What Is a Prism Scope: Prism Sight Optics Explained

Typically, choosing traditional rifle scopes means looking for something that offers long-distance accuracy and targeting. However, if you’re mostly shooting within the zero to 200-yard range, a prism scope may be a better option. 

Let’s break down why a prism scope might be ideal for your firearm. 

What Is a Prism Scope? The Basics

A prism scope is a telescopic sight that uses a prism to magnify the image coming in through the objective ocular lens. These sights work differently from most other scopes with a lens array, allowing for better magnification.

A prism scope also has an etched reticle rather than a projection. Because of this, you can use the sight without power, and it’s much easier to focus. Another advantage of this setup is that it’s easier to have an illuminated reticle without battery power. 

Pros and Cons of Prism Scopes

If you’re considering getting a prism sight for your rifle, it’s crucial to understand its benefits and disadvantages. Here’s a breakdown of both pros and cons of this type of scope: 

Pros

• No battery power needed
• Better magnification compared to red dot sights
• Comes with a diopter to help zero out the scope
• Helps shooters with astigmatism (using the diopter allows it to be adjusted to anyone’s eyesight)

Cons

• Short eye relief
• Heavier than red dot sights
• No variable zoom settings

What Are The Best Prism Scopes?

If you’re looking for specific recommendations, we have an entire article on the best prism scopes on the market today. We review the top models to bring you our list.

How Does a Prism Scope Work?

Prism sights generally work the same as binoculars to provide fixed magnification and clarity. First, light enters through the front of the scope, which has an ocular lens to capture and focus light as much as possible. 

The light hits two prisms – one roof prism and a mirror prism – and reflects off of them, magnifying the image in the process. Finally, the light exits through the eye relief so you can see the image clearly. (2)

Red Dots vs Prism Scopes

Prism and red dot sights are often compared because they’re used for similar tactical rifles. Compared to a traditional lens scope, both red dots and prisms have a shorter range and faster targeting. 

So, let’s break down how a prism scope differs from a red dot sight. 

Differences Between Prism Scope vs Red Dot

• Magnification Setting – A red dot sight doesn’t allow for magnification, so you can only see your target as it appears in front of you. 
• Eye Relief – Because red dots don’t magnify the image, you can see into the scope immediately. A prism scope has a shorter eye relief, so you need to be closer. 
• Power Source – Having an etched reticle means you don’t need a battery with a prism. However, a red dot sight needs a battery to work. 
• Diopter – With no magnification setting, there’s no reason to “zero out” a red dot sight or reflex sight. Prism models come with a diopter for more precise shooting. (1) 

Pros and Cons

Pros of Prism Scope vs Red Dot

• More accurate
• Easy to install
• No power required for prism scopes
• Has a diopter like a traditional rifle scope
• Can include magnification (red dot reflex sight has 1x aiming point)

Cons of Prism Scope vs Red Dot

• Not as light as a red dot
• Has shorter eye relief

Our Recommendation: Which is Better? 

Overall, if you’re looking for fast targeting, a red dot sight is better. However, a prism scope is much more reliable for precision and magnification.

If you’re looking for more related reading, check out: prism scope vs red dot sights.

Frequently Asked Questions

What is a prism scope good for?

A prism scope is often good for relatively short-range shooting thanks to its reduced magnification and lightweight design. Many AR-15 owners prefer to shoot with a prism scope instead of a red dot sight. 

Are prism scopes better?

For short and mid-range shooting, prism scopes are often better than other scopes. You don’t need a power source (because of the etched reticle), and the clarity is often sharper than other sights. 

What is the difference between a prism scope and red dot?

The difference between a prism scope and a red dot and why the former is often thought better is that a prism scope offers magnification, an illuminated reticle without battery power, and comes with a diopter.

However, a prism scope functions similarly to a red dot sight in that both options are used for short-range and tactical shooting.

Is an ACOG a prism scope?

Yes, some ACOG scope models use a prismatic scope for magnification and image clarity. However, not all ACOG scopes are prism scopes, as some come with variable zoom settings. 

How far can you shoot with a prism scope?

Typically, you can shoot up to 200 yards with a prism scope, but the distance depends on the magnification setting of the glass. 

Why are prism scopes better for astigmatism?

Prism scopes are better for astigmatism because they use an etched reticle instead of a projected red dot. So, it’s easier for shooters to see their focus point and, in some cases, may even fix astigmatism when firing. 

References

1. Collins Dictionary, telescopic sight. Retrieved from https://www.collinsdictionary.com/dictionary/english/telescopic-sight
2. Kate Kershner, What Are You Having: Roof Prism or Porro Prism Binoculars? Retrieved from https://electronics.howstuffworks.com/gadgets/high-tech-gadgets/binoculars-buying-guide1.htm