Spotting Scopes 101: Magnification and Objective Lenses – What do the numbers mean?

spotting scope

Do the numbers in spotting scopes hunt and scare you? It may look like doing math all over again but trust me, it’s easier than you think! The numbers talk about the magnification power of the spotting scopes and the size of the objective lens. Let’s take this slowly, shall we?

There are always two parts in the set of numbers: magnification number and objective lens size. I’ll start with the magnification number. This tells you how close you can view the image through your spotting scope. To understand this better, let’s take this set as an example:


The first part, 3-9x, means you can view the object three times to nine times closer through the scope. That means every time you see two numbers separated by a dash, they indicate the range of the magnification. The higher the second number, the higher the range and the greater the magnification.

Now, what about the 40? It may or may not come with a “mm”, but this refers to the diameter of your objective lens. Simply put, it’s the size. If you don’t know what the objective lens is, it’s the one closer to your object.

Spotting scopes magnify better compared to binoculars and that’s why they’re used for hunting, birdwatching, and wildlife viewing. With a spotting scope, you don’t have to get physically closer to your target just to get a better view. You can easily adjust the variable zoom eyepiece and it can reach its highest magnification capability easily.

The objective lens of the spotting scope also affects the quality of the image. A bigger objective lens will give a better image than a smaller one especially when you need to use the highest magnification of the scope. However, it’s important to value the quality of the image over the size of the objective lens.

If you want to upgrade your spotting scope, you can do so by purchasing HD glass, APO glass, Fluorite glass, or ED glass for your objective lens. They can give a sharper image, especially at higher magnifications. The upgrade might cost a lot, but it’ll be worth it. However, if you have an unlimited budget, don’t think twice—get yourself a spotting scope with a large objective lens that performs great even at higher magnifications.