Select the right pair of binoculars for your planned activity.
The first number in the description refers to how many times the binoculars will magnify an object. Keep in mind, the higher the magnification, the less field of view you have with your binoculars. Higher magnification makes it more difficult to pick up moving objects, such as birds.
The second number indicates the diameter of the objective lens. A larger objective lens means more light will be let in the field of view. However, a larger lens diameter does mean a heavier pair of binoculars.
Binoculars come in a variety of brightness levels. The size of the exit pupil determines the binoculars’ brightness level. Divide the lens diameter by the magnification power to determine the size of the exit pupil. A 3-mm to 5-mm exit pupil is generally adequate for normal viewing. A 7-mm is best for low-light use.
Select binoculars that are waterproof so there is no need to worry about an unexpected rain shower or spray of water.
Choose binoculars with eye relief of at least 10 mm. Eyeglass wearers, consider high-eyepoint binoculars with eye relief of 15mm or longer.