Binoculars are optical instruments that bring things a meter away close to the eye, giving the user the impression that they are only a few centimeters away from the action. Thus binoculars are part of the basic equipment of hunters, gamekeepers or soldiers who observe the terrain. In the form of small opera glasses, binoculars can also make a theatre or opera evening even more impressive.
Understanding Binoculars: Magnification and Stability
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The portfolio of binoculars includes model variants for a wide variety of applications. This buying guide introduces you to the subject of binoculars and gives you an overview of designs, functions and equipment elements. Finally, we also show you in detail which factors and aspects are decisive when selecting the right binoculars for your individual needs.
This is how a classical binocular worksAs a rule, classic binoculars consist of two telescopes that lie parallel to each other. There are also binoculars with only one telescope. However, these are more likely to play a role in special tasks or occasions; especially in the private sector, this version was only able to assert itself to a limited extent. The focus is therefore on classic binoculars with two telescopes. The two telescopes are connected by a so-called bridge.
The two telescopes are identical in construction. If you observe objects, objects or people from a distance through such binoculars, light rays are reflected which hit the two objectives, i.e. the two front glasses. The reflected light rays are then bundled inside the telescopes, then corrected again by a prism system and finally guided through the eyepieces to the human eye.
These three components determine the respective functional capability and make the construct a generally usable visual display unit.
The equipment components in detail
This is a lens facing the respective object of observation through which the light or light rays pass. A maximum of five lenses are installed in one pair of binoculars. The image is then generated on an intermediate level by the coincidence of lens and light. However, it stands first of all on its head and is mirror-inverted.
The prism system
The integrated prism system is a glass body that can redirect light beams – independent of the number of reflecting surfaces -. A corresponding prism system always consists of several prisms. Its task is to turn the side-inverted and height-inverted image, which is also called the “intermediate image” or “aerial image”, around again and to put it on its feet, so to speak, from the head. In this context, there is also talk of a reversal system. Thanks to this redirection, the prism system shifts the generated image towards the eyepiece.
The most optically effective part of binoculars on the eye side is the so-called eyepieces. An eyepiece can consist of an entire lens system or of a single lens. High-quality binoculars contain up to six lenses. An eyepiece is reminiscent of a magnifying glass. You look through the eyepiece and can see the image that has already been rotated and erected by the prism system. If you focus the eyepieces, the light always runs exactly parallel through the respective eyepiece.
- 【Powerful 12x42 Binoculars, but Lightweight Enough, Weight only 1.1 pounds】 Equipped with 12x powerful magnification 42mm large objective lens and 367ft/1000yds large field of view. Capable of delivering a clear face from more than 650 feet away. 0.6 Pounds lighter than 10x50 full size binoculars.
- 【HIGH-POWERED LARGE EYEPIECE BINOCULARS】 This binoculars has 12x magnification, 25mm objective lens and wide field of view, 273ft/1000yds, letting you look farther and see wider. Coating with FMC Broadband coating and premium BAK4 prism, it ensure imaging verisimilar.
- 【18mm Large Eyepiece Binoculars, Larger Image, Clearer Details】2.25 times the image size of 12mm eyepiece (e.g. 10x25, 12x25, 10x21 binoculars), 1.28 times of 16mm eyepiece (e.g. Ordinary 10x42, 12x42 binoculars). Large eyepiece binoculars make full use of 12x magnification, deliver larger image, ensure clearer details
- 10 magnification with 25mm objective lens provides high definition without a color-changed or blurred image. The 10 magnification boasts a viewing field of 362ft at 1000 yds, so you'll be able to observe a great deal without actually adjusting their position.
- [ Professional Powerful Binoculars ] Designed with 10X power magnification, 50mm large objective lens and 367ft/1000yds large field of view good for fast moving subject, are ideal for bird watching, hunting, driving, sports events.
The most important quality features of high-quality binoculars
- Prisms and lenses are made of specially assembled, high-quality glass.
- The prisms must be optimally mirrored and worked with angular accuracy.
- High-quality binoculars are often equipped with a special multilayer coating. This ensures that you get to see color-fast and pin-sharp images.
- Prisms, lenses, and eyepieces are particularly important for functionality in their capacity as optical systems. Therefore fitting accuracy and immovability are essential criteria for the installation of these optical systems.
