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Too much eye relief? (1 Viewer)

B

Bloodstriker

Well-known member
Since joining this site to research my first binocular purchase, I now own a small collection of bins. There's just something about optics that I like.

I have noticed one consistent complaint though. It seems as if the eye relief of every single binocular I won is too much. Another way of saying this is that the eye cups are too short.

I wear contact lenses, so I need the eye cups extended on all my bins. It seems the only bins that I can brace easily is the Conquest HD 10x42. And this is only because I have changed the eye cups to the extended replacements from Zeiss.

So far I've noticed this on my Euro HD 10x32, Terra ED 10x25, Pentax Papillio 2 8.5, Pentax AD 8x25 WP and to a lesser extent, Swarovski 10x25. I also experienced this while testing the Zeiss Victory SF 10x42, however it didn't happen with the HT 10x42. (Which is one of the reasons I am considering an HT above the SF for my next pair).

Does anyone else have this issue? If so, are there any aftermarket accessories that are made for correcting this? I've heard of using o-rings as a mod but I'm unsure as to where to begin.
 
I had one 8x42 Bushnell. The 10x42 did not do that. My eye area is such that I can rest the cups toward the top rather than jammed around the eye. Relieves some of the problem.
 
I know what you mean. I prefer to jam the whole cup into my eye socket area as I find that it has two advantages: 1. More stability as there's more contact with the face 2. Helps block out ambient light.

For most of my bins, I can usually rest the top of the eyecup on my brow, but I wish there was a better way
 
Bloodstriker said:
Since joining this site to research my first binocular purchase, I now own a small collection of bins. There's just something about optics that I like.

I have noticed one consistent complaint though. It seems as if the eye relief of every single binocular I won is too much. Another way of saying this is that the eye cups are too short.

I wear contact lenses, so I need the eye cups extended on all my bins. It seems the only bins that I can brace easily is the Conquest HD 10x42. And this is only because I have changed the eye cups to the extended replacements from Zeiss.

So far I've noticed this on my Euro HD 10x32, Terra ED 10x25, Pentax Papillio 2 8.5, Pentax AD 8x25 WP and to a lesser extent, Swarovski 10x25. I also experienced this while testing the Zeiss Victory SF 10x42, however it didn't happen with the HT 10x42. (Which is one of the reasons I am considering an HT above the SF for my next pair).

Does anyone else have this issue? If so, are there any aftermarket accessories that are made for correcting this? I've heard of using o-rings as a mod but I'm unsure as to where to begin.
Click to expand...

Unfortunately the o-ring trick only works for spectacle wearers. You unscrew the eyecups (assuming they are the type that remove for cleaning and this should be in your user instructions) and slip an o-ring or part of an o-ring underneath then screw the eyecup down. It hits the o-ring and hey presto it is now sitting higher than before.

But for non-spectacle wearers this isn't an option and I haven't come across any aftermarket accessories to help. Sorry.

This might sound daft but you might be just as well wearing specs for your birding. If you have a pair from before you started wearing contacts, or even just a pair of sunglasses, you could try it out.

Good luck.

Lee
 
pshute said:
What's the problem with too much relief? What are the symptoms? Do you get blackouts?
Click to expand...

The OP will no doubt answer for himself but it is worth reminding ourselves that what is here being called 'too much relief' is actually a symptom of the eyecups being too short when in combination with the OP's facial structure, so that the eyes aren't delivered to the exit pupil at a point where the full field of view can be seen. The eye relief is a consequence of the design of the optical system so it is misleading to think of it as being too much. The fact is that eyecup design and size is a compromise to fit as many facial structures as practical and they won't fit every single person.

Lee
 
I imagine you only need to extend the eyecups just a little more than they presently go. I wear glasses, so I haven't delt with this myself, but I've seen people fashion extensions from pieces of bicycle innertube or similar, or you might be able to adapt one of the aftermarket winged eyecup extensions, or the aftermarket eyecups sold for astronomy eyepieces.

