Interpupillary Distance & Binoculars

interpupillary-distance

The question this week comes from someone who is looking to buy binoculars, but wants to make sure that they fit as they have close set eyes:

Have A Question For Me?Question:

I have never bought higher end bins so perhaps this is not an issue, but I don’t see any discussion in regard to my particular problem. Which is that I have close set eyes and the two lenses do not push close enough together for me to realize a proper single image. I am looking at bins in the $250.00 range. Your input is greatly appreciated, I have postponed buying bins because of my lack of knowledge and your work here is very helpful.


Answer

Thanks for the great question, interestingly I have received a number of similar questions to yours recently, so I have decided to publish my answer in the hope that it will help other readers as well:

Interpupillary Distance
Interpupillary distance adjustment on binocularsAs we all know, the distance between your eyes and in particular the centers of your pupils varies from person to person, in optics this is described as your Interpupillary Distance (IPD).

Why IPD is Important
It is important when looking through a pair of binoculars that the ocular lenses line up perfectly with your pupils, otherwise you get a dark halo forming around the image and only see a small part of the whole scene, which makes for a far than ideal view.

So because of this almost all binoculars have some sort of way to cater for our differences in IPD. Most use a hinge system between the two barrels allowing you to bring them, the eyecups and the ocular lenses closer or further apart. A few use a system where only the eyecup is moved, but this is usually to get around other design features, as is with the case with bins like the Canon IS Image Stabilized 10x30’s, where because of the electronics in the body, it is not possible to move the whole barrel.

IPD Distances

So how far apart are our eyes and how much does this vary from person to person. Well the best I could find were some results based on a US Military survey of Army Personnel conducted in 1988:

IPD values (mm)
Gender Sample
size
Avg Standard
deviation
Min Max Percentile
1st 5th 50th 95th 99th
Male 1771 64.7 3.7 52 78 57 59 65 71 74
Female 2205 62.3 3.6 52 76 55 57 62 69 71

So from this we can say that the average distance between the eyes of men in the US military in 1988 is just under 6.5cm, whilst for women it is just over 6.2cm. Where the smallest IPD was 5.2cm and the largest was 7.8cm. So lets assume that the average person on the street is fairly similar to those in the US Army… not that Hollywood would want you to believe it!

So how does this relate to binoculars?
Well firstly it is important to understand that not all binoculars are able to open or close the same amounts and not all will cover the maximum and minimum range based on the data above.

However rather frustratingly, not many manufacturers publicise the maximum and minimum distance that they can achieve, which makes it really hard to know which to choose if you are on one of the extremes, that is unless you go into a shop and try them for yourself.

If you are very worried about it (I’d don’t know how close set your eyes are) I would suggest opting for a compact binocular that has a duel hinge design (like the Opticron 10x28 Oasis below). The reason I say this is because of the double hinge, the barrels are able to close up far more than single hinge binoculars and some have a minimum IPD of less than 4cm which should cater for everyone. Other bins to look out for are the Leica and Steiner Compacts that also use this design.

For more on this, take a look at my article on the Best Compact Pocket Binoculars, that explains the double hinge design in more detail and lists some of the best.

I have also recently started recording the IPD distances on the pairs of optics that I am testing or reviewing and so below are some of the ones that I know about:

BBR Reviewed Bins with known IPD

To help you, the binoculars below are listed in order of their minimum IPD distance, with the closest ones listed first:

Opticron BGA T PC Oasis 10x28 BinocularsOpticron BGA T PC Oasis 10x28 Binoculars

IPD Max: 7.1cm
IPD Min: 3.6cm
Mid Priced Binoculars: ($130 – $300 / £130 – £300)

A duel hinged compact binocular, these are not only compact when using them, but can be folded into a really small shape, making them true pocket binoculars.

In my review of these Opticron binoculars, I thought that their optical performance was very good and that they compared very well with other far more expensive compacts.

 

Vanguard Orros 10x25 BinocularsVanguard Orros 10x25 Binoculars

IPD Max: 7.5cm
IPD Min: 4cm
Low Cost Binoculars: ($50 -$130 / £50 – £130)

These compact binoculars feature a unique offset hinge and focus wheel that not only gives them a very wide IPD range, but the minimum of only 4cm should easily accommodate those with eyes that are set very close together, which includes children.

Another benefit of the offset hinge on these great value low cost binoculars is that the position of the focus wheel means that depending on which hand you use, it is a little further way to reach for those with larger hands, but close with your left hand for those with smaller hands, making them ideal as adults and binoculars for children.