- For the housing, a material is selected that is both comparatively light and largely insensitive to shock.
- The two halves of the binoculars can be connected with each other by means of a bridge. The connection is considered optimal if the light beams are always parallel to each other.
- The manufacturers also pay special attention to the respective mechanics for diopter compensation and focus regulation. It is imperative to ensure that this mechanism works extremely precisely here.
What types of binoculars available?
You must distinguish between monocular and binocular lenses. Through the monocular models, you only look with one eye. This variant is basically only suitable for users who are primarily concerned with packing size and weight. However, you must be able to do without spatial vision. Instead, the spotting scope is often used for nature observation, spotting, hunting, targeted surveillance and, for example, target observation in sports.
Monocular binoculars in criticism: The relaxed view is missing
The first monocular binoculars were developed when the Porro prisms were patented in 1854. However, at no time did they become widespread. Since the 1990s the monocular glasses have been experiencing a small renaissance again. For example, several manufacturers are launching monocular binoculars on the market that are offered as a weight-saving, space-saving, and money-saving alternative. However, due to their design, these special binocular versions are only suitable for a brief glimpse of a standing object. Binoculars of this type usually offer only a comparatively small field of view and are usually sensitive to sidelight. In addition, the little relaxed perspective, which often leads to rapid fatigue, is criticized.
Binocular binoculars: There are two different basic types of binoculars
If, on the other hand, you need a classic pair of binoculars, you can go for the binoculars. Two different basic types are currently available:
- Binocular binoculars with Porro prisms: In this type, the tubes are offset from each other. The lenses are rather short and wide, although the entire construction is comparatively heavy and large. Binoculars with porro prisms are available from prices below 60 Euro.
- Binocular binoculars with roof prisms: Compared to the models with Porro prisms, these binoculars are much narrower and therefore easier to store.
The figure below shows a Porro prism binocular (left) and a roof prism binocular (right).
There is normally no general quality difference between porro prisms and roof prisms. If they are, they are nuances or details. Instead, both binoculars with Porro prisms and those with roof prisms offer individual advantages.
The main advantages of roof edge prisms for binoculars
Roof edge prisms are characterized by a modern construction method. This is precisely what allows the manufacturers to keep the construction of the binoculars incredibly slim. However, this modern production is also comparatively expensive. This expense is clearly reflected in the price. The models are generally regarded as compact and handy binocular variants. In addition, thanks to modern design, higher imaging performance can be achieved with only a small footprint.
As a rule, binoculars always work with a roof prism system consisting of at least two prisms. A prism always has a so-called roof edge. Often a reflection surface is also provided with a metallic mirror coating. The most frequently used prism system worldwide after Schmid-Pechan uses silver in many cases, for example.
With most binoculars of this type, you set the desired sharpness via the individual lenses; the focus is therefore set inside the binoculars. This also allows the production of very robust binoculars, which are also partly waterproof. This is why binoculars with roof prisms are increasingly used in the navy and shipping industry in general. However, high-quality binoculars with roof prisms are often much more expensive than binoculars with Porro prisms. However, these models offer you slightly higher image quality.
The advantages at a glance
- Compact construction
- Comparable low weight
- Simple close-up focusing
- Waterproof binoculars possible
- Dust-tight models possible
- Ideal for smaller binocular models that are more suitable for people with small hands
The essential advantages of Porro prisms in binoculars
Binoculars with porro prisms can easily be recognized by their special construction. They are flat than the variants with roof edge prisms but considerably wider. Due to this special design, the lenses of almost all models are further apart. The following rule of thumb should be observed when choosing the right binoculars:
The further away the two lenses are from each other, the more spatial vision is supported or promoted.
The prisms within a system are in principle slightly shifted or arranged at right angles. From this position, they deflect the light several times. During this process, the prisms then turn the image both from top to bottom and from right to left. Basically, the Porro principle named after Ignatz Porro functions as a reversal prism. In detail, the incident light beam is rotated by a half-cube prism by a total of 90 degrees. The light beam is then directed to a second prism, which in turn reflects the light beam again by 90 degrees. The result is a fourfold reflection. The light rays are reflected twice, resulting in the image being rotated 180 degrees.
