Explained: What Is the Meaning of Eye Relief And Why Is It Important When Buying Binoculars?

  • By: Michaela King

If you’re in the market for binoculars, you might have heard of eye relief and may be scratching your head as to what is its meaning. In this article, we explain why eye relief is important when shopping for binoculars and why it’s the most important factor to consider when making your purchase decision.

Introduction to Eye Relief

Eye relief is the distance between your eye and the eyepiece lens of your binoculars. It’s important to have enough eye relief so that you can see the full field of view through your binoculars. If you don’t have enough eye relief, you’ll see a dark ring around the edge of your binocular’s field of view. This is called vignetting. The sweet spot is somewhere in between, where you can see the entire field of view without having to get too close to the binoculars.

Most binoculars have between 10 and 18mm of eye relief. If you wear glasses, you’ll need more eye relief so that you can see the full field of view. Some binoculars have special eyepieces that extend eye relief for people who wear glasses.

If you’re looking for a pair of binoculars for astronomy, it’s important to get a pair with at least 15mm of eye relief. This will allow you to see the full field of view without vignetting.

Factors such as magnification and objective lens size also come into play when deciding how much eye relief you need.

Different Types of Eye Relief

There are three different types of eye relief that you need to be aware of when shopping for binoculars.

The first is the minimum eye relief, which is the shortest distance your eye can be from the ocular lens and still see the entire field of view. This is important to consider if you wear glasses, as you’ll need to make sure there’s enough space between your eye and the lens to accommodate them.

The second type of eye relief is the apparent field of view, which is how much of the scene you can take in at once. This is affected by the size of the objective lenses and the magnification, so it’s something to keep in mind if you’re looking for a specific type of binoculars (e.g. birding binoculars vs hunting binoculars).

Finally, there’s the exit pupil, which is the size of the beam of light that reaches your eye. This is determined by the diameter of the objective lens and the magnification; a larger exit pupil means more light will reach your eye, making it easier to see in low-light conditions.

How Does Eye Relief Affect the Viewing Experience?

When you are looking through binoculars, your eyes should be relaxed and comfortable. If your eyes are not properly positioned in relation to the eyepieces, you will experience eye strain, which can lead to headaches and other problems. The distance between your eyes and the eyepieces is known as eye relief, and it is an important factor to consider when choosing binoculars.

Longer eye relief is generally better than shorter eye relief because it allows for a more comfortable viewing experience. However, there are trade-offs. Binoculars with longer eye relief tend to be heavier and more expensive. They also may have a smaller field of view. If you are unsure about what type of binoculars to buy, it is best to consult with an expert before making a purchase.

Also Read: How far can Binoculars see?

An example

Lets kick off with one of our favorites – the Vortex Optics Diamondback HD Binoculars

The eye relief on the 10 x 42 is a more than reasonable 15mm. 15mm of eye relief is usually enough for most applications. However, it is important to note that eye relief is subjective and will vary depending on the individual, the type of optics being used, and the specific application.

Also Read: Best spotting scope for eye glass wearers


In conclusion, now you understand the meaning of eye relief and its importance when choosing binoculars is key for ensuring that you are getting the most out of your purchase. Eye relief is an important factor to consider, as it will determine how comfortable you are when using the binoculars and ensure that you can get a clear view in any situation. With this knowledge in hand, finding a pair of binoculars with the perfect eye relief should be much easier.

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