An Introduction to Binoculars

Our Guide to Binoculars

When shopping for a pair of binoculars, it’s easy to get overwhelmed by all the choices available. Even the numbers, which are intended to be helpful, can be confusing; particularly for beginners. If you’ve ever wondered about whether the bigger binoculars are better, what the numbers mean or what is the difference you are getting for the price, then we can help.

Of course, the short answer is that all of the numbers and shapes mean something. Read through the blog post below for helpful information to keep in mind when looking for the right binoculars for the job.


Words of Advice

It is always worth noting that each person will have a preference with binoculars. So what is right for 1 person may not be right for another person. Never buy binoculars without trying them first otherwise they may not be the right ones for you!

If you need more advice or help then feel free to pop in store and we’ll always help you find your perfect pair of binoculars! We have the largest range in the area and cover some top brands such as Opticron, Hawke and are one of the few authorized Swarovski dealers!


The Numbers Around The ‘X’

When looking at binoculars, you’ll see numbers separated by an ‘X’. Understanding these numbers are key to finding the correct binoculars for you. So what does 10×42 mean? Well, the first number (10) refers to magnification or power. It represents the number of times an object appears larger than normal. Most binoculars have a magnification from 6 to 12. But 8 and 10 times are often the sweet spots.

When looking through an 8x magnification binocular, an image will appear 8 times closer than it would when viewed with the bare eye. Or in other words, an object 8 miles away would appear 1 mile away. Magnification above 10 to 12 power is less common because the increased power causes the binoculars to become bulky and therefore become difficult to hold still and maintain a clear image without shaking. To counter this, you can use a tripod/monopod. So if you’re definitely after a high magnification pair of binoculars don’t be put off as you can use a tripod or monopod. But for most people, 8 or 10 times is perfect for zoom and reducing shake.

The second number in the 10×42 designation refers to the objective lens. This number represents the diameter of the large front lens in millimeters. The larger the size of the objective lens, the more light that enters the binoculars and therefore the brighter the image. This is good for difficult situations or for when you require the binoculars in low light. We often say that the best time to test binoculars is on a grey and cloudy day as the conditions aren’t perfect and you are likely to see a significant difference in brightness and overall quality.


Price Range

There can be a huge range in price between apparently similar pairs of binoculars! At J&A Cameras, we sell binoculars from £30 to almost £2000. The main reasons for such a large price range are the quality of the optics, the types of coatings applied to the lenses, and other features that might be added, such as the housing material. Additionally, the prism type can be (and often is) a factor in determining the price.



The majority of binoculars use a center focus system. The main focus wheel is set on the bridge between the two oculars and moves them symmetrically. With center focusing, many manufacturers will have a dioptric adjustment dial on one of the eyepieces to fine-tune the focus to match individual optical prescriptions. The dioptric correction amount is decided by each manufacturer, usually by model, and can be on the left or right eye, or both. Certain models have the dioptric correction integrated into the center focusing mechanism.


The Eye Relief

The distance behind the eyepiece at which the entire field of view is visible is called the eye relief. If it is very short, say 5 to 10mm, then a person wearing eyeglasses may not be able to get close enough to see the whole field of view because the glasses create a barrier. Most binoculars will have an eye relief of 10 to 20mm and will have fold-down rubber eyecups to accommodate for glasses. In general, the eyecups are raised when glasses are not being worn and closed when the glasses are on.



Most binocular manufacturers coat their optics to some degree with light-enhancing chemical formulas, but it is important to choose binoculars that are fully multi-coated for optimum light transmission. If light is allowed to go through totally uncoated optics, up to 50% of that light scatters and never reaches your eye! There are terms generally used by manufacturers to let the consumer know just how coated their optics are:

  • Coated Optics: This is the lowest grade of coating that can be found on binoculars. This means that at least one surface is coated with a single layer of a manufacturer’s own recipe for light-enhancement. The most commonly coated lens, of course, is the objective lens.
  • Fully Coated: All lenses and prisms should be single-coated. This will increase light transmission from less than 50% to about 80% if all surfaces are coated.
  • Multi-Coated: At least one surface is coated with more than one layer, and the rest of the surfaces are generally single coated.
  • Fully Multi-Coated: This is the best you are going to get in regards to coatings. This term usually means that all surfaces are multi-coated. If all surfaces are multi-coated, light transmission increases to 90-95%.


Glass Types

Binoculars have many types of glass. The most commonly stated type is ‘ED glass’. This means that the glass has a low dispersion, also referred to as colour fringing, which helps to minimize the problems caused by chromatic aberration. This means that objects have minimal amounts of a coloured outline.





You may have noticed that some binoculars look very slim while others look chunkier.

This is because of the physical appearance and size of a binocular are determined by the type of prism it uses. Prisms are used to correct the orientation of the view horizontally and vertically so the scene looks natural; without a prism, binoculars would make things look upside down and flopped. There are two principal types of prisms: roof and Porro. The glass elements in a roof prism are in line with one another, making roof-prism binoculars more streamlined and easier to hold. Porro prisms have the glass elements offset from one another and can provide greater depth of field and a wider field of view compared to similar roof prism models. This is accomplished by folding the light path, which shortens the length, spreading the objectives farther apart.



Final Words

That’s the basics covered for assisting you in finding your perfect pair of binoculars.

Feel free to come in store and ask any member of staff for more details and we will show you our huge range of binoculars along with advising you on the best pair for you.

We have a range of our stock on the website but are constantly updating with more, so take a look now! Click here!

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