Most people will often associate binoculars with birdwatchers or naturalists, who will almost certainly have a pair hanging around their neck. Still, they're not the only people who can benefit from having a pair of these optical wonders. With far reaching appeal binoculars can also be handy for stargazing, landscape and wildlife photography, travel, mountaineering, theater performances, festivals... the list goes on!
A good pair of binoculars can be a great asset on a photographic shoot, allowing you to view the landscape around you and scout out new locations for the perfect viewpoint. Binoculars allow you to assess the route ahead and make informed decisions about where to go in search of that perfect image.
Outside of photography, binoculars can enhance many experiences in life, bringing you closer to the action and allowing you to view details in the world we often miss. Having a compact pair in your bag can be excellent for holidays and live performances, meaning you will never miss out on the full experience of an event. I may be a wildlife photographer and naturalist professionally, but on holidays I have often used my binoculars to track down a hotel or even look for a free spot on the beach!
Binoculars use a combination of glass elements to enlarge a scene, in order to provide a magnified image for the user to view. The quality of the image will therefore largely be down to the ability of the glass to render details and allow the transmission of light into our eyes.
There are two main types of binocular: Porro prism and roof prism.
Obvious from their wider shape, Porro prism binoculars use an offset internal prism to magnify an image. The wider distance between the two object lenses results in excellent 3D images compared to the narrower roof prism designs. Due to the simple engineering involved, Porro prism binoculars are easy to manufacture and so offer good optical quality at low cost. A downside to the larger size is that they are far less compact than roof prism models and so nowadays they are less favoured, particularly with improved optical quality of roof prism designs.
By using a smaller type of prism than Porro types, roof prism designs allow all the optical elements within the binoculars to be aligned in the construction; this in turn allows manufacturers to produce far more compact and lightweight designs. Due to modern optical engineering, decent roof prism binoculars offer excellent image quality and are favoured by most users for their compact size and improved ergonomics. Almost all of the top brands' high-end binoculars are now based around a roof prism design.
When buying a pair of binoculars you will soon notice that each pair has a set of two numbers following their name, such as “7x32” or “8x42”. The first figure is the magnification, which indicates the number of times larger an object will appear when viewed. The second figure indicates the size of the object lens in mm; the larger it is, the brighter the images will seem.
All binoculars are designed to magnify the view we are looking at, but they come in a variety of strengths, ranging from 4x all the way to 15x. The most popular magnifications are those between 8x and 10x as they offer the best compromise between image enlargement and field of view. The reason many people pick 8x over 10x binoculars is that, when held for longer periods, shake in the hands becomes far more evident with higher magnifications.
Object lens size
Object lens size refers to the front element of a pair of binoculars and is given in mm. These come in a range of sizes from 20mm (seen on compact designs) to 50mm (on full-sized pairs). The amount of light entering a pair of binoculars is directly related to the surface area of the object lens. The diameter of the beam of light which exits the binoculars and reaches the eye is known as the exit pupil, and it's directly related to the magnification and object lens size. To find the exit pupil of a given pair of binoculars you simply divide the object lens by the magnification - so, 32 divided by 8 would give an exit pupil of 4mm. The iris of the human eye is generally dilated by 2-3mm in sunlight and 6-7mm in twilight conditions, so for general daytime use choose a pair of 10x42 or 8x42 binoculars with an exit pupil diameter of around 5mm.
Field of view
When looking at specifications of binoculars, field of view will often be expressed as either a length in metres from a distance of 1000m or in degrees. The wider the field of view in a given pair of binoculars the easier it is to locate objects in the field. The field of view is not defined solely by the magnification and object lens but is down to optical design. Higher quality pairs often will have a larger field of view due to better optical design, but often pairs with lower magnifications have larger fields of view. Those looking to use binoculars for scouting locations should look for binoculars with a large field of view; this will allow you to take in more of the scene in a single view rather than having to constantly scan along the horizon.