 

Swarovski CL Pocket 8x25 BinocularsSwarovski CL Pocket 8x25 Binoculars

IPD Max: 7.4cm
IPD Min: 5cm
High Value Binoculars: ($500 – $1200 / £500 – £1200)

Winner of the award for the best compact binocular of 2013, these compact Swarovski binoculars have my favorite duel hinge design that ensures they can fold up to a very small shape that means they will easily accommodate those with very narrow faces, but will also fit into your pocket.

As you would expect these come with a while host of the very best quality components and coatings that help them produce an image that is as good as it gets for a bin this size.

 

Kowa YF 8x30 BinocularsKowa YF 8x30 Binoculars

IPD Max: 7.2cm
IPD Min: 5.1cm
Low Cost Binoculars: ($50 -$130 / £50 – £130)

These mid-sized porro prism binoculars are very lightweight and have a very good minimum IPD. On top of this, they are fully water and fogproof, have fully multi-coated optics and a wide field of view.

A great value pair of binoculars that won my award for the best Low cost binocular in 2012, they make a great choice as binoculars for children or adults, especially those with smaller hands or close set eyes.

 

Swarovski EL 10x32 Swarovision BinocularsSwarovski EL 10x32 Binoculars

IPD Max: 7.4cm
IPD Min: 5.4cm
Very High Value Binoculars: (>$1200 / >£1200)

If you are looking for the very, very best binocular combined with a very impressive IPD range and one that will accommodate many with close-set eyes then look on further than these Swarovski EL Binoculars.

 

Hawke Nature-Trek 8x42 BinocularsHawke Nature-Trek 8x42 Binoculars

IPD Max: 7.2cm
IPD Min: 5.5cm
Low Cost Binoculars: ($50 -$130 / £50 – £130)

A single top hinge on these lightweight, roof prism binoculars, combined with a wide IPD range ensures that not only will these accommodate a wide spectrum of people, but will be comfortable and easy to use as well.

Considering their low cost, they also come with a surprising amount of high end features and components. The are fully multi-coated and have a nice wide field of view, making the ideal for anyone looking for a low cost binocular for birding, wildlife observation and general use.

 

Celestron Granite 8x42 BinocularsCelestron Granite 8x42 Binoculars

IPD Max: 7.3cm
IPD Min: 5.6cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

Winner of the Best Birding binocular on BBR in 2012, these 8x Celestron binoculars have an extremely wide field of view that is ideal for locking on and following a target like birds for example. The wide FOV is also great for scanning wide areas in search of something.

Made to a very high standard they have many high spec coatings, components and features including a lightweight open bridge magnesium body, fully multi-coated ED lenses and phase corrected Bak-4 roof prisms.

 

Celestron Granite 9x33 BinocularsCelestron Granite 9x33 Binoculars

IPD Max: 7.3cm
IPD Min: 5.6cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

With all the same high end features as their big brother (see above) these mid sized binoculars are ideal if you want a very high spec binocular that is just that bit smaller than a full sized one and all at a reasonable price.

The 9x magnification is a little different from the norm, but yet they still have a FOV wider than many 8x binoculars. These are well worth checking out.

 

Celestron Granite 9x33 BinocularsPentax 9x42 DCF BR Binoculars

IPD Max: 7.4cm
IPD Min: 5.6cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

When I tested these Pentax binoculars, I thought that they had a really great overall feel to them, both in terms of comfort and in they way they just ooze quality and good craftsmanship.

The 9x power on these is also a great for those who want a little more reach and image detail than you get with 8x, but do not want to sacrifice as much width in your view that you have to with most 10x bins.

 

Swarovski CL Companion 8x30 BinocularsSwarovski CL Companion 8x30 Binoculars

IPD Max: 7.4cm
IPD Min: 5.6cm
High Value Binoculars: ($500 – $1200 / £500 – £1200)

These sensational Swarovski binoculars are lightweight, compact and use some of the very best materials and coatings available.

This all ensures that perform to an extremely high level, combine this with their small size and you have a bin that is ideal for use in a wide range of areas, but especially travel and safaris. They are also ideal woman’s binoculars or indeed anyone with smaller hands and a narrow face.

 

Minox BL 8x44 HD BinocularsMinox BL 8x44 HD Binoculars

IPD Max: 8.0cm
IPD Min: 5.7cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

These premium made in Germany binoculars use excellent quality glass and coatings including Extra-Low Dispersion elements in their HD optical system. Combine this with their very wide field of view, great looking, robust and completely waterproof body and you have the ideal bird watching, hunting and general use binocular that cost much less than you would expect.

