How to Evaluate Glass Quality of a Scope?

The glass or lens is one of the essential parts of a rifle scope.

Regardless of how high-tech your scope is, you won’t get much use out of it if the glass quality is lacking.

So, this begs the question, how to evaluate glass quality of a scope?

In this article, we’ll outline some things you should be on the lookout for regarding your scope.

We’ll identify some potential signs that will tell you if your glass quality is degrading or not.

Do Scopes Degrade with Time?

quality degrades with time

Regardless of how high quality your glass scope is for your rifle, heavy use and time will inevitably cause it to break down.

This degradation can manifest in several ways and can be an incredible deterrent to your gun’s performance.

Lower quality scopes will have scratch marks on their glass, making it more challenging to focus on targets.

Another common issue with scopes that have marks on them is that the lines can get eroded or faded with harsh weather conditions.

Since these lines are important in determining distances accurately, having the lines faded can mess up your aiming.

Some lines are etched into the glass, and although they have better resistance, they too can degrade with harsh weather conditions or if the lens is damaged.

Dust and dirt getting into the rims of your lens can also lead to a decline in performance. This will affect the clarity of your scope and make it harder to focus over long distances.

It will also affect the brightness of your glass, preventing most of the light from entering. As a result, you will be unable to aim in lower light conditions.

How to Evaluate Glass Quality of a Scope?

rifle scope quality

To understand how good your rifle scope lens is, you will have to rely on a trial and error method. You will need to try out your scope in various conditions and keenly lookout for clues.

There are primarily three bases on which a rifle scope’s glass is evaluated.

These are:

#1. Optical Clarity

optical clarity is important

One of the most important things about your rifle scope is how clear it allows you to see over a particular distance. Many modern rifles have a wide power or magnification range, enabling you to zoom over large distances.

However, the ability to magnify your image will not help you much if your glass doesn’t have good optical clarity. As a result, everything will look blurred and distorted and make it harder to aim.

Some low-quality glasses might have the line-markings merge when you’re zooming in. If you notice this when using your scope, it is a bad sign and shows poor craftsmanship.

The best way to test the optical clarity of your lens is to simply put the scope on your rifle and go through the various magnification settings.

Pay close and proper attention at the end of the power range (highest magnification settings). If you see the clarity decrease at settings like x15 power, your glass is average or mid-range glass quality.

A sign of high-quality glass is if there is no distortion or blurriness at the highest magnification settings.

So, be sure to examine the view at x18 to x20 thoroughly.

#2. Brightness

check brightness

An important task that rifle scope lens do is that they allow light to enter. High-quality glass has a more powerful light-gathering capability, enabling it to work in much darker or low-light areas.

Entry-level or budget glasses tend to not work as effectively in low-light environments, resulting in a much darker view when using the lens.

If you want to evaluate your rifle scope lens, you will need to try it out in various brightness settings.

In conjunction with the light-gathering capabilities of your glass, you should also test the clarity by changing magnification. These two are the most important ways to evaluate your glass quality.

With time, the light-capturing ability of your lens can deteriorate, so pictures appear dimmer.

Unfortunately, this will also affect your ability to hunt or aim during the night or in darker areas.

#3. Color

color quality

Although not as important as clarity or brightness, color is still an alternative way to evaluate glass quality.

The low-quality glass will often alter the color of what you’re viewing through your lenses. These slight alterations in hues can prove disorientating.

Make sure to check whether the returned colors are the same as your glass in different brightness settings or not. This can be an early sign of a poorly constructed rifle glass.

Order of Evaluation

We have listed three primary characteristics you should evaluate your scope glass with. Out of these three, the main deciding factors are clarity and brightness.

When taking it out, you can perform a color test to see if the returned colors are the same or not. Once the color test is done, you can move on to testing the magnification and brightness.


Knowing how to evaluate glass quality of a scope is a valuable lesson for every rifle user.

Remember that you need to be thorough and patient with your evaluation, especially when examining optical clarity and the light capturing ability.

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