However, the image quality – depending on the manufacturer and model variant – is sometimes worse than with binoculars with roof prisms. But there are usually no more than minor differences. And there are even exceptions: Compared to the low-cost models of binoculars with roof prisms, the low-cost variants with Porro prisms deliver at least partially better image quality. In the higher price range, however, binoculars with roof prisms are clearly ahead in terms of image quality.
The advantages at a glance
- Possible relatively cheap binocular manufacturing
- Partly offer a larger field of view
- better suitability for spectacles due to wide construction
- Wide construction promotes a spatial vision
- Especially well suited for large hands
- Favorable models with Porro prisms sometimes offer better image quality than comparable cheap binoculars with roof prisms
Tips for selecting the right binoculars for your needs
- If you are a wearer of glasses, you should buy binoculars with a specified eyepiece. Such an eyepiece ensures that a greater distance to the corresponding exit pupil is guaranteed.
- Would you like to use your binoculars more in winter? Then you should make sure that you have a large focusing wheel with thumb recesses. Thanks to such a device, you can make the adjustments with gloves and do not have to take them off every time you want to make detailed adjustments using the focusing wheel. It also minimizes the risk of your binoculars slipping out of your hand.
- The following basic rule applies: The higher the diameter of a lens, the more light can be incident. With a lens diameter of 42 millimeters, for example, you can expect good and sufficiently bright images even in really poor lighting conditions.
Mini, Kompact & Classical – The different types of binoculars
Regardless of the prism system, there are basically four different types of binoculars. The designations for the respective type often vary depending on the manufacturer. Nevertheless, the following five type designations have become generally accepted:
Mini binoculars – Light, small and handy
Binoculars of this type have lenses with a maximum size of around 26 millimeters. Many of the small and lightweight mini binoculars can be folded and therefore easily stowed in a jacket pocket for example. You hardly ever have to compromise on weight either. Most models do not even weigh 300 grams. When in use, the pocket-sized binoculars usually lie well in the hand. Many of the binoculars in this category also have a rubber coating, which further increases grip. The compact opera glasses can also be included in this group.
Some models surprise with an explicitly high image sharpness
Even though you may not necessarily be able to make high-resolution nature observations with a mini binocular, many models offer astonishing image sharpness that extends to the edges. Contrast and brightness are also good on many models. In order to optimize the observation experience, you should look for a mini binocular with a closure limit of about three meters. This allows you to observe objects in the immediate vicinity in detail and also explicitly focus on them. However, the focus of these mini binoculars is often criticized. It is important that it can be regulated really smoothly and that it always functions precisely.
Important features: Diopter compensation and multiple coating of the lens
Some mini binoculars also have diopter compensation. This is a very important feature, especially for binoculars, because it solves a problem typical for optical devices. The eyes have different refractive powers. This means that one eye sees a little sharper than the other eye. In order to compensate this, an eyepiece is often equipped with an appropriate diopter compensation. But attention: Not every mini binocular can serve with such an equipment element.
If the brightness is particularly important to you, you should also include mini binoculars in your shortlist that offer a multi-cost lens.
The field of view is often larger than expected
Often, binoculars of this type are criticized for their limited field of vision. This is undoubtedly true in individual cases, but many models have an astonishingly large field of view for their size. For example, the mini binocular Nikon Aculon A30 10X25 offers a field of view of 87 meters at 1,000 meters.
What does a field of view of 87 meters at 1,000 meters mean for binoculars?
The field of view indicates the distance from the left to the right eyepiece edge at a distance of 1,000 meters. A field of view of 87 metres at 1,000 metres means that the user can see an 87-metre-wide section of a site 1,000 metres away with binoculars.
Compact binoculars – predestined for sports and travel
Compact binoculars usually contain Porro prisms. Although the respective models are larger than the mini binoculars, they are still lighter than a classic Porro or roof-mounted binocular. This also goes hand in hand with better manageability. Thanks to their comparatively low weight and size advantage, they are always easy to transport. The lightweight compact binoculars are popular for use in sports or, for example, when traveling.
Overall, the compact binoculars are considered a practical all-purpose weapon. Typically, the respective model variants have a lens diameter of about 20 and 25 millimeters. As with all other types of binoculars, you can benefit from individual advantages here, but also have to accept certain disadvantages.
