What Do the Numbers on Binoculars Mean? – Everything You Need to Know with Professional Advice

What do the numbers mean on a binocular?

It is a question most of us ask.

Let’s find out!

What do the Numbers Mean?

Objective Lens Size Aperture

Binoculars have an objective lens size of 50mm. They are wider than normal binoculars.

Moreover, binoculars with larger lenses gather more light than those with smaller lenses. A 10×50 binocular gathers more light than a 10×25 binocular. Thus, the 10×50 binocular is better for seeing stars in the night sky.

Note: If you want to know information about What Kinds of Binoculars Are Good for Bird Watching click HERE.

Understanding Angle of View

The angle of view refers to the angle of your view of the horizon. The field of view is the width of the scene that you see through the binoculars or telescope. You can calculate the field of view by multiplying the focal length (the distance between the lens and the object being viewed) by the magnification factor. For example, if you were using a 10x50mm scope, then the field of view would be 50 times 10, or 500 mm.

A good angle of view is usually between 6 and 10 degrees. Anything above this range is considered a great angle of view. Binoculars with a very high angle of view can be used for long-distance viewing.

A 10×50 binocular has an actual angle of view of 72 degrees.

Note: If you want to know How to Focus Binoculars click HERE.

Understanding Field of View

Field of View (FoV) isn’t expressed in degrees, but instead in either: feet per 1000 yards or meters per 1000 meters. A higher number simply means you’d have a wider horizontal view. You should typically consider an FoV of around 300-375 feet as adequate.

However, remember that the higher your magnification level, the narrower your field of view will become because the object is brought closer.

A 378-foot field of view means that if you’re standing at the back of a room, you’ll be able to see everything in the room.

Eye Relief Number

Binoculars usually come with different numbers indicating the distance between the eyepiece and the user’s eyes. This information is useful when wearing glasses.

Exit Pupil Number

Binoculars are used by people who want to see things far away. A pair of binoculars allows the user to focus on an object up to 100 yards away.

Binoculars with a smaller exit pupil (3.1mm) are better than those with a larger exit pupil (5mm). Bigger is better.

Note: If you want to know more information about Binoculars click HERE.

Close Focus

Binoculars have a close focus of 13 ft. You can see objects as close as 13ft away.

A Quick Checklist

Binoculars are used to see things up close. A higher objective lens diameter means a larger field of view. Magnification means a smaller field of vision.

“Look for an eye relief of less than 15mm if you’re wearing glasses. An exit pupil of less than 4mm is recommended. Pay attention to a short close-focus if you want to magnify very close objects. “

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what do the numbers on binoculars mean

What Do the Numbers on Binoculars Mean?


Binoculars are used to watch birds or animals. A large aperture allows more light into the lens, making it easier to see objects in dim conditions.

However, a smaller aperture makes the image appear sharper.

Moreover, magnification is the number of times the object appears larger than life-size. Thus, higher magnification means less room for error.

If you want more information about Binoculars click HERE.

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