Spotting Scope Numbers: What do they mean?

Let’s talk about spotting scope numbers. Ever wondered what they mean? I did too, when I was a beginner.

Take a spotting scope with 20-60×80 written on it. 

spotting scope numbers

Example: 20-60×80

20-60 is the Magnification range

The first set of numbers (20-60) represents the magnification range. This means you can adjust the zoom from 20 to 60 times closer than your naked eye. It’s like having superhuman vision!

  • Everything seen through the spotting scope will appear 20-60 times larger than with the naked eye.

When it comes to magnification, there isn’t a one-size-fits-all answer. What’s considered “good” really depends on what you’re using the scope for. 

  • Birdwatchers might prefer a lower magnification for a wider field of view.
  • Hunters might want a higher magnification to spot animals from a distance.

80 is the Objective Lens Size

The number after the ‘x,’ in this case, 80, represents the diameter of the objective lens in millimeters. 

A larger objective lens lets in more light, giving you clearer and brighter images, especially in low-light conditions. 

Example: 4×32

4 is the Magnification

Just like above, the number before the X is the magnification range. 

  • In this case, there is no range. The magnification is a fixed 4 times zoom. 
  • The magnification is not adjustable; everything viewed through the scope will be 4 times closer than with the naked eye.

32 is the Objective Lens Size

The number after the X is always the objective lens diameter in millimeters. In this case, 32mm. 


What range to get?

  • Bird watching: A spotting scope with a magnification range of 20-60X is perfect. This range offers enough detail for most birding situations.
  • Hunter/Shooter: Depends on the distance of the target. For targets at 100 yards, a magnification of 20-40X is sufficient. But if you’re spotting targets/animals at greater distances, you’ll want a scope that can go up to 60X.
  • General use: 15-60X is a good range. This gives you the flexibility to spot details at various distances.

Higher magnification isn’t always better. As the magnification increases, the image quality can degrade, especially if the scope isn’t expensive like a Swarovski.

Objective Lens Diameter

The objective lens diameter is the size of the front lens on a spotting scope. This lens captures light, and a larger lens can capture more light. 

Most spotting scopes have an objective lens ranging from 50mm to 80mm. 

The size you choose depends on what you’re using the scope for and the conditions in which you’ll be using it.

  • Bird Watcher: A spotting scope with an objective lens size of 60-70mm is optimal for bird watchers. It provides a good balance between brightness, clarity, and portability.
  • Hunter/Shooter: If you’re a hunter or shooter who needs a clear view in varying light conditions, a larger objective lens (65-85mm) is a better choice. Remember, though, these scopes can be heavier, so if weight is a concern, you may want to stick to a 60-65mm lens.
  • Other Uses: A smaller objective lens (50-60mm) will work for casual nature observation or if portability is a primary concern. They’re lighter and easier to carry but might not perform as well in low-light conditions.

Wrapping it Up

So, understanding spotting scope numbers will help you choose the right scope for your needs. 

Whether you’re birdwatching, hunting, or just exploring, knowing how to read these numbers will make everything much easier.

There are a few more key terms you need to know: field of view, eye relief, and exit pupil. I’ve kept this article focused on the main spotting scope numbers – magnification and objective lens diameter. If you’re unfamiliar with the other terms, check out my beginner’s guide. There, you’ll find all the essential information to get you started.

About the Author

Logan Scott

I love the outdoors, hunting and spending my time exploring the pacific north west.

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