What the best binoculars have
- A magnification of 8x to 10x. Experts say that 8x is more than adequate for birding and other pursuits. Those with a steady hand may prefer a magnification of 10x, but if your hands shake at all -- which is normal for most people -- this degree of magnification may create a blurry image.
- A wide field of view. The experts at the Audubon Society recommend that birding binoculars should have a field of view of at least 341 feet at 1,000 yards. Having a wide field of view is especially important for beginning birdwatchers because it makes it easier to track birds in flight without scanning back and forth. Hunters will appreciate a wide field of view because it's easier to track game.
- An exit pupil of at least 2 mm for day use, 5 mm or more for low light. The exit pupil gives you a rough guide to how bright your images will be in low light; the larger the number, the more light will come through to your eyes at dawn or dusk, at night, or in shadow. You can calculate the exit pupil of your binoculars by dividing the objective lens size in mm by the magnification size. For example, if you're using 8x42 binoculars, that gives you an exit pupil of 42mm / 8 = 5.25mm, which is good for use in low-light conditions.
- Fully multi-coated lenses. Coated lenses improve the brightness, contrast and color accuracy of the images you see through your binoculars by reducing the amount of light that's reflected away from them. Fully multi-coated lenses are even better; this means that all light-receiving surfaces are coated, both inside and outside the binoculars.
- A tripod socket. Although this isn't an absolute must, birders, astronomers and hunters will find it handy, especially if you're using large binoculars or a high magnification that lends itself to shaky images.
- Adjustable eye relief. If you wear eyeglasses, this feature is a must; look for an eye relief of at least 11 mm. (Eye relief is how far your eyes can be from the eyepieces before you start to lose field of view.) Some eyeglass wearers appreciate eye relief of 15 mm or more. Adjustable eyepieces are best because you can push them in to make room for your glasses, or pull them out to give you a comfortable view without your glasses.
- Fog-proof features. If you're spending more than $200 on binoculars, look for models that are fully waterproof and nitrogen- or argon-purged. These features keep moisture from getting into your binoculars and fogging up the lenses.
- Quality prisms. Roof prisms are generally preferred because they allow for smaller and more compact binoculars; however, for truly top-notch performance they must have a dielectric coating. Some people look down on binoculars with porro prisms because they make the binoculars larger and heavier, but they're also inexpensive and, as long as the prisms are high-quality, don't have to be coated to function well.
- Rubberized armor coating. A tough, rubberized armor coating protects the sensitive optics inside your binoculars from shocks and bad weather. This also makes it easier for you to hold on to the binoculars, and generally makes them feel better in your hand.
Know before you go
What will you use your binoculars for? This is what really determines which sort of binoculars you should buy. If you're using binoculars for stargazing, you'll want a high magnification with even larger objective lenses, and a tripod mount to keep the whole thing steady. Birders and hunters, on the other hand, typically appreciate 8x magnification and objective lenses in the neighborhood of 42 mm; this is the best balance between magnification, carrying ease and field of view.
How often will you use them? If you're truly dedicated to a lifestyle of birding, it might make sense to drop $2,000 on a truly expensive high-end set of binoculars. However, our Best Reviewed birding binoculars get you very close to the same image quality for around $600, and less frequent (or less obsessed) users can find very good binoculars for less than $300.
How to take care of your binoculars
Regardless of whether you paid $100 or $2,000 for them, your binoculars are an investment that should last. Never touch the lenses with your fingers or clean them with paper products like napkins, towels or newspaper; all of these things will scratch and eventually destroy the lens coatings that make your binoculars work so well. Never use commercial glass cleaners either; they contain ingredients that will damage the lens coatings.
Instead, go to an optics or camera store and purchase a spray-on lens cleaner, a lens tissue or microfiber lens cloth, and compressed air, all of which should be labeled as safe for use on camera lenses. Use the compressed air to gently puff loose dust off the binocular lenses, spray on the lens cleaner, wipe the lens, and then dry it with another piece of the lens wipe or cloth. Keeping your binocular lenses or eyepieces covered with the included caps will reduce the frequency of these cleanings and help preserve your investment for the long term.