10x42 Binoculars

What does 10x42 mean?

The first number is the magnification: a bird 100m away looks as if it were 10m away. The second is the objective lens diameter in millimetres, the size of each front lens, which decides how much light gets in. Divide 42 by 10 and you get the exit pupil, 4.2mm, the width of the beam of light reaching your eye. That is plenty in daylight and in low light on a dull afternoon, though an 8x42 (5.25mm) or a 10x50 (5mm) looks brighter in the last half hour of dusk.

The trade-off is field of view. More magnification means a narrower slice of the scene, so most 10x42s show around 105m to 117m at 1,000m, against roughly 125m to 140m for an 8x42. The RSPB's guide to binocular terms explains the rest of the numbers on the box.

10x42 vs 8x42: which should you buy?

It depends on where you look. Both sizes weigh about the same, often within 20g in the same series.

Pick 10x if most of your watching is at range: waders on the mud, raptors over a ridge, ducks on the far bank. Pick 8x if you watch warblers in hedges and trees, or want one pair for everything; see our 8x42 binoculars. For long walks, an 8x32 saves 150g to 200g, and for stargazing the bigger 10x50 binoculars gather more light.

Compare every pair on this page

All share the same 42mm lens diameter and 4.2mm exit pupil, so the differences come down to glass, field of view, weight and warranty. Specs are from each maker's listing; prices move daily, so check the cards for today's figure.

The Hawke and GPO pairs come in two or three finishes (black, grey, green or brown) with identical optics.

What to look for in 10x42 binoculars

• ED lenses. Extra low dispersion elements cut chromatic aberration, the purple fringing round a gull against a bright sky. Almost every pair here has them; the Hawke Frontier HD X is the exception, which is why it costs less than the ED X.
• Prism coatings. Phase-corrected roof prism glass gives a sharp image with more contrast, and dielectric coatings raise light transmission, which shows on a grey winter day.
• Field of view. Wider makes it easier to find a moving bird. The Kowa BD II leads at 126m; the Celestron TrailSeeker is narrowest at 103m.
• Eye relief. Glasses wearers need around 15mm or more to see the full view. The Celestron Regal gives 20.2mm and the RSPB Sparrowhawk 17.8mm.
• Weight and build. From 610g (Viking Peregrine) to 860g (GPO Passion HD). Magnesium bodies feel solid; the polycarbonate Hawke Endurance keeps the price down.
• Weather sealing. All are waterproof and nitrogen filled or argon purged, so they won't mist inside. The Hawke Frontier models carry an IPX7 rating.

Best picks at each budget

Under £300: the Hawke Endurance ED and Bresser Pirsch ED both bring ED lenses and lifetime warranties to entry money. The Endurance focuses down to 2m, handy for butterflies; the Bresser is 70g lighter.

£300 to £400: the Viking Peregrine ED is the lightest pair here at 610g, the Celestron Regal suits glasses, and the Engage EDX has EXO Barrier coatings that shed rain and fingerprints. See more on our Viking binoculars and Celestron binoculars pages.

£400 to £500: the busiest band. The Kowa BD II has the widest view, the GPO Passion ED and Hawke Frontier ED X have tough magnesium bodies, and the RSPB HD and Harrier X come from the charity's own range. Compare whole ranges on Hawke binoculars, GPO binoculars and Kowa binoculars.

£750 plus: the RSPB HDX (660g) and Sparrowhawk ED, and the GPO Passion HD, which the Best Binocular Reviews site rated the best binocular it tested in 2019. More on RSPB binoculars. Above this sit pairs like the Swarovski NL Pure, at well over £2,000.

Where 10x42s work best

• Estuaries and the coast: picking out a dunlin from a knot across the mud is where 10x earns its keep. The RSPB reserves finder lists hides and sea walls near you.
• Moorland and hiking: scanning for grouse, hen harrier or red deer at a few hundred metres.
• Stalking and hunting: fine in daylight, though dawn and dusk favour the bigger exit pupils on our hunting binoculars page.
• Sports, safari and travel: good reach, but for a pocket choose compact binoculars.
• Astronomy: a 10x42 is a fine grab-and-go pair for the Moon and star clusters; dedicated astronomy binoculars go bigger.

How to hold 10x binoculars steady

Ten times magnification also magnifies every wobble. Tuck your elbows into your chest, rest your thumbs on your cheekbones and breathe out before you look. A fence post, wall or car roof helps, and for long sessions over water many full-size roof prism pairs have a socket in the hinge for a tripod adapter; check the listing. The Which? binoculars buying guide has more tips.

Frequently asked questions

Are 10x42 binoculars good for bird watching?

Yes, especially for wetland, coastal and upland birding where birds are far off. In thick woodland an 8x42 or 8x32 is easier, because its wider view helps you find small birds quickly.

How far can you see with a 10x42?

There is no fixed limit; they make anything look ten times closer. In practice, in good light you can pick out the markings on a duck or wader at a distance of a few hundred metres and watch deer on a far hillside.

Do they suit glasses wearers?

Most do. Twist the eyecups fully down and look for 15mm or more in the table above. Every pair on this page with a stated figure has at least 15mm.

Are 10x42s any good for stargazing?

Yes, for the Moon, the Pleiades and the Milky Way. Rest them on a wall or tripod. A 10x50 shows fainter objects, but a 10x42 is lighter to carry out to a dark site.

Is it worth paying more than £100?

For regular use, yes. Budget porro prism pairs such as the Nikon Action are bulkier and rarely fully sealed. Pairs from about £280 add ED lenses, coated prisms, proper waterproofing and long warranties.