The benefits of compact binoculars:
- Because of the low weight and the handy size, it is ideally suited for easy transport in the bag
- Perfect binoculars for theatre or opera
- Ideal for magnifications at very short distances
- Very well suited for children
- Because of the close proximity of the lenses, also recommended for people with narrow faces
- Often much cheaper than the classic binocular variants
However, compact design also has some disadvantages. The user has to cut back on image quality. As a rule, this is weaker than with normal Porro and roof edge binoculars. This is simply due to the fact that there is only a little space for the mechanics in a compact housing. The individual parts must also be significantly smaller.
The lens diameter is usually less than 26 millimeters. Therefore, the field of vision is significantly restricted compared to binoculars with a lens diameter of 35 millimeters or more.
Since the lenses are also smaller, they also allow less light to pass through. This is not really a problem in daylight, but at dusk or even more so at night, compact binoculars quickly reach their performance limits.
In many cases, the exit pupils are also reduced. Therefore only little light arrives at the eye. The pupils are also dilated in low light conditions, so the image in the binoculars may appear suboptimal.
What is the exit pupil (AP) of binoculars?
This specification indicates the thickness of the light beam that exits the eyepiece on the eye side. Just like the aperture of a camera, the exit pupil is an indicator of the image brightness. Since the human pupil is not larger than about 7 millimeters, the exit pupil of binoculars should not be larger. If it’s bigger then it’s not a serious problem. A new part of the light that enters the eye through the opening is lost, so to speak unused. An exit pupil of 4 millimeters is a good average value. If you want to use your binoculars in low light conditions, you should choose a model with a value of 6 millimeters.
Some compact binoculars lack additional functions such as image stabilizers or diopter compensation.
Classical Porro binoculars – universally applicable
Porro binoculars are truly universal models that are ideal for birdwatching, safaris, excursions, and recreation in general. The classics among binoculars have lens diameters of at least 35 millimeters; often even more. These large lens diameters offer a much brighter image and higher contrast than mini binoculars and compact models.
Porro binoculars provide a spatial image with high plasticity
Due to the prism technology used, Porro binoculars produce a spatial image that also impresses with its high plasticity. This allows you to use binoculars with Porro prisms both for observations at great distances and for detailed investigations at short distances. This, of course, increases the application possibilities. Whether animal observations at a great distance, a 100 meter run in an athletics stadium or the targeted resolution of feather structures in birds – everything is possible with a Porro binocular.
Classic Porro binoculars are significantly larger and heavier than mini binoculars and the compact versions. Nevertheless, the glasses usually lie well in the hand and allow easy and comfortable handling. This comfort is enhanced by numerous additional features, including multiple coatings on all lenses, aspherical lens elements, a special macro function or targeted internal focusing.
Porro binoculars from lens sizes of 35 millimeters also convince with regard to the price/performance ratio. However, the prices vary greatly. So you can get high-quality models for just over 100 Euro. In addition, you will also find on the market a model such as the weatherproof binocular Fuji Meibo 15×80 4° for over 2,500 euros.
Classical Roof Edge Binoculars – especially suitable for professional applications
Just like the models with Porro prisms, the classic roof-mounted binoculars contain lenses with a diameter of at least 35 millimeters. However, the roof edge versions have been designed for advanced applications. This is particularly noticeable when observing nature or animals professionally. Binoculars with roof prisms not only offer you high-contrast images, excellent image sharpness, and first-class brightness values but also – depending on the manufacturer and model – present themselves regardless of the lighting conditions and weather conditions.
Discriminate images regardless of lighting conditions
This means that you can make observations with a classic roof-edge binocular even when most binoculars with Porro prisms have long since lacked sharpness and brightness due to weather conditions or lighting conditions. In binoculars of this type with a professional standard, the manufacturers exclusively use high-quality types of glass and provide the optics with a multi-layer coating.
What does remuneration mean for binoculars?
Coating is a kind of anti-reflection process, as it is also known from spectacle lenses. Thin layers are applied to the lenses; often seven layers or more. These chemicals reduce the reflections on the lens so that more light passes through the lens. The result is a clearer, higher-contrast image. When buying, consumers should make sure that the binoculars have a multicoated coating.
