What to take into account
The most important criterion is comfort. The binocular must be comfortable to hold and the focusing wheel easy to reach and turn. It must also be possible to look through them without straining your eyes – you want to enjoy using them!
The first step is to decide on the following:
- how much do you want to spend?
- are size and weight important?
- what magnification and what type of binoculars do you want?
These will give you good starting points when going to a shop to make your choice.
The RSPB runs field days where you can try binoculars under field conditions. This will help you to make sure you are completely happy before purchase. The shops on reserves listed on this page keep a good range of binoculars. Contact them directly for details of products and events. You can also follow the link to see if there’s an equipment demonstration near you soon.
Alternatively, follow the link on this page to visit the RSPB online shop. Don’t forget, all sales will benefit our conservation work and help birds and wildlife!
What type of binoculars do I need?
There are two main body types:
- Porro-prisms have a ‘traditional’, stepped shape with an angled body.
- Roof-prisms are recognised by a straight-through appearance. They tend to be more compact than porro-prism binoculars and many people find them more comfortable to use. Their internal focusing helps protect them from the elements.
Choice of style is personal preference, but because of fashions, most of the high-quality binoculars today are roof-prism.
Miniature ‘compact’ binoculars are useful if size and weight are important factors. Their main disadvantage is reduced light-gathering power and field of view. They are easy to hold but you may prefer a more solid shape for steady viewing.
Rubber covering offers better protection against knocks against the body (not against the lens). Waterproof binoculars are widely available, particularly in roof-prism style. Coatings on lenses and prisms improve light transmission through the binocular and give a clearer image.
For disabled birdwatchers, the choice of binocular is dependent on the nature of the disability and personal preference. Trying out different models is particularly important. Low magnification binoculars need less refocusing and offer greater steadiness; stabilising binoculars work well but they are heavy and expensive. Specialist optical suppliers can offer personal solutions.
What magnification do I need?
Generally speaking, the lower the magnification:
- the brighter the image
- the closer the nearest focus point
- the greater the depth of field
- the wider the field of view
- the easier the binoculars are to hold.
Generally speaking, the higher the magnification:
- the less bright the image
- the narrower the depth of field, requiring more frequent focusing
- the heavier the binoculars are likely to be
- the harder they are to hold still.
- For general birdwatching, lower magnifications such as 7x or 8x are recommended, especially if you also use a telescope.
Higher magnifications (10x) are more suitable for use in hides or for viewing estuaries, reservoirs or other large, expansive areas. If you do not use a telescope and weight is not a problem, the higher 10x magnification can be a good compromise.
Zoom binoculars with variable magnification are not recommended. They rarely give as good an image across their range as single magnification binoculars and have more chance of developing faults.
What do the figures mean?
All binoculars have a set of two figures indicating their specification (for instance 8×32), sometimes followed by a letter code such as B or GA.
The first figure refers to the magnification. This is usually between 7x and 10x, although binoculars with lower or higher magnification are available. The second figure refers to the diameter of the larger lens, the objective lens, in millimetres.
Generally speaking, the larger the lens, the greater amount of light will be gathered and, therefore, the brighter the image.
The size of the binocular is governed by this second figure, not by the magnification.
B after the figure means that the binocular has rubber or push-down eye-cups, so spectacle wearers can use them with little noticeable loss of field of view (the width of the image).
GA or RA shows that the binocular is rubber-covered, offering some protection against knocks and wear.
The field of view may be quoted in degrees or figures (such as 6.5° or 140 m at 1,000 m). Roughly, 1°=17 m at distance of 1,000 m.
Do not consider the figures in isolation. An inferior 8×32 using poor glass and inadequate lens coatings may have an image less bright and sharp than a better-quality 8×32.