When buying binoculars, consider the magnification, size of the lens, weight, overall size and angle of view. The choice of binoculars is dependent on the budget, the primary use of the binoculars, who will be using the binoculars and special requirements like poor vision.
Magnification refers to how much larger the binoculars make a subject appear. Consider the size of the objective lens at the front end of the binoculars. A large lens allows more light to pass through it, producing a clearer and brighter image, especially in low light.
The terms “angle of view” and “field of view” describes the width of the area seen through the binoculars when expressed in degrees. A wide field of view makes trailing moving objects easier. Large, higher powered binoculars give a smaller field of view than lower powered binoculars.
Anti-glare coatings allow light to go through the lenses without glare. Binoculars with multiple coatings on all the lenses give clear and bright images; these coatings are found on many of the more expensive binoculars.
The weight of binoculars correlates to the quality of the lens and in return the quality of the image. If the diameter of the objective lens is substantially reduced to bring down the size and weight of the binocular, the quality if the image produced is also reduced.