Buying Guideoptics

Binoculars Buying Guide Australia: How to Choose a Pair

How to choose binoculars in Australia: magnification, brightness, field of view, weight, prism type, warranty and your consumer rights explained plainly.

Researched and edited by the PouchMe team Updated 19 October 2026 Every fact linked to its source

Short answer

Binoculars trade magnification, brightness, field of view (how wide an area you see) and weight against each other, so a gain in one can cost you another. Higher magnification narrows the field of view and dims the image, and in general weight rises with power. Decide where you will use them most and whether you will carry them for long periods, then choose the balance that suits.^[1],[2]

How to choose binoculars

Magnification: this is how many times larger things look. An 8x pair shows an image eight times the size the unaided eye would see. Lower magnification tends to give a wider field of view, which means more peripheral vision. Higher magnification is good for detail but narrows the view.^[1],[3]

Pocket or full-size: pocket binoculars have objective lenses of about 25 mm, against about 42 mm for full-size pairs. Pocket models often have 8 or 10 power, but their field of view is usually quite narrow.^[2],[4]

Weight and carrying: weight matters if the binoculars will hang around your neck for long periods. Weight rises with power and with angle of view, so some compromise is needed. Angle of view is the field of view stated as an angle, in degrees.^[2]

Steadiness: this is a separate limit. From about 10 power upwards, binoculars get harder and more tiring to hold steady unless they are on a mount or have image stabilisation.^[5],[6]

Brightness and lens size: the front (objective) lens sets how much light the binoculars gather, so a larger lens gives a brighter image. A larger lens also makes the binoculars heavier.^[7],[8]

Exit pupil is the bright circle you see in each eyepiece when you hold the binoculars about 30 cm from your eyes and point them at a light. To work it out, divide the objective lens diameter by the magnification. A 42 mm lens at 8 power gives 5.3 mm. A larger exit pupil gives a brighter view, which matters in dim light. For comparison, the pupil of your own eye ranges from 2–3 mm in daylight to about 7 mm in the dark.^[8],[9]

Weigh lens size against exit pupil and how you will use the binoculars, not on its own.^[1]

Roof or Porro prisms: prisms are glass blocks inside the barrels that bend the light on its way to your eye. Binoculars use one of two layouts.

Porro prisms use two glass prisms in each barrel to bend the light in a Z-shaped path. Each barrel is shaped like a dog leg to fit them, which makes the binoculars slightly bulkier.^[10]
Roof prisms give a more compact design, but they are tougher to make and inherently more expensive than Porros. They also need a costly process called phase correction to give crisp images.^[10]

At low prices, an inexpensive Porro binocular is generally better than an inexpensive roof prism binocular. A maker that put all its resources into a Porro would get a pair at least as good as a roof prism, but bulkier.^[10]

Close focus: check the closest distance at which the binoculars will focus. A short close-focus distance helps if you want to look at fine details on nearby birds, insects or plants.^[2]

Build and warranty: BirdLife Australia recommends a pair with at least a 10-year warranty that is waterproof, so it can be cleaned easily.^[6]

Whatever warranty a pair comes with, Australian Consumer Law guarantees still apply. The NSW Government says: "These guarantees apply automatically regardless of any other warranties businesses give or sell you." Check the current rules with the ACCC or your state or territory consumer authority.^[11]

BirdLife Australia also warns that cheaper models may quickly go out of alignment with no option for repair, and that their coatings may deteriorate and tinge the image pink or yellow. In its view, it is difficult to find a pair suitable for regular use that costs less than $500.^[6]

Night vision amplifies existing light such as moonlight, while thermal imaging reads the heat that objects give off. Both work differently from ordinary binoculars, so see Binoculars for Night Vision: How Night Vision and Thermal Differ for how to choose one.^[12]

Check with your state or territory authority before buying or using night-vision or thermal devices.

Common questions

What do the numbers on binoculars mean?

The first number is magnification, and an 8x pair shows an image eight times the size the unaided eye would see. The second number is the diameter of each front lens in millimetres, so a 7x42 pair has 42 mm lenses.^[1]

Can I use binoculars with glasses?

Yes, if the binoculars have good eye relief. Eye relief is how far your eye can sit from the eyepiece lens and still see the full view. A good eye relief typically ranges between 14 and 20 mm. You adjust it either by turning the eyepieces or by folding back the rubber eyecups, depending on the design. The eyepiece should also be soft so it does not scratch your lenses.^{[2],[13],[14],[15]}

What are the best binoculars to buy?

There is no single best pair. Start from what you will use them for, how long you will carry them and whether you need them in low light. Then compare magnification, lens size, weight and warranty as set out above.

Which is better, 12x50 or 10x42 binoculars?

Neither wins outright; it comes down to reach versus ease of use. The 12x50 shows more detail, because higher magnification is good for observing detail. The catch is steadiness (see the Steadiness point in 'How to choose binoculars'). Both pairs are at 10 power or above, and the higher magnification is the harder one to hold steady. For brightness in dim light, divide the lens diameter by the magnification to get the exit pupil. The 10x42 works out at 4.2 mm (42 ÷ 10) and the 12x50 at about 4.2 mm (50 ÷ 12). Both come to about 4.2 mm, so neither is clearly brighter in dim light by this measure. The 50 mm lenses mainly add weight, and Nikon gives 50 mm as the general limit for binoculars used by hand. If you will hold them by hand for long stretches, the lower magnification and smaller lens are easier to live with.^{[3],[5],[8],[9],[16],[17]}

Questions about the best magnification for birding are answered at Binoculars for Bird Watching: How to Choose in Australia. Night-vision questions are answered at Binoculars for Night Vision: How Night Vision and Thermal Differ.

Sources

How this guide was made

Drafted with AI assistance from the sources listed, then fact-checked and edited by the PouchMe team. PouchMe researches products from published information; we have not tested them ourselves.

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