by 
The Curious Bag
-
Numbers on binoculars represent magnification, aperture, and viewing angle. An understanding of these numbers provides the key to getting the binoculars you need for wildlife, sports or astronomy viewing.
Magnification
The first number, followed by an "X," is the magnification. The binoculars show an item that many times larger.
Aperture
The number after the "X" is the aperture. It is a measurement, in millimeters, for the diameter of the front lens of the binoculars. A larger aperture allows more light to enter the binoculars, and a wider viewing angle.
Viewing Angle
The viewing angle expresses how many feet across you will see at 1,000 yards. If the binoculars say 240 feet, the binoculars will show that wide of an area at 1,000 yards. The Monk Optics website reports that the field of view can be measured in degrees as well.
Degrees
The degrees represent how much of a circle, at 1,000 yards, appears through the binoculars.
Light
The more light entering the binoculars, the brighter the image, says HawkeOptics.com. A smaller aperture has a bright image in daylight, but provides a dark image in the early morning, late evening or at night, when you need a wider aperture for comfortable viewing.
Source:
Resource:
Binoculars 101
RELATED QUESTIONS
Copyright 2023, Wired Ivy, LLC