How Are Binoculars Rated, Binoculars Buying Guide

If you are new to binoculars and how binoculars work, you need to learn what the numbers stand for, what the different features are, and how all this sets the different binoculars apart. Here are the basics about binoculars explained and how are binoculars rated. When you need to choose a particular pair of binoculars, you need to check their features and specifications and compare them with similar models. This will help you choose the most suitable binoculars for you.

Binoculars Buying Guide – How Are Binoculars Rated

The “perfect binoculars” do not exist. When choosing the best binoculars for nature or bird watching you have to be willing to compromise. You need to set priorities and evaluate features that are less important to you.

  • Be clear about binocular ratings and specifications
  • Know what amount you are willing to spend on binoculars

Different Brands of Binoculars

There are a lot of popular binocular brands like Swarovski, Leica, Zeiss, Celestron, Nokia, Vortex, Nikon, Wingspan, and so on. With price tags from affordable to expensive, there is a slew of models available featuring various kinds of lens coating, different optical glass types, and ergonomic properties that make the binoculars lightweight, portable, and functionally efficient.

If you’re going to choose one of the top models from these brands, be ready to spend anything between $2000 and $3000. Many people wonder whether binoculars have to be so expensive when there are models for a lot less money. However, if you have used such premium binoculars for a while and have been able to enjoy this incredible viewing comfort, then you know the difference.

Optics makers have over the years stepped up product design and released better quality models in the market that are ergonomically friendly and functionally competent. Generally, whatever is the price range or brand, any good binoculars come equipped with a standard set of features that reflect high quality and reliability. These include lightweight, compact binoculars and completely waterproof binoculars, roof-prism design equipped with top-quality, close-focus optics technology, excellent view, eye-relief, and adjustable twisting eyecups.

So, what aspects you should look for when buying binoculars. Factors like price, brand, magnification, lens diameter, close focus, and ergonomics, are important considerations as to how are binoculars rated.

While you probably have to consider a budget for your purchase, avoid buying cheap binoculars. The optics won’t be good and it will be frustrating using them. Good glass with good coating makes a big difference in optical performance. A high price tag for binoculars from a reputable manufacturer is generally a guarantee that the product is durable and functionally competent.


One essential characteristic is the magnification of the binoculars. Handheld binoculars are available in a variety of magnification options of 12x, 10x, or 8x and sometimes 7x.

The most popular ones are by far the models with 8x magnification and the binoculars with 10x magnification.

Additionally, the most suitable magnification also depends on your specific requirements. For example, if you’re planning for long-distance observations and viewing features in more detail, then 10x is a more appropriate magnification.

Objective Lens Size & Diameter

Another important consideration when purchasing binoculars it the Aperture, the diameter of the objective lens. The diameter should essentially be 5 times the magnification for a brilliant image. The reading of the lens size is a crucial metric and a pivotal specification of bird-watching binoculars. It is usually expressed in millimeters of the objective lens with measurements for the front lens on the far side. So, a typical 7x size, 35s binocular has a lens size of 35mm, 8×42, 42mm respectively.

Twilight factor

The objective lens diameter directly affects the instrument’s Twilight performance. The larger the lens is the more light it can gather, thus offering a brighter image. However, the twilight number is also in proportion to the magnification, a larger magnification means less brightness.

The number is the square root out of the product of magnification by the objective size in millimeters.
TF=√M Do

Typically the value is between 5 to 25. The larger it is, the brighter the image appears and the better the resolution.

If you intend to view birds in low light conditions like in dark woods, during dusk, or at dawn then the recommended lens size is 50mm for a 10x magnification and 40mm for an 8x binocular. Smaller apertures are not suitable observations in low light.

Close Focus

The rating ‘close focus’ refers to close-range focusing. That is the nearest distance an object may be away from the binoculars and can still be sharply focused on.   If you need to observe insects or other objects of interest at a close range, then this is another important feature to consider.

Really good bird-watching binoculars have a close focus range from as low as around 6 feet. However, there is a trade-off.  The minimum close focus distance increases with higher magnification.

Safety & Ergonomics

Good binoculars from popular brands will usually have ergonomic features infused into the design to promote comfortable usage and convenience. When choosing a particular model, make sure it is compact and test it to ensure it feels good and light in your hands.

Find out what glass is used for prisms and lenses, check for smooth and easy focusing, consider magnification, eye relief, and exit pupil.  Eye relief is a vital consideration especially for users who wear eyeglasses.

Manufacturer Amenities

With the growing trend of manufacturer support for conservation programs, many makers offer a plethora of amenities and perks to improve customer loyalty. These include service warranty offers for binoculars, funding or support for nature or birding expeditions, and research initiatives. It’s a good idea to choose a binocular from the top brand that gives back to the community as part of social responsibility and corporate sustainability. This also ensures your chosen product is high quality and reliable having been crafted by a reputable, optics maker.

So How To Choose The Best Binoculars

Picking out the best binoculars is not simple; there are a number of factors that must be considered in order to make an informed decision. If you’re going to choose a particular brand that’s popular and trending, then make sure it’s best suited to your personal preferences.

With Optics, there is a wide array of features to pay heed to, including price range, the lens, optimal magnification, close focus, etc. If you’re just going to purchase an expensive binocular because you like its design and fancy new features, it might not be the best deal.

You don’t have to be a professional or an expert to select the best binoculars for birding or nature observations, but knowing how are binoculars rated and understanding these ratings will help you to find the right one.