Do you spend a large amount of time looking through your binoculars? If you love looking at the night sky, bird watching, hunting, sightseeing, or hiking, you will likely spend more time looking through your binoculars than the average person! An important specification for binoculars is eye relief. So what is eye relief in binoculars? Read on to find out.
If this sounds like you, you need to consider what eye relief is on binoculars. If you often experience a fuzzy view from your binoculars, and you constantly have to readjust them to ensure you get a good view, then you will want to consider the eye relief as the problem!
Read on for more details surrounding eye relief in binoculars, including what it is and how it is useful!
What Is Eye Relief?
Eye relief is the fixed distance in the binoculars between the lens of the binoculars and your eyes. It refers to the perfect distance between the lens of the binocular and the tip of your eye.
In most cases, this distance should be around 15 to 18mm. If this distance is shorter or longer than this, then you may not get a clear view! A clear view refers to a bright and full view with no black ring and no fuzziness present!
If you don’t have this level of eye relief, you will not be able to get a good view of whatever it is you are looking at! If you are a bird watcher, you will be watching a very blurry bird.
If you are a traveler or an explorer, you will miss out on some beautiful sights. As a hunter, you might miss the perfect chance to catch your prey!
You wouldn’t be using binoculars if you didn’t want a good view, so eye relief is very important for any binocular users!
What Is Short Eye Relief?
If you feel like your eyes are straining, you are most likely suffering from short eye relief. This means that the distance between the binocular lens and the tip of your eye is much shorter than it should be.
In most cases, you will be using adjustable binoculars. If this is the case, you will need to adjust the distance, and this should resolve the problem.
If you are not using adjustable binoculars, then you may need to wear glasses.
Anything that is below 13mm counts as short eye relief. If you experience this, the image you see will appear fuzzy and have a dark edge.
What Is Long Eye Relief?
Long Eye Relief is when the distance between your eye and the lens of the binocular is longer than the fixed distance. If you wear glasses, then this is a common experience.
This is because the glasses will put some distance between your eye and the glass lens before you even start!
If you look through a pair of binoculars which have long eye relief, what you will see will appear cropped. Long eye relief is anywhere between 20mm and 24mm between your eye and the lens.
Eye Relief And Glasses
If you are someone who wears glasses, it is likely that you will want to use binoculars without removing your glasses. However, because the glasses will put some extra distance between your eye and the lens of the binoculars, this may affect the eye-relief measurement.
For those who wear glasses, the perfect eye relief would be around 16mm to 17mm. With this distance, those who wear glasses will be able to see the image through the binoculars very clearly.
You may need to adjust the eye cups on your binoculars if this does apply to you. You can also purchase some binoculars that come with shorter eye relief.
What Is The Difference Between Eye Relief And An Eyepiece?
The eyepiece refers to the lens you will look through when looking at an image. The eyepiece is fixed in place and will not be able to be moved.
Eye relief is the distance between the eyepiece and your eye. It refers to the perfect distance where you can see the full field of view. Eye relief can be adjusted using eyecups.
These are rubber cups that surround the eyepieces and help to keep your eyes at the right distance.
The eyepieces are located at the back of the binoculars. They are the last lenses in the optical path before the light will reach your eyes.
How Can You Check The Eye Relief?
You can check the eye relief on your binoculars in two ways. These include:
Check The Product Specifications
Most binoculars will have eye relief marked on the box of the product.
Measure The Distance
You can also measure the distance yourself. First, you will need to hold the binoculars at a comfortable distance and look through them. Then, as you move your eyes away from the eye pieces, you should measure the distance between your eyes and the eyepieces.
Tips For Proper Eye Relief
In order to get the proper eye relief on a pair of binoculars it is a good idea to purchase binoculars with varying eye relief. If you use adjustable binoculars, then you will be able to ensure that you are getting the best view through them.
If you wear glasses, then you will want to keep the eyecups in your binoculars as you are already placing some distance between your eye and the lens with the glasses.
If you don’t wear glasses, then you will want to twist the eyecups out when you are setting up your binoculars. This is because there is no extra space between your eye and the binocular lens.
Final Thoughts
Bad eye relief can have a negative effect on your binocular use. It can result in you missing out on your prey while hunting, or not being able to see some of the things you’re looking for while sightseeing. For astronomy, you may miss some wonderful vistas.
Bad eye relief can also cause injuries to your eyes if you end up straining too much. This can occur when your view is not clear.
Hi, my name is Jason Anderson, and I am a Physics Professor. Ever since I was a kid, I’ve been fascinated with space, the universe, the moon, you name it. I spent hours and hours at the planetarium close to my hometown, wondering what else could be out in the universe.
Since then, I’ve been an avid stargazer and astronomer, and love nothing more than spending my time charting stars, observing planets, and finding constellations.
This is why I decided to start Telescope Guru. I only wish to share this fun pastime with the world. With this site, I hope to answer all of your questions relating to astronomy, telescopes, and stargazing.
