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Understanding Magnification and Objective Lens



Understanding the Magnification and Objective Lens of my Binocular and Spotting Scope


Binocular size is defined by its magnification and objective, but if you are new to the hobby, what do these mean when observing. Below we have how to identify these two and how it a

affects your viewing.

Magnification Magnification is the degree to which the object being viewed is enlarged, and is designated on binoculars as the number preceding the "x." For example, when using an 8x42 binocular, 8x represents the binocular's magnification. An 8x magnifies an image to eight times the size it would be when viewed by the normal, unaided human eye. Similarly, a 15x70 binocular magnifies an image 15 times, and so on. The level of magnification also affects the brightness of an image: the lower the magnification, the brighter the image. In general, increasing magnification will reduce both fields of view and eye relief. Magnification is marked on many pairs of binoculars. Magnification Comparisons:

Objective Lens The objective lenses of binoculars are the front lenses. The diameter of one of these lenses, given in millimeters, will be the second number describing a particular binocular. Hence, a 7x42 binocular has an objective lens of 42mm. The diameter of the lens determines the light gathering ability of the instrument, with the greater light gathering ability of a larger lens translating into greater detail and image clarity. This is especially useful in low light conditions and at night. Doubling the size of the objective lenses quadruples the light gathering ability of the binocular. For instance, a 7x50 binocular has almost twice the light gathering ability of a 7x35 binocular and four times the light gathering ability of a 7x25 binocular. This might lead you to assume that bigger is better when it comes to the diameter size of the objective lenses. In reality, the size of the lens must be considered along with the exit pupil and intended usage to determine the best binocular for your personal use.

(Not a European Robin)

Variety of Uses Based on the magnification and objective lens of your binocular, below are some suggestions on what you can use your binocular for. Magnification LevelObjective Diameter25mm - 30mm32mm - 35mm40mm - 42mm50mm - 56mm60mm70mm80mm100mm6x - 7xHiking, Camping, Sporting Events, ConcertsBirding, Travel, Sporting Events, Concerts, General PurposeSporting Events, Astronomy8x - 9xHiking, Camping, Sporting Events, ConcertsBirding, Travel, Sporting Events, Concerts, General PurposeBirding, Travel, General PurposeBirding, AstronomyAstronomy, Seawatch10x - 12xHiking, Camping, Sporting Events, ConcertsBirding, Travel, Sporting Events, ConcertsBirding, Travel, HuntingBirding, Astronomy, Hunting, Law EnforcementAstronomy, SeawatchAstronomy, Seawatch, Law Enforcement15x - 16xTravel, Sporting Events, ConcertsAstronomy, Hunting, Law EnforcementAstronomy, Seawatch, Law Enforcement20x - 25xAstronomy, Seawatch, Law EnforcementAstronomy, Seawatch, Law EnforcementAstronomy, Seawatch, Law Enforcement

For information on Field of View, click here.

(C) Celestron

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