--AP
 
Alexis Powell said:
I imagine you only need to extend the eyecups just a little more than they presently go. I wear glasses, so I haven't delt with this myself, but I've seen people fashion extensions from pieces of bicycle innertube or similar, or you might be able to adapt one of the aftermarket winged eyecup extensions, or the aftermarket eyecups sold for astronomy eyepieces.

--AP
Click to expand...

This is worth a try - thank you.

Yes, I do need to extend the eyecups somehow as they aren't long enough for me on most binoculars. I wind up getting blackout if I don't brace them against my brow.
 
Most modern binoculars have too much eye relief for me.
This gives great loss of stability, because the binocular is not held firmly, it just wobbles.
Plus sometimes blackouts.

Why aren't there binoculars for non eyeglass wearers?
Why should I wear glasses, giving loss of transmission, extra CA etc. when I don't need them?

The Zeiss 5x10T is useless unless I wear my distance glasses and have it touching the monocular.
 
Binastro said:
Most modern binoculars have too much eye relief for me.
This gives great loss of stability, because the binocular is not held firmly, it just wobbles.
Plus sometimes blackouts.

Why aren't there binoculars for non eyeglass wearers?
Why should I wear glasses, giving loss of transmission, extra CA etc. when I don't need them?

The Zeiss 5x10T is useless unless I wear my distance glasses and have it touching the monocular.
Click to expand...

I also have a 5x10T monocular as well and found that there's a simple trick to using them without glasses. Simply curl up your hand with your index and thumb touching, and use this as a makeshift eyecup. Now brace your and right up against your eye, while holding the monocular in the same hand and adjust for the proper eye relief distance. Works very well for me.
 
Lee,
Yes there are binoculars for non eyeglass wearers, but many have too short eyecups, and especially, miserably small fields.
Also my glasses gives a colour shift.

Bloodstriker.
I do use the 5x10T in the way you describe, but it is steadier against the distance glasses.
 
Alexis Powell said:
I imagine you only need to extend the eyecups just a little more than they presently go. I wear glasses, so I haven't delt with this myself, but I've seen people fashion extensions from pieces of bicycle innertube or similar, or you might be able to adapt one of the aftermarket winged eyecup extensions, or the aftermarket eyecups sold for astronomy eyepieces.
Click to expand...

Bloodstriker

1. To expand upon Alexis' post, I attach a photo of a binocular that has had its eyecups extended by the use of doubled-over bicycle inner tube.

In fact I used two lengths of inner tube of different section. I can't remember why. But looking at the photo, it was probably in order to achieve a greater extension without the outer rim of the extended part contracting too far inwards.

IGNORE MOST OF WHAT FOLLOWS IF YOU ARE A CYCLIST!

2. There are two variables to consider when seeking out gash bicycle inner tubes to use for extending eyecups (or adding wings to them):
* The section of the tube in inches or millimeters
* The thickness of the tube wall: normal; thick and stiffer; thin and stretchier.

To dispose quickly of the relevance of 'thickness', a stretchier tube is easier to fit, so making the operation of sleeving it over the eyecup less likely to damage the binocular.

I don't go into the complex world of the calculation of tyre and inner tube 'sections', and how far manufacturers do correctly report them. I don't need to because for comparative purposes, sections can be taken to reflect diameters.

Inner tubes are labelled with the specification of the type of tyres, and range of tyre sections, that they are intended to be used with, eg:

26x1.9/2.125: Mountain bike tyre of 26in diameter, 19in to 2.125in section

700x28/37: Road bike tyre of 700mm diameter, 28 to 37mm section

[The dimensions are given in inches or millimeters supposedly according to the original dominance of mountain bikes in the US market, and road bikes in the European market.]

