What do the Numbers on a Scope Mean? – All You Need to Know

What do the numbers on scopes mean?

Knowing what these numbers mean is critical to shooting right at the target. 

So in this guide, we will talk about each and everything you need to know about the numbers on a scope (and not just the two main ones). 

Let’s get started. 

What do the numbers mean?

What do the Numbers on a Scope Mean?


Magnification power is denoted by the first number on the scope. The size of the objective lens is denoted by the second number on the scope.

Note: If you want to gain a complete guide about scopes click HERE.

Rifle Scope Magnification Explained

Magnification is a physical property of a lens. Lens thickness, curvature, and diameter affect how much light passes through the lens. Coatings also affect the amount of light passing through the lens.

Lenses inside a scope perform 3 primary functions:

  1. A magnifier lens captures light reflected from an object and bends the light to form a magnified image of that object.
  2. Some scopes use more than one lens to magnify the target
  3. Others use an erector assembly to flip the image upside down.

A telescope is an optical instrument used to view distant objects or events by focusing light onto a photographic plate or other sensors. Telescopes come in many sizes, ranging from pocket models to large observatories.

The Magnification Equation Determines the Size and Distance of the Magnified Image.

Magnification is used to make objects appear bigger or smaller. When magnifying something, it makes it seem farther away. For example, when looking at a person through a telescope, it looks like they’re standing far away because they’re magnified.

A magnifying glass doubles the magnification by increasing the focal length of the lens by 2x. Doubling the magnification from 3x to 6x causes the target to appear twice as close and four times as large.

Note: If you want to gain information about How to Sight in a Leupold Muzzleloader Scope Click HERE.

Physical Limitations of Magnifying Lenses

Magnification comes with trade-offs. Distortion is often present when magnifying an image. This may be due to the fact that light rays must pass through more glass or plastic than air. In addition, there are many optical limitations and different types of distortion that are associated with magnification.

Chromatic Aberration

Chromatic aberration is caused by different wavelengths of light interacting with a glass surface differently. When viewing images through a microscope, chromatic aberration appears as a purple fringe around objects.

Field Curvature

In low magnifications, targets and reticles appear blurred because of field curvature. Field curvature occurs when the lens bends light rays as they pass through the lens. This causes objects farther away from the camera to be out-of-focus.

Note: If you want to know Who Makes Leatherwood Scopes? Click HERE.

Spherical Aberration

As the magnification increases, spherical aberration may occur. Spherical aberration occurs because light bends more at the edges of the lens than at the center. When this happens, the light coming from the edges of the lenses meets at a different focal point than the central part of the lens. This causes the image to be blurred at the edge.

Field of View

The field of view decreases as magnification increases.


A magnifying glass is made up of many thin lenses. When you use a magnifying glass, you’re using a lot of lenses. This means that when you use a magnifying lens, you’ll get a dim image because there are a lot of lenses involved.

Note: If you want to know How to Sight in a Nikon Buckmaster Scope Click HERE.

Making a Choice – Rifle Scope Magnification vs Distance

Magnification is the amount of power used to make an image larger or smaller. Higher magnification means a bigger image. Too much magnification causes problems, including weight, complexity, and distortions. Most people use magnifications of 3-6x when shooting.

High magnification is needed for long-range hunting. Low magnification is needed for close-up hunting.

This scope is great for hunting. You can see your target easily because it has a fully multi-coated lens. It also has quick view technology.

Exo barrier protects your eyes from dirt and dust. It also keeps out water and oil. It’s waterproof. It’s made by Bushnell.


When choosing a scope for your gun, consider that as magnification goes up, brightness decreases. A bigger lens costs more money but also weighs more. Higher magnification doesn’t always mean better quality. Lower magnification provides more light.

Scope Magnification Explained

Scope magnification is measured by how much an object appears larger when viewed through a particular type of optical device. For example, if you were looking through a telescope, the image of the moon would appear about 1/4th as large as it does to your unaided eyes. However, if you were using a microscope, the image of the same moon would be magnified to over 100x.

Scopes from every country or region use the same approach to magnify things. This means that if you have a scope that uses a different approach than the one above, your output won’t be correct.

Scope Types

Riflescopes are used to help shooters aim at targets. There are two types of rifle scopes: fixed power scopes and adjustable powered scopes.

Fixed Powered Scopes

A fixed power scope is a type of scope that has a fixed magnification setting. These scopes were very popular in the 1960s and 1970s because they were inexpensive and easy to use. Fixed power scopes tend to be fairly simple to operate as they usually don’t have an adjustable lens. Most fixed power scopes also have a fixed parallax.

A simple scope offers no adjustments. Fixed-power scopes feature a magnification range from as low as 2x all the way up through a fixed 20x power (or higher). Most popular fixed-power scopes include the 4x, 6X, and 8x models (and higher).

Fixed power scopes were once popular but now adjustable ones are more common.

Variable Power Scopes

Variable power scopes feature a very low range of magnifications, while modern ones feature a range of magnifications that average eight magnifications but can go as high as twenty-five magnifications.

Variable powered scopes have almost become the industry standard as there aren’t many fixed powered scopes left. Most people use variable-powered scopes because they offer a wide magnification range.

The other numbers…

There are a few other numbers that you’ll see listed in the scope specification that we should also cover as well.

Eye Relief inches or mm – range

Eye relief tells you how close or far away your eye has to be from the eyepiece of the scope in order to see the full field of vision. Lower power scopes usually have a larger eye relief than high power scopes.

Typical eye relief for rifles and high-powered weapons is 3 inches (7.62cm). You should never aim more than 4 inches (10cm) away from the target.

