What To Look For
Look for binoculars with large front lenses, or apertures. Every binocular has two numbers on it, such as 7x35. The second refers to the aperture, or the diameter of the front lens. Large apertures let in lots of light, which is necessary for night activities such as star-gazing, according to Sky and Telescope.
Keep in mind that large front lenses increase the weight of the binoculars. If you plan to carry them for long distances---such as on hikes---look for mid-size binoculars with apertures between 30 mm and 39 mm, as REI recommends. Otherwise, choose binoculars with apertures of 40 mm to 50 mm for optimal night vision.
Common Pitfalls
Don't forget to consider the exit pupil. This is the opening that allows light to pass through the binoculars to your eyes. It should match the natural dilation of your pupils, which changes as you age. People younger than 30 tend to have pupils that dilate about 7 mm, while the pupils of people over 40 usually dilate 5 mm, according to Sky and Telescope. Look for the same size exit pupil. To find the exit pupil, divide the aperture number by the first number. For instance, 7x35 binoculars have exit pupils of 5 mm.
Where To Buy
Chain stores such as Best Buy and REI sell binoculars, though selection varies from one store to the next. Nikon, Olympus and Canon also sell binoculars and are known to provide quality products and service. For the widest selection and competitive prices, visit websites such as EagleOptics.com. Keep in mind that ordering online means forfeiting the right to test your binoculars and get a feel for their weight before buying, though you can get around this with websites that have 30-day return policies.
Cost
Mid-size binoculars, which REI recommends for both day and night use, typically cost $100 to $300. Budget-conscious shoppers might find bargains under $100, though William J. Cook, optical expert for the U.S. Navy, warns that prices tend to match quality. If you plan to use your binoculars outdoors and want a waterproof design, prepare to pay slightly more.
Comparison Shopping
The two main types of binoculars are Porro prisms and roof prisms. Porro prisms are bulkier, but Cook states that they offer the best depth perception. Meanwhile, roof prisms, which have eyeholes in direct alignment behind the front lenses, are lightweight. This makes them slightly more comfortable for carrying, but they are pricier due to their complicated design.
Insider Tips
If you wear glasses, consider the eye relief before purchasing. A greater amount of eye relief allows you to hold binoculars slightly away from your face and still see the full image through them---a particular concern to people whose glasses get in the way of them pressing their faces against the binoculars. Cook recommends eye relief of at least 15 mm to accommodate for glasses.
Member Comments