Everything you Need to Know About Binocular OpticsAugust 17, 2018
If you’re looking to purchase binoculars, it’s important to first understand binocular specs, such as magnification, objective lens diameter and exit pupil. This will help you find a pair that works best for your own needs and type of activities.
Binocular size is defined by the objective lens size. Full-size binoculars (common specs: 8 x 42, 10 x 50) capture more light, and perform better in low-light environments. They’re best used for wildlife viewing, bird watching, and for use on boats, but they are too big and heavy for other activities. Mid-size ones (common specs: 7 x 35, 10 x 32) balance moderate size and above average light capturing, making these binocular optics perfect for wildlife and sports use. They’re still too heavy for taking on a hike or backpacking. Compact binoculars (common specs: 8 x 25, 10 x 25) are the best for outdoor activities. They are lightweight, small, and can be easily taken backpacking.
Binocular Magnification Power
There are two numbers that can be found on all binoculars. These numbers show magnification power and lens diameter. For example, 7 x 35 binoculars have a magnification power of 7, which means an object will appear 7 times closer than when seen with the naked eye. With magnification powers greater than 10, steady viewing becomes more difficult, as the binoculars are very sensitive to the natural shaking movements of the hands.
Binocular Objective Lens Diameter
This number refers to the diameter of the objective lenses. The objective lenses are those farther from the eyes and closer to the object being watched. For example, the same 7 x 35 binoculars mentioned above have objective lenses measuring 35mm. This diameter determines how much light the binoculars can gather, the larger the diameter, the more light the objective lenses will capture. And more light means a brighter view.
Binocular Exit Pupil
The exit pupil is a number that indicates how bright an object will look when watched in low light environments. The size of the exit pupil is calculated by dividing the diameter of the objective lenses by the magnification number. A larger number means a brighter image.
Binocular Eye Relief
The eye relief is the distance between each eyepiece and its corresponding eye while the entire field of view is visible. This spec is important for people who wear glasses, as a longer eye relief allows the users to hold the binoculars away from their face.
Binoculars optics are necessary if you’re planning to go wildlife watching. Make sure you know the right size you need, as the bigger ones are not portable. You can buy binoculars optics online or find them in physical stores.