What Do Spotting Scope Numbers Mean?

Today I will talk about the best and powerful optic tool to enjoy sight or land view and bird watching. To get the best spotting scope, you have to know a lot about the scope.

Even if you know what you are taking, the numbers of the scope will confuse you a lot. What do these spotting scope numbers mean?

Don’t get frustrated with the numbers as they are easy to understand. How? Let me explain.

What do the numbers mean?

I will try to explain the numbers in a simple way. Do stick with me:

Spotting scope numbers:

In a spotting scope, you will find two sets of numbers like 20- 60 x 80mm. Let me explain this number:

  • Here the number 20 is the least magnification power of the scope.
  • The second number 60 is the topmost power magnification level.
  • Between the two number, there is a hyphen that separated the numbers. The hyphen is known as zoom scope.
  • The x before the 80mm means the diameter of the objective lens in mm.

Note: remember if the x comes before the number then it means the diameter of the lens and if the x comes after the number than it stands for the power range.

You will find another type of number like 4×32.  This number represents:

  • The number before the x is 4 and it means the magnification power is 4x. the number after the x is 32 and it means the objective lens is 32 mm. though there is no mm, the standard size of the optical lens comes in mm. There is no option for zoom scope.

Some scope comes in these numbers like – 5x scope or 8x scope.  These numbers represent the number of magnification power. Like 5x means 5 times magnification power. Still confused? Well, the simple meaning is the picture will come in 5 times bigger when you see through the scope.

The objective lens size:

An objective lens is for letting in the light. The larger the lens is the much light will enter in the lens. The lens makes the image clear and bright even in low light.

From the binocular lenses, the spotting scope lenses come in a bigger size. Why? Because with the lenses you can enjoy the birds flying home in the dusk. As the dusk time, there is less light, you can have a bright picture in high magnification like 80 x or 60x.

The question is what is the ideal lens size? It is up to you, what you want? Better image quality or lighter and smaller spotting scope? At first, you have to know where you will use the scope. For a fixed location take an 80mm scope, to travel take a 50-60 mm scope.

Few other numbers:

There are more other numbers that you will find a spotting scope. Here is the explanation of the numbers:

Field of view:

The field of view gets narrower for magnifying power. In the scopes, there are different parameters that provide different magnification. You have to use the magnification power per your requirement.

The standard range of the field of view of a human is 210 degrees. You can adjust the range with a scope.

With a bigger field view, the picture or the object gets clear and easy to spot. You can also have a great view of a moving object.

For an example, spotting scope magnification for 1000 yards @ 100-142 ft means you can see the 100th field of view at 1000 yards without any scope or binoculars.

Eye relief:

There is a common question about what does eye relief on a scope mean? Well, the eye relief is the measurement of the closeness on the eyepiece of your eye.

This measurement depends on the magnification power. The low magnification power has a large distance eye relief and the higher one requires close distance.

There is a standard measurement of eye relief in most of the spotting scopes and that is 16.7-17 millimeters. In this range, your picture will be clear, but more than this range will not allow you to see a clear picture.

Eye relief is best for them who wears eyeglasses. A thick glass wearer can also have a clear view in 12-16 mm distance, thanks to the eye relief.

Exit pupil:

The exit pupil of a scope means the diameter of the light that enters the eye after leaving the scope. The diameter of this exit pupil comes in different mm like in the dark night it comes in 6mm, in low light it comes in 4-5 mm and in the day is 2-3 mm.

Tube diameter:

For a spotting scope, the tube diameter is for adjusting the scope. The tube has no function in optical quality. Many scopes have tubes that come in one inch in diameter. Some scopes have a thirty-millimeter tube.


The spotting scope comes in an ounce or kilogram when it comes to weight. The scope is heavy and hard to hold for a long time. you will need a tripod to have support while sight-seeing. make sure to know about the number before dealing with a tripod.


The length is the measurement of the scope from top to bottom. It comes in an inch.


The best spotting scope makes your adventure interesting and enjoyable.  But for the new users, the numbers make the little-complicated situation. But the truth is the numbers just talks about the magnification power and the objective lens size.

You may think to use a binocular, but the scope magnifies is much better and perfect for wildlife, birdwatching, and hunting view. Just put the scope in perfect position and enjoy the view in a safe distance without disturbing your target.

You can add an adjustable eyepiece and magnify power per your requirement. So, don’t get confused with the number, just go through this post. You will get help and enjoy your time with the scope.

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