What is Scope Eye Relief, and How to Adjust Eye Relief on a Rifle Scope?

Ever been out on the hunt and lost sight of your target because your lens suddenly lost focus or was blurry? The unfocused image in your optics can be due to a number of reasons, but a significant one is known as eye relief.

This is a spec you need to know about, and if you ignore it, you better have a lot of band-aids on hand for your next shoot.

Eye relief is something very important to be considered when buying a rifle scope.

I thought I’d take some time to go over the concept of eye relief with the following goals:

• Try to define eye relief and provide a context about how it works
• Cover why is eye relief important question
• Discuss the process of adjusting the eye relief on a rifle scope.

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What is Scope Eye Relief?

Eye relief on rifle scopes is the distance between your eyes and the last lens within the eyepiece that allows for a clear, unobstructed image of the entire field of view.

Without eye relief, shooters wouldn’t be able to focus correctly when looking through a scope. In fact, it would be like trying to see a television with a resolution that doesn’t fit the screen – so no matter where you sit – the image would be all distorted and impossible to figure out.

Eye relief is normally measured in inches with rifle scopes, although there are a select few European based scope brands who provide eye relief in millimeters. Most eye relief measurements go from 4 to 100 millimeters or about 1 to 4 inches. The longer eye relief will definitely protect the shooter from receiving an unwanted cut or bruise.

The longest eye relief for an optical rifle scope is about 4 inches. This leaves enough room for the rifle to recoil and not strike you, if you have the proper ring mounts and the scope is mounted correctly.

The goal, when shooting long range, is to be as relaxed as possible, with your eye the ideal distance from the first lens.

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Why is eye relief important with scopes?

Many shooters grab their gun, mount their scope, and head out for a day of target practice without a second thought.

A few come back with bandages over their eyebrow.

Why?

Because they didn’t get their eye relief right. Spending some time getting acquainted with proper eye relief at the outset will save time and lower your risk for “scope eye.”

Scope eye occurs when your scope is mounted in such a way that you have to hunch up close for a clear field of view. If you get to close to your scope when using a powerful rifle, the recoil will cause your scope to smack into your eye.

If you have an optic handy, you can find out real quick why eye relief is so important. Take the item and hold it at arm’s length. Can you see anything besides a small dot at this range? Likely not. Now slowly bring it closer to your eye. 

Eventually, you will hit a point where the optic is full of light and picture. There will be no dark rings. Now bring it even closer. Again, you will see the picture start to shrink and a dark circle grow around the entire image.  

Proper eye relief gives you the biggest, clearest, and brightest picture possible. If the optic is too far or too close, the dreaded dark circles will form around your image. Now, you may be thinking you can simply hold the optic at proper eye relief and be done with it. 

Clipped images are another problem that comes from improper eye relief. This will shrink your effective FOV and degrades the picture quality of your scope. Which can cause some serious migraines and be very distracting.

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Now, let’s go over a few different things that eye relief helps with.

Image Quality

Most of the time, what you’ll see through a scope is the crosshair, and that’s it. The rest of the image will be so blurry that it would look as if the scope were damaged.

If you’re watching from too close, then the image will not only get blurry but dark. The rings around the scope will start eating the image away as well as the crosshair until the visuals are so small that you can barely see through it.

That’s why eye relief matters. Because it tells you what distance to watch from if you want the fullest and clearest picture possible.

High-Recoil Damage

Eye relief won’t only help to see through a scope well enough; it can also help to prevent high-caliber guns from causing damage.

If you have a .300 Remington Ultra-Magnum, then you’re likely to get tons of recoil. That means, once you shoot, the gun will push back towards your head. If you try to set your eye too close to the scope while shooting, then you may end up getting hurt.

How to Measure Eye Relief for a Scope

Eye relief is measured in inches or millimeters, and it’s mostly found in product descriptions and/or packages. A common low power rifle scope’s eye relief distance is 4 inches or 101.6 mm, which means that loss of image clarity will occur if one moves in closer or farther from it. The distance can vary between different brands and models of scopes. More eye relief is considered to be better in scopes.

 For example, magnum rifles have large recoils and therefore, require more eye relief for safe shooting.

Keeping in mind the need and requirement of the shooter, eye reliefs vary from scope to scope.

For example, your eye is normally dilated to 5 millimeters, and the exit pupil of your scope should match that measurement so that the diameter of the exit pupil on the scope and your eye pupil match.

