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Binoculars
Choosing the right binocular can be difficult, as it is a very personal choice and only you can decide between performance and price. Ultimately, you should feel comfortable using your chosen binocular and should not be overly concerned with styling and features.

What do the figures mean?
All binoculars have a set of two figures indicating their specification (for instance 10x40).

The first figure refers to the magnification. This is typically between 7x and 10x, although specialized binoculars range higher and lower than these. The second figure describes the diameter of the large lens (called the objective) in millimetres. Generally speaking, the larger this lens is, the greater the amount of light that will be gathered and therefore, the brighter the image.

What magnification do I need?
Higher magnification can cause:
• difficulty in holding the binocular steady.
• reduction in field of view.
• loss of image brightness.

A higher magnification would generally be recommended for use in hides or for viewing at estuaries and reservoirs.

Lower magnification can provide:
• closer focussing.
• greater field of view.
• greater depth of field.

These lower magnifications are ideal if you are also using a telescope. For general use, lower magnification binoculars are recommended as they tend to give a brighter image with more depth of field. If you do not intend to use a telescope, a higher powered 10x binocular is a good compromise.

Telescopes
Telescopes have become increasingly popular among birdwatchers. By offering higher magnification, they add a new dimension to bird watching. Telescopes come in component form - the body, eyepiece and appropriate support, usually a tripod. It is important to take care when choosing your equipment.

What magnification do I need?
Telescope magnifications range from 15x to 60x. Some specialist instruments offer even higher power. If the telescope has a fixed eyepiece, 20x or 30x is normal. Most telescopes on the market today have a range of interchangeable eyepieces, so you can choose more than one. Wide-angled eyepieces of 20x to 30x are good for general use; a 40x might be useful for longer distance work.

When using higher magnification, the image brightness and field of view decrease dramatically. Any shake from the support becomes more evident. In practice, this means that the higher power eyepieces are best used in bright conditions for stationary birds.
Zoom eyepieces work well with some telescopes, usually the ones with the larger objective lens. The range is usually between 15x & 60x. But remember, with higher power, the amount of light passing through to the eye will be reduced.

Smaller telescopes have 50 or 60 mm objective lenses, and being compact, they are ideal for general work. Most manufacturers offer telescopes with larger objective lenses, between 65mm and 85 mm. These perform better in low light, but the large lens adds to the size and weight of the instrument. Due to the increased light transmission, zoom eyepieces work better with this type of telescope.

Basic guidelines
For general observation, choose a compact 60mm scope with a wide angled 20x or 22x eyepiece.

If you need higher power, choose a 30x or 40x eyepiece in addition to, but not instead of the general one.

The larger 65 mm - 85 mm telescopes are ideal for use in low light or from a fixed position such as a hide. Again the wide-angled, fixed 20x - 30x eyepieces are best, but a zoom works well with this type of telescope.

If you wear spectacles, choose an eyepiece which has a retractable eye cup, although you may still lose some field of view.

Did you know?
You can recycle your old, unwanted binoculars with the RSPB second-hand binocular scheme.
For information about the scheme please call 01767 693690, visit www.rspb.org.uk/supporting/green/donateoptics or e-mail binoenquiries@rspb.org.uk.

RSPB Optics
You can find even more binoculars, scopes and accessories from a variety of brand names at www.rspboptics.com