Modern technology and the development of new glass compounds has resulted in huge improvements in optical quality. Modern day optics can render far more natural looking images that provide an almost 3D viewing appearance, even in low-light conditions. The modern day glass elements are also coated with anti-reflective and glare-resistant coverings to once again improve the abilities of these precision-engineered optical instruments. As much as new technologies have vastly improved all binoculars, as with many things in life it's still a case of getting what you pay for when buying a pair of binoculars. High-end optics command premium prices for good reason.
Build quality and weatherproofing
As with all equipment for use the in the field, good build quality is paramount for longevity and comfort. Modern day binoculars are constructed in a range of ways and from a number of high-quality materials to produce designs that are strong and long-lasting, while at the same time light and comfortable to use.
The base materials for the construction of today's binoculars include polycarbonate resins and plastics, used for cheaper options, and magnesium alloys being used in more expensive models. The cheaper resins and plastics produce binoculars that are tough and resistant to knocks and bumps but are heavy in weight. Magnesium alloy designs have an excellent combination of strength and resistance to constant use, while also being lightweight, but this does come with a significant price increase.
Most people will, of course, want to use binoculars outdoors (unless they're just for spying on neighbours) so its worth investing in a pair that are weatherproof to guard them against the elements. Most up-to-date binoculars are environmentally sealed and will be filled with an inert gas (often nitrogen) in order to reduce internal fogging, which stops the elements misting up inside and making them useless. Some pairs offer better levels of weatherproofing, with some being constructed to even allow full submersion in water down to around a metre; if you do a lot of watersports this may be something to consider. Most binoculars will be up to day-to-day use in the field, but if you use them regularly and keep them out in all conditions, consider investing in a pair with slightly better weatherproofing. It will be money well spent!
Weight and size
Weight and size should also be a consideration when choosing a new pair of binoculars. Think about how you will be using your binoculars: how long you typically will be holding them in one period? Will you be travelling?
The problem with size and weight is that everything is a compromise. If you choose a large pair with large object lenses for the clearest images they will be heavy and a burden to carry. If you choose a compact pair with small object lenses they will be lightweight and perfect for travel, but you may soon become frustrated with the reduction in image clarity.
Size is an important factor, not only in terms of the amount of space your binoculars will take up in baggage, but also for the level of comfort they provide to the user. Large pairs that are heavy can be uncomfortable to hold if they do not fit your hands properly, and you will soon find they are far less enjoyable to use for long periods.
Weight comes with size and is not always a bad thing. After all, ultra-lightweight pairs can often feel cheap in the hand and weightier models can often feel more solid and stable in use. Weight and size will always be a compromise no matter how much you spend as larger object lenses will always require a heavier and larger build. For most people a mid-range pair of 8x32 or 8x42 binoculars are the best overall compromise, and these don’t have to break the bank.
In the above sections I mentioned a few of the characteristics that affect the ergonomics of a pair of binoculars (weight, size, materials, object lens size) but there are a few other points that are also worth considering:
Location of the focus wheel
It may seem obvious but the location of the focus wheel is of paramount importance when choosing binoculars. If the wheel is too close or far away it can be difficult to use, resulting in frustration while out in the field. The focus wheels on most binoculars are found in the centre of the body between the eyecups, and are generally made of rubberized material for grip. This allows the wheel to be turned by the index finger of either hand for simple and straightforward operation. On some compact pairs (as well as on cheaper binoculars) the focus wheel may be positioned in the centre of the body or at the same end as the object lenses; this can result in the user needing to stretch their fingers to operate it making it uncomfortable and causing hand strain.
Eyecups are an essential part of a good binocular. They make them comfortable to use for long periods and help eliminate stray light from entering the optical system via the rear optical elements. Most binoculars feature adjustable eyecups that provide a range of eye relief depths to accommodate an individual's preference. Good quality eyecups lock firmly in place and don’t move unless made to, while on some cheaper models you will find they can be knocked out of position fairly easily.
For those of us who wear glasses, make sure you purchase a pair with eyecups that can be either folded, twisted or locked down. If you're going to wear glasses when using your binoculars, try and purchase a pair with eye relief of 15mm or over to maintain a large field of view.