When there is less light, your eye opens up to allow more light in, and this can cause a ring around the image in your scope. Basically, you should find the balance between being close enough to the scope in whatever light conditions you are hunting in to avoid the ring around the image, without actually being close enough to allow the recoil to impact the eye or the surrounding skin.

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What is a Good Eye Relief for a Rifle Scope?

When I’m scope shopping for myself, I typically won’t consider a rifle scope without a minimum of 3 inches of eye relief. Now if the glass is going on a shotgun for deer or on a higher-powered caliber, then I’ll usually increase my eye relief minimum to at least 4.5 inches. If the scope is going on something that really, really generates some recoil, then I’ll start looking for something in the 5 to 6 inch range.

Types of Eye Relief

It is not enough to know how eye relief works and how other features such as magnification & field of view affect it. You will also need to know about the different types out there if you want to get the most out of it.

Standard Eye Relief

The first type of eye relief, and the most common, is the standard eye relief.

The standard eye relief for most riflescopes between 3.5 and 4.5 inches – that would be around 50 mm to 110 mm. Is 3.5 inches. This measurement is a solid choice for most rimfire and standard centerfire rounds.

A standard eye relief works well with scopes with high magnification over 10x – so they’re pretty useful for long-range shooting. Of course, they also work with the most potent guns – such as Magnum rifles.

Standard is the most common option for guns at .308 and below, and is perfect for shooting across relatively flat terrain with mild recoiling rounds. 

Long Eye Relief

Long eye relief with a riflescope is right around 4.5 inches. This extra inch is to compensate for the heavy recoiling rounds.

These scopes are also great if you are going to take uphill shots. As you aim upwards, the space between your eye and the scope is diminished. They are perfect for calibers in the Magnum range, like the 300 Winchester Magnum. 

Longer Eye Relief  

Some scopes are designed to be both magnifying and used with powerful handguns. These extremely long scopes are sometimes called scout scopes, or handgun scopes. They are made for specific weapons and can have an eye relief of anywhere from 7 to 10 inches. 

They are popular on military surplus guns that feature open actions, which make mounting a standard or long scope challenging.

Аdјuѕtаblе Еуе Rеlіеf

For those who want extra viewing capacity without losing FOV or comfort, then an adjustable field of view may come in pretty handy.

But of course, adjustable eye relief comes at a price – it makes scopes a little heavier, a little harder to use, and often more expensive.

They usually work better with scopes at around 10x of magnification, but they also appear in all kinds of scope.

Ѕhоrt Еуе Rеlіеf

Then you’ll find short eye relief. It refers to all those that need no more than 125mm or 5-inches of total eye relief. And they can go as small as 13mm or 0.5-inches.

These aren’t adjustable and often demand you to get pretty close to the scope, which can be somewhat uncomfortable.

The Ѕhоrt Еуе Rеlіеf are not definitely bad, but they don’t offer the same advantages as adjustable or even standard eye relief offers.

What does “Short Eye Relief” mean?

A short eye relief would mean your eye needs to be closer and a large eye relief would mean your eye needs to be farther. If you’re too close than the proper eye relief, the image becomes blurry; if you’re too far, it becomes a tiny object in the center of the scope lens. A health hazard related to eye relief is that if your eye gets closer than the proper level, a rifle or firearm with greater recoil could make the scope slide back explosively when its shot, resulting in an injury to the shooter’s eye.

Eye Relief and Its Cousins

Eye relief doesn’t work by itself. As we explained in the above section, it relies heavily on many factors. Here, we’re going to explain two of them: magnification and field of view.

The Field of View (FOV).

This is the amount of distance you’ll see through a scope. For example, if you’re looking through a scoped rifle  at 100 yards away with a 10x magnification – then the field of view can be anywhere from 10 feet to 50 feet.

That amount of FOV will tell you how much you can see through the scope. The more FOV, the piece has, the more you’ll see around at such magnification.

Magnification

It is the power of a scope to get things closer through an image.

If a target is at 1,000 yards, then seeing it without scopes can be impossible. But if you have 20x of magnification, then you can see it as if it were at about 50 yards or even less.

Scope Mounting for Proper Eye Relief

This part gets a bit confusing as the eye relief on a scope is a fixed setting, so you have to actually move the scope either forward or backward in the ring or rings to adjust the eye relief to that specific shooter’s personal preferences.

