars will be placed in one of the following price ranges:
- Binoculars for kids: around $50
- Very low range: under $100
- Low range: from $100 to $300
- Medium range: from $300.00 to $900.00
- High range: from $900.00 to $2,000.00
- Top of the range: $2000 and more
Conclusion: Which Binoculars to Buy
Whether you’re a nature enthusiast, sports fan, or concertgoer, the right pair of binoculars can heighten your experiences. With a clear sense of your preferences and the technical aspects of binoculars, you can make your final decision. Trust your instincts and choose the binoculars that resonate with your needs and expectations.
We offer a selection of general-purpose binoculars here: these models can be ideal for multiple uses and will satisfy you if you do not want to use them professionally.
Let’s explore our recommendation of the top 3 best binoculars…
1. Nikon Sportstar EX 10 × 25 DCF: The Go-Anywhere Pair of Binoculars!
In the first position, we recommend the Nikon Sportstar EX 10 × 25. The advantages of this pair of binoculars are: water resistance (to a 5 min immersion underwater), a pair that is light and compact (280 grams), and a reasonable price. This model is perfect for beginners or for observing nature thanks to its 10x magnification.
Its advantages are:
- A water resistance: 5 min immersion underwater.
- Light and compact: 280 grams.
- A reasonable price.
- Perfect for beginners or for observing nature thanks to its 10x magnification.
2. Athlon Midas 8 x 42 ED: Professional Quality at an Affordable Price
In the second position, we offer you the Athlon 113004 Midas 8 x 42 ED Binoculars. This pair of binoculars arrives in the top ranking of the NYTimes comparison. It is very robust in all weather and weather conditions, reliable and fluid in its use, and is even suitable for professional use.
Here are some of its advantages:
- Robust and suitable in all weather conditions.
- Reliable and fluid in its use.
- Recommend for both casual and professional use.
- Excellent quality.
3. Olympus Binocular 10 × 50 DPS-1: Good Mid-Range Compromise
Our last choice is the Olympus Binocular 10 × 50 DPS-1 -Black. This pair of binoculars allows you far vision with good brightness and a suitable weight (850 grams). The strong points are: the UV filter to protect your eyes during your long hours of observation and a rubber coating for a better grip. The Olympus Binocular 10 × 50 DPS-1 has several advantages rarely found in this price range.
Some features we liked:
- A decent price for the good quality.
- A far vision with good light.
- A suitable weight: 850 grams.
- A UV filter protects your eyes during your long hours of observation.
- A rubber coating for a better grip.
We hope this guide has helped enhance your knowledge about the essential factors in selecting and evaluating binoculars. If you have any further questions or need additional information, please feel free to leave your inquiries in the comment section below. We are here to assist you with any information you may need.