3. What you will be looking for is the maximum tyre section, namely in the above two examples: 2.125in or 37mm.

Depending upon the diameter of the eyecups of your binocular, you'll probably start trying a mountain bike inner tube intended to fit a tyre of maximum 2.125in section. Certainly in Britain, tubes of the sort are some of the commonest ones that are available.

From there on, if the diameters of the binocular eyecups that you wish to extend are like the diameters of the eyecups that I have extended, you will ideally seek to have by you a selection of gash inner tubes of progressively greater section.

Unfortunately, where I live I have found such inner tubes more and more difficult with each increase of section to find.

4. I continue to use inner tubes on my bicycles with five or more patches. None of the tyres on my bikes goes much over 2 inches in section. So my main source of inner tubes is two local bike shops.

Even if I am given a tube intact, I should mention that I still in courtesy cut it in the shop in order to render it irrepairable.

For practical reasons, and for reasons of legal liability, when a bicycle shop repairs a puncture for a customer, they throw away the old inner tube, and fit a new inner tube. The supply of new inner tubes--and more broadly, the non-return to the market of repairable old tubes--is thus commercially an important part of their business.

5. Hoping what I say is helpful!


Stephen
 

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Stephen Prower said:
Bloodstriker

1. To expand upon Alexis' post, I attach a photo of a binocular that has had its eyecups extended by the use of doubled-over bicycle inner tube.

In fact I used two lengths of inner tube of different section. I can't remember why. But looking at the photo, it was probably in order to achieve a greater extension without the outer rim of the extended part contracting too far inwards.

IGNORE MOST OF WHAT FOLLOWS IF YOU ARE A CYCLIST!

2. There are two variables to consider when seeking out gash bicycle inner tubes to use for extending eyecups (or adding wings to them):
* The section of the tube in inches or millimeters
* The thickness of the tube wall: normal; thick and stiffer; thin and stretchier.

To dispose quickly of the relevance of 'thickness', a stretchier tube is easier to fit, so making the operation of sleeving it over the eyecup less likely to damage the binocular.

I don't go into the complex world of the calculation of tyre and inner tube 'sections', and how far manufacturers do correctly report them. I don't need to because for comparative purposes, sections can be taken to reflect diameters.

Inner tubes are labelled with the specification of the type of tyres, and range of tyre sections, that they are intended to be used with, eg:

26x1.9/2.125: Mountain bike tyre of 26in diameter, 19in to 2.125in section

700x28/37: Road bike tyre of 700mm diameter, 28 to 37mm section

[The dimensions are given in inches or millimeters supposedly according to the original dominance of mountain bikes in the US market, and road bikes in the European market.]

3. What you will be looking for is the maximum tyre section, namely in the above two examples: 2.125in or 37mm.

Depending upon the diameter of the eyecups of your binocular, you'll probably start trying a mountain bike inner tube intended to fit a tyre of maximum 2.125in section. Certainly in Britain, tubes of the sort are some of the commonest ones that are available.

From there on, if the diameters of the binocular eyecups that you wish to extend are like the diameters of the eyecups that I have extended, you will ideally seek to have by you a selection of gash inner tubes of progressively greater section.

Unfortunately, where I live I have found such inner tubes more and more difficult with each increase of section to find.

4. I continue to use inner tubes on my bicycles with five or more patches. None of the tyres on my bikes goes much over 2 inches in section. So my main source of inner tubes is two local bike shops.

Even if I am given a tube intact, I should mention that I still in courtesy cut it in the shop in order to render it irrepairable.

For practical reasons, and for reasons of legal liability, when a bicycle shop repairs a puncture for a customer, they throw away the old inner tube, and fit a new inner tube. The supply of new inner tubes--and more broadly, the non-return to the market of repairable old tubes--is thus commercially an important part of their business.

5. Hoping what I say is helpful!


Stephen
Click to expand...

Thank you Stephen. This is pretty much what I'm looking for!
 
Stephen, I do have question for you.

