What makes a binocular appear brighter?

Brightness in your binoculars can be affected by several things. Contrary to what many binocular users believe, big objective lenses are not the only factor to consider. The quality of glass used in binocular prism and lens construction along with the quality of the lens coatings on the binocular contribute more to brightness than do big objectives.
     Lens coatings are thin layers of chemicals applied to the glass surfaces of the binoculars. These coatings improve light transmission through the binocular. Coating quality is affected by the number of coatings and whether all binocular lenses, inside and out, are coated with several layers of coatings.
     Ideally, you should purchase binoculars that are fully multi-coated, which means both sides of every binocular lens are coated with at least several layers of the anti-reflective chemical. High quality lens coatings will appear as fairly light, subtle shades of blue, green or violet.
     A word of caution, beware of a binocular using heavily colored lenses. These lenses will only cut down on light transmission through the binocular.

Note: If all other things are equal in two binoculars, a binocular with a larger objective lens will yield a brighter image, but at the cost of greater size and weight. Higher quality binoculars with a smaller lens may very well be brighter than less expensive binoculars with larger objective lenses.

List of common binocular questions.




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