I prefer to have the scope adjustment dials in the relative center of the scope tube precisely between the two mounting rings, but that is not always possible. When I mount my own scopes, I can build in some leeway on this by adjusting slightly how I might shoulder the rifle.

When you mount a rifle scope, before you tighten down the top half of the rings, the scope reticle crosshairs have to be squared to the rifle so there is no can’t. The scope also needs proper eye relief.

As most of the scope has no built-in eye relief. The user has to learn the adjustment.

So you left to adjust eye relief scope in order to find a comfortable and safe shooting position.

It’s a much more simple process than most people think. The eye relief of the scope when correctly set provides a more comfortable shooting experience. Allowing for faster more accurate shots downrange, or field.

The adjustment is all about fitting your neck length, buttstock length, shoulder thickness, and cheek shape – all these have to be in the position to allow you to keep your eye position properly.

There is some simple way to adjust the eye relief:

– You have to be sure about the distance of the rear scope ring. The ring has to be near the rifles eject port.

– Place the rifle scope in the rings and tighten loosely. Allow for the scope to slide slightly for adjustments.

– Make sure the lens cap is removed, and the magnification power is to be set in the highest number. The highest power setting will give the shortest view range.

– Mount the rifle on a stable platform facing a brightly colored well-lit wall.

– Your position affects the eye relief. Adjust the eye relief in a proper way so that you can put your position in a comfortable place.

– Shoulder the rifle and assume a comfortable shooting position. Avoid looking through the scope and focus on how it feels.

– Look through the scope and move it until you can see the entire FOV.

– Repeat as necessary until you find the most comfortable position.

– Level the riflescope and tighten the rings.

– Zero in the rifle scope.

The two main reasons for setting the correct eye relief:

First, to maximize the scope’s magnification view. This permits the shooter to see the widest, fullest field of view downrange without a dark circle around the inner circumference of the scope lens.

Second, without proper eye relief, the shooter risks the scope hitting the eye upon recoil.

To correctly adjust the eye relief of your rifle scope you will have to invest time. With the emphasis on not looking through the scope while finding a comfortable position.

This is because people will hunch their shoulders or contort their necks to obtain an entire FOV instead of focusing on their body position. Do not forget to sight in your rifle scope after mounting using the windage and elevation adjustment turrets.

Renowned writer, hunter, and optics specialist Ron Spomer shows how to properly mount a scope to fit you and your rifle for quick and precise aiming. These tips take the frustration out of scope sighting and will improve your shooting.

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What is a rifle scope eye relief extender?

The term eye relief extender is a little bit misleading as there really isn’t a way to extend the eye relief of a rifle scope beyond its factory settings.

Which part of the scope do I use for scope eye relief adjustment?

The scope itself does not have an eye relief adjustment that is built in.

The scope eye relief is adjusted by moving the rifle scope either closer to the shooters eye or farther away from the shooters eye. That adjusting movement takes place within the scope rings when the

scope is loosely positioned within the rings.

Conclusion

Eye relief is a simple concept and one you should certainly pay attention to because it determines how well you see your target. If you don’t fully understand the concept, you may end up screwing yourself over.

It might seem tedious to get your head around the nitty-gritty of the techs and specs, but the specs are important. It can determine if an optic is right for you, for your rifle, or for your needs.

As mentioned above, the distance of the eye and the scope eyepiece depends on the eye relief given by the product creator. However, the practical execution isn’t as simple as said. One cannot simply pre-decide an eye relief distance for a rifle scope. Before mounting a scope, you need to check its different models for different rifles, as the shoulder support for various stocks changes.

Still, picking the perfect eye relief is pretty tricky – so take your time. Don’t rush out without first knowing with certainty what you need and want.

We usually recommend trying a few scopes before going for your final choice. That would improve your overall experience in the end, and ensure that you’re sure of what you’re getting.

So, don’t let such a complicated feature keep you from buying a scope. Instead, use everything in this article and what you have learned from experience – and choose the right eye relief accordingly.

You won’t regret taking enough time when buying. A wise choice in this matter will make your shooting experience way better.

For Different Types of Rifle Scopes Check Our Guide:

How To Zero a Scope and Rifle? How Does a Rifle Scope Work? Best Scopes For .300 Win Mag Best Scopes with Red Dot Best Night Vision Scope Best Scopes For 308