You mention that I might want to start with 2.125in or 37mm. I measured the diameter of my eyecups, and they are approximately 1.5in in diameter. Would I look for something just slightly bigger than 1.5"?
 
Bloodstriker

1. Don't mind if I correct you! Tyre and Inner tube sizing can be a minefield for cyclists, let alone non-cyclists.

Thus 2.125in converts to 54mm, not 37mm. My two examples of tyre sizes, the one expressed in inches, and the other in millimetres, were not meant to be equivalent!

2. As to your question, you are half in luck, because one of my cheap binocular punts has roughly 1.5in diameter eyecups.

You are half out of luck, because I don't have a length of inner tube that fits them. I have a length marked 27.5x2.10/2.35 that is a tight, probably too tight, fit. And my next size up is a monster 26x2.3/3.0, which is way oversize.

3. Remember I don't know whether the 'section' measurement of a bicycle tyre actually represents 'diameter'. The things aren't perfectly round. And they change shape further when inflated.

And I also don't know how the diameter of an uninflated inner tube relates to the range of 'section' measurements of the tyre that it is intended to fit.

The main thing is that the diameter of an uninflated inner tube, in relative terms. is likely to rise with the figure of the maximum 'section' of the size of tyre that it is intended to fit.

So I have my selection of gash inner tubes, and try different sizes, up a little, or down a little, until I get a good fit.

4. You, by contrast, understandably want to get it right first time.

A bit of stretch does no harm, so I would reckon that you're looking for a discarded mountain bike inner tube marked with a maximum figure of the section of the tyre that it is intended to fit of 2.4 to 2.5in.

Don't worry about road bike tyres sized in millimetres! I'd say a figure of 40mm section is the highest that you are likely to find for them. That converts to just 1.6in.

5. While I write, it's coming back to me as a possible tip that, if you have two lengths of inner tube, one slightly too tight, and the other slightly too loose, you can sleeve the first, either not doubled up, or doubled up, over the eyecup up to the level of the top of the eyecup, and the second may then sleeve as a good fit over it to give you the extension that you desire.

Thus the problem with a tight fitting length of inner tube is that, once it is no longer supported by the side of the eyecup, it will curl inwards over the eyepiece lens. But this doesn't apply when it is used merely to bulk out the diameter of the eyecup.


Stephen


I didn't say in my previous message what sort of extension you can expect to achieve. I've only gone for extensions up to about 4mm. I would think that 'curl over' is likely to be a limiting factor for figures much greater than this.

Also the eyepiece designer does not contemplate persons extending his or her eyepieces, so that you are by then seriously entering unexplored territory!
 
Bloodstriker

I separately correct an error in my first post. The extension in the photo is in fact achieved by a single sleeve of doubled-over inner tube.

I was misled by the resemblance of the appearance of the top of the eyecup at a quick glance to the top of a second sleeve of doubled-over tube.

Stephen
 
I have this problem also. I don't understand why someone said the o-ring trick does not work for non-eyeglass wearers. It works fine for me. Just unscrew the eyecups, put an o-ring on the threads, then screw the eyecup back on.

Of course this only works if you only need a small amount more distance. With my Zeiss Conquests, i had to get the extended eyecups and also use o-rings.

It does suck that we have to live with binos that are much longer than advertised.
 
PeteQuad said:
I have this problem also. I don't understand why someone said the o-ring trick does not work for non-eyeglass wearers. It works fine for me. Just unscrew the eyecups, put an o-ring on the threads, then screw the eyecup back on.

Of course this only works if you only need a small amount more distance. With my Zeiss Conquests, i had to get the extended eyecups and also use o-rings.

It does suck that we have to live with binos that are much longer than advertised.
Click to expand...

Hi Pete

It was me that said this doesn't work for non-eyeglass wearers. I couldn't imagine the eyecups being secure in their new position. Its great to hear that it can work this way too :t:

Lee
 
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