Most pairs of binoculars are built around a central hinge, which allows you to vary the distance between the eyecups to fit your own face. Most binoculars feature a long central hinge that connects the two optical pieces together, with space at the end to wrap your lower fingers around for extra grip. Some designs feature two smaller hinges that take up less space, which allows more room for fingers to be wrapped around for a firmer grip and comfortable hold. These types of binoculars are excellent for those with smaller hands, as well as those who want to use them for long periods of time.
More of an accessory, but still worth a mention. Most binoculars come with a material strap for supporting them around your neck. If you use your binoculars often, upgrading the strap and purchasing one separately can greatly improve comfort for extended use in the field.
Image stabilisation works by using small electromagnets to reposition the lens elements cushioning them from external vibrations. These types of binoculars are brilliant when you want to use higher magnifications, or for those with less steady hands looking for shake-free images. The inclusion of the technology does have drawbacks, though, which include added weight and the need to replace the batteries periodically. Binoculars with this technology also cost more on average, but prices continue to fall which should make them more accessible to a larger audience.
So what type of binoculars should I buy?
Best budget binoculars
If you're looking for your first pair of binoculars you may be on a tight budget, but this doesn’t mean you can’t pick up a quality pair of binoculars. If you have up to around £150, buy a pair of Porro prism binoculars that offer 8x magnification and reasonably large object lenses of 42mm or above. Having the larger object lenses will let in more light to give you a clearer image. Companies such as Opticron and Bushnell offer some great products in this range.
Best binoculars for low light
Large object lenses are a must in low-light conditions, as these will help gather as much light as possible for clear views in the twilight hours. To gain the ultimate performance pick binoculars with lower magnifications of 7x or 8x paired with 42mm or larger object lenses in a Roof prism design. Some of the top brands' 8x32 optics offer excellent low-light performance but these are expensive and will set you back well over £1000.
Best binoculars for travel
Size and weight are probably the main considerations when selecting travel binoculars, so look for a pair with smaller object lenses as this drastically reduces the size. The common sizes for pocket binoculars range from 20mm to 30mm. Pocket models featuring twin folds allow them to fold down ultra small, but in use the twin hinge system can be frustrating. For the ultimate compromise, some of the top brands offer binoculars in the £600-800 price range that feature object lenses of 30mm. These may simply be scaled down versions of their top-end optics, offering excellent clarity and performance in lightweight and compact bodies.
Best binoculars for birdwatching/nature observation
When watching wildlife you're going to be outside in a variety of conditions, so invest in a pair of binoculars with good weather sealing. If you are an avid nature watcher and thinking of investing in a scope in the future, purchase 8x magnification binoculars rather than 10x ones as they will offer a larger field of view and are easier to use when locating subjects. A few years ago 8x42 pairs were the choice among most naturalists, but 8x32’s are becoming increasingly popular due to their more compact form and lighter weight.
Best binoculars for consistent use
This isn’t what you want to hear, but if you are going to be using your binoculars often (more than once a week) it's worth spending the money and purchasing the best pair you can afford. If you enjoy nature watching or any type of activity where you use binoculars all the time, investing in a high-quality pair will reward you with brilliant views for years to come. 8x32 and 8x42 models from the top brands will set you back upwards of £1300 but you will keep them for years and be rewarded with beautifully clear, high-contrast views in all conditions, making them worth every penny. It's a case of save up, buy once, buy right and enjoy forever.
Hopefully the above information should give you all the information you need to make the right decision about what type of binoculars to buy and what features to look for. As I mentioned at the start, binoculars are exceptionally useful for more than just watching wildlife. Once you've added a pair to your kit you'll soon see the benefits they bring for a number of field applications.
About the Author
Tom Mason is an up-and-coming wildlife and nature photographer based in Hertfordshire where he frequently visits a number of local nature reserves including Rye Meads and Amwell. You can see more of his work on his blog.