A spotting scope lists the distance between the objective lens and the eyepiece as eye relief. Eyeglass wearers should be aware of how far their eyewear pushes their eyes out of focus. Spotting scopes usually offer a range of eye reliefs, and the most common ones are 8-12mm.

Exit Pupil mm

The exit pupil should be as big as possible without wasting any light. In daylight, the human iris is about 3mm wide. In low light, it’s 4mm wide. And in near darkness, it’s 6mm wide.

Tube Diameter mm

A rifle scope has a larger tube than a crossbow scope. This means that the riflescope can be adjusted higher up from the barrel than a crossbow scope can.

Length inches or mm

This is the longest length of scope from tip to tip

Weight kg or oz

A scope adds weight to a rifle. You should weigh the scope before buying it.

Size of the Objective Lens

Larger lenses have a bigger diameter and allow more light to enter the scope. This makes them easier to focus. Low light conditions make it harder to see what you’re aiming at.

Riflescopes are generally smaller than binoculars. Binoculars are designed to be used for long distances, while rifle scopes are designed to be used at close ranges. Lenses are made larger when using riflescopes instead of binoculars.

Spotting scopes do not require large objective lenses because you’re usually looking at a single target. Binoculars need more light to see a larger area. A spotting scope allows you to see a bigger area while hunting.

This article contains information about how to find the best 1-6x scopes.


A minute of angle is used to determine how much your bullet deviated over a given distance. Your rifle is at a 1-minute angle if your bullets hit within an inch circle.

At a distance of 200 yards, your rifle is still at 1 minute of angle even though your bullets hit within a two-inch circle. Shooting a ten-inch group at a range of 500 yards can be said to be 2 minutes of angle.


Bullets travel in arcs when they’re fired from a gun. A bullet travels in a straight line if it’s fired from a close range.

A .22 caliber rifle bullet travels about 2,200 feet per second. At 100 yards, this means the bullet travels about 0.2 miles per hour. This is very slow compared to other calibers such as .308 or 7mm Remington Magnum.

What Determines the Scope’s Magnification?

Scope features are important because they affect how well a scope works. There are many different types of scopes, but these numbers are what make them work.

Objective lenses are used to magnify objects. In this case, the objective lens pulls an image into the scope. The objective lens adjusts the light and zooms it through the back where the user looks through it.

Magnification number 2 is thicker and thinner lenses offer varying magnification numbers. Thin lenses don’t zoom as far and last as long. Anti-glare or anti-fog coating helps reduce glare and fogging. Longer riflescopes have more room to zoom farther than shorter ones.

Adjusting the magnification of your rifle scope is easy. Most riflescopes have a ring that lets you turn the scope up or down. This ring is usually located near the top of the scope. Twist this ring clockwise to increase the magnification, counter-clockwise to decrease the magnification.

The focuser is used to help zoom in or out on an image. You can use this tool to adjust the clarity of your photo.

Scopes are more complicated on the inside but less complicated on the outside. Manufacturers spend lots of time and money to make scopes perform well. To increase magnification, they only need to bend the lenses and lengthen the scope. To increase its size, they only need to widen each part.

Diameter Numbers Are Often Based on Personal Preference

A scope’s diameter should be chosen based on the distance you intend to shoot. For example, if you plan to hunt deer out to 300 yards, then a 10-power scope is appropriate. If you plan to hunt deer up to 1,000 yards away, then a 20-power scope is more suitable. Practice shooting at a range before using your new scope in the field.

Magnification is how much an image appears larger or smaller when viewed by the human eye. The diameter is the size of the lens in millimeters. A 50mm lens is half as wide as a 100mm lens.

Diameter Numbers Are Static

A scope’s diameter number should never be changed because it’s set by default. You shouldn’t choose a smaller diameter than what your eyes need. Your eyes may get tired if you use a larger diameter.

Choose the Proper Field of View for Your Scope

Don’t settle for a limited-diameter scope in favor of good magnifying power. You might strain your eyes and deal with headaches, as mentioned earlier. Look down several scoped before making a decision, particularly if you’ve never owned a scope before.

Consider Exit Pupil Dimensions

Exit pupil size should be a minimum of two millimeters to six millimeters. Aiming Expert shows that if the exit pupil is smaller than this range, the scope may appear distorted or blurry.

Should I Buy a Binocular Spotting Scope or Telescope?

Binoculars are great for beginners because they are easy to carry around and use. Spotting scopes are ideal for hunters who need to get closer to the game. Target shooting requires a higher level of accuracy than most people are used to. A spotting scope allows you to see what you’re aiming at.

Telescopes are used for astronomy. Spotting scopes are used for observing subjects on land or at seas. Spotting scopes would be useful if you want to view boats in the bay, ship on the horizon, scenery up to 30 km away, or simply observe subjects at a very long distance.

What is the Ideal Lens Size?

Spotting scopes with larger lenses are better because they gather more light. Smaller lenses are cheaper but produce less bright images. Bigger lenses are more expensive but weigh less.

A spotting scope should be chosen based on your needs. If you’re going to use it for a long time, go for an 80mm model. If you want to carry it around a lot, get a 50mm model. You can also use a 50mm model if you don’t want to carry any extra weight.


Remember to consider weight when buying a scope. We hope that you have a better understanding of what the numbers mean on a scope.

Although we have mentioned everything you need to know in this guide, if you feel there is any further information you need to know, please feel free to reach out to us.

If you want to know more information about scopes click HERE.

Happy shooting!


  • John Moses

    John is the Editor in Chief here at The Outdoor Stores. His area of expertise ensures that there is no one better to suggest which rifles are most suitable for your hunting experience. He is also available for you to contact him personally to discuss the types of animals you want to hunt and the terrain you will be hunting on. Feel free to read his posts for expert opinion on Rifles, Scopes, Rangefinders, Bonoculars and Monoculars.

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