Their IDP range of 5.7cm to a whopping 8.0cm means that they will accommodate a very wide range of users.

 

Vanguard Spirit ED 8x42 BinocularsVanguard Spirit ED 8x42 Binoculars

IPD Max: 7.7cm
IPD Min: 5.7cm
Mid Priced Binoculars: ($130 – $300 / £130 – £300)

For a mid priced binocular to score an "outstanding" 83% on the BBR scale is excellent, but they achieved it partly because of the high quality image they produce which is made possible with features like fully multi-coated ED lenses and phase correction coatings on the high quality Bak-4 roof prisms.

What is more and just like the Endeavor below, you can currently get a $50 rebate on them in the US or a £20 cashback in the UK meaning they could cost you under $250 / £200. So it is no wonder that they are one of the best selling binoculars on this site.

 

Vanguard Endeavor ED 10x42 BinocularsVanguard Endeavor ED 10x42 Binoculars

IPD Max: 7.5cm
IPD Min: 5.7cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

Scoring an outstanding 85%, they were the BBR Winner for the Best Value for Money binocular in 2012. However these same Vanguard binoculars are now available at an even lower price than when I gave them the award! On top of this you can currently also get a $50 rebate on them in the US or a £20 cashback in the UK making them truly stunning value for money!

 

Opticron DBA Oasis S-Coat 8x42 BinocularsOpticron DBA Oasis S-Coat 8x42 Binoculars

IPD Max: 7.7cm
IPD Min: 5.7cm
High Value Binoculars: ($500 – $1200 / £500 – £1200)

A high quality 8x42 binocular from Opticron, with I describe their strong point as being the fact that they don’t have any major weak points! In my review I thought that the quality and brightness of the image produced was excellent and I also really liked the attention to detail with their quality accessories like the leather carry case, cleaning cloth and comfortable, well made neck strap.

 

Pentax DCF ED 8x43 BinocularsPentax DCF ED 8x43 Binoculars

IPD Max: 7.4cm
IPD Min: 5.8cm
High Value Binoculars: ($500 – $1200 / £500 – £1200)

Pentax Sport Optics flagship series includes this 8x43 binocular that combines the best quality optics and coatings, that includes aspherical lens with ED glass elements, phase corrected prisms and tough scratch resistant coatings with a lightweight magnesium body.

 

Minox BD 7x28 BinocularsMinox BD 7x28 Binoculars

IPD Max: 7.2cm
IPD Min: 5.8cm
Mid Priced Binoculars: ($130 – $300 / £130 – £300)

Fixed focus, lightweight compact binoculars, with a lower 7x magnification and wide field of view.

Ideal for quickly locking onto a subject as no focusing is required and the wide FOV makes target acquisition really simple. The low power also makes them easier to keep still and so would suit those with unsteady hands or for use on a moving platform like a boat or car.

 

Pentax DCF NV 8x36 BinocularsPentax DCF NV 8x36 Binoculars

IPD Max: 7.42cm
IPD Min: 5.9cm
Mid Priced Binoculars: ($130 – $300 / £130 – £300)

Large mid sized bins, or small full sized bins, these Pentax binoculars with their somewhat unique 36mm objectives come with Fully Multi-Coated Lenses, Phase Coated Bak-4 Roof Prisms and a high quality water and fog proof casing.

 

Hawke Frontier ED 8x43 BinocularsHawke Frontier ED 8x43 Binoculars

IPD Max: 7.5cm
IPD Min: 6.0cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

Open bridge binoculars with slightly larger than normal objective lenses that, combined with high end glass and coatings, help to produce a great quality and bright image.

 

Hawke Sapphire ED 8x42 BinocularsHawke Sapphire ED 8x42 Binoculars

IPD Max: 7.5cm
IPD Min: 6.0cm
Mid-High Value Binoculars: ($300 – $500 / £300 – £500)

Very high quality binoculars for this price range comes with many components and coatings like highly reflective Dielectric Prism Coatings that you only usually expect to find on higher priced optics.

 

For more take a look at the following:

I hope that some of these suggestions will help you make your decision. If you have any further questions related to this topic, please do not hesitate to ask in the comments section below

Have A Question For Me?Binocular or Optics Question?

If you have a similar or completely different binocular or optics related question that I have not already covered on BBR, then I would love to hear from you and do my best to answer if for you: ask your question here.

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