In addition, these binoculars offer numerous mechanical and optical functions that allow the user to completely customize each setting and adapt it to his needs.
Digital binoculars – the future has arrived
For a long time binoculars were regarded as the last bastion of truly analog technology. But already at the beginning of the 21st-century binoculars with integrated digital cameras came onto the market. These were simple webcams, which – in the same direction of observation – were attached to the housing. The Japanese manufacturers Canon, Nikon, and Fujinon finally developed binoculars with built-in image stabilization. These devices had an 8- to 18-fold magnification.
The first correct digital binoculars were launched in 2011 Sony with the models DEV-3 and DEV-5. With binoculars of this type, you can make 3D video recordings and sound recordings; in addition to numerous other functions, these models also have, for example, an electronic viewfinder and GPS function. However, you should only buy digital binoculars if there is a real need for video recordings and the like.
The image quality of the analog systems is usually better than
The digital binoculars available so far still lack good visual image quality compared to the analog models. This is mainly due to the generated resolution that the electronic viewfinders are capable of. It is not without reason, for example, that professional SLR cameras are still increasingly using optical viewfinders rather than electronic viewfinders. The imaging quality of analog systems with corresponding quality is therefore still superior to digital versions in the binocular segment as well.
However, there are also advantages. For example, if you want to watch wild boars wallowing at night, digital binoculars give you a clearly visible picture even in poor lighting conditions thanks to the built-in residual light amplifier. But for normal use, the digital versions are only conditionally recommended. They alone are much too large, bulky and – in view of the image quality – too expensive.
You should take note of it when purchasing
When comparing binoculars, the following criteria and characteristics are good guidelines for finding the right product:
- Weight and size
- field of view
- Emitter pupil size
- Glass quality
- Multi-layer coating
- Enlargement factor
The magnification factor, as well as the objective diameter, represents a very important purchase criterion.
Always select lens diameter according to the application
Common lens diameters include sizes of 20, 24, 32, 42, 50 and 56 millimeters. Which lens is the right model for you depends on the purpose for which you need the binoculars? While lenses with a diameter of 20 and 24 millimeters can actually only be used for opera binoculars, diameters of 32 and 42 millimeters are predestined for observing birds or for observing landscapes while hiking. So-called Twilight lenses with 50 or 56 millimeters are popular primarily with hunters or anglers; for recreational hikers, however, binoculars with these lens diameters are oversized.
A binocular with 8x magnification is sufficient for normal use
The magnification factor, on the other hand, provides information on how large the observed object is imaged. Experts recommend magnification factors of 7, 8 or 10. At these magnifications, the user can hold the binoculars extremely steady in his hands. This is no longer the case for values that exceed a factor of 10. For extreme magnifications, a tripod or integrated image stabilization is required.
What do numbers like 10 x 50 mean for binoculars?
From the previous sections, it is already partly clear what information is hidden behind it: the magnification factor and the size of the front lens in millimeters. A binocular with the values 8 x 25 magnifies 8 times and has a lens size of 25 millimeters. So it’s a small, compact pair of binoculars. Large binoculars have values like 10 x 42.
Care Tips: You should pay attention to this during cleaning
- If you use your binoculars only sporadically, it is best to cover the lenses with a protective cover. This keeps dust and other environmental contaminants away from the lenses.
- Clean the binocular rubber linings regularly. For cleaning, you can use classic household detergents. Put some soap or dishwashing detergent on a damp cloth and follow the contours. In this way, you also remove the dirt that has already adhered to the rubber armoring in the long term.
- Use a Lens Brush available from your local photo retailer to remove dust and dirt. Preferably use a soft brush and exert little pressure to avoid scratching the optics. If required, you can also help with a microfiber cloth.
- To remove fingerprints, it is sufficient to breathe on the objective lenses and then clean them with a light, circular wipe.
- Attention! Do not use dry paper cleaning cloths; the lenses could be scratched. Optics cleaning sets should also not be used if they contain solvents, petrol or acetone. These substances attack coatings and materials.
- Instead, use Cleaners, which has been specially developed for optical devices. Alternatively, the lens surface can also be cleaned with a little pure alcohol.