You're fortunate the eye relief of the 8x30EII was sufficient for you, do you wear glasses/spectacles when using binoculars? I do, and I found with this binocular that if I looked through it with glasses its field of view was noticeably reduced; the example I tried would not focus sufficiently beyond infinity to allow me to use it without glasses either. I tried the MHG 8x42 at the UK Birdfair and had no issues - seemed like a typical 8x40 class binocular.
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Why is it such a common problem now days for binoculars to have too much eye relief r (1 Viewer)
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You're fortunate the eye relief of the 8x30EII was sufficient for you, do you wear glasses/spectacles when using binoculars? I do, and I found with this binocular that if I looked through it with glasses its field of view was noticeably reduced; the example I tried would not focus sufficiently beyond infinity to allow me to use it without glasses either. I tried the MHG 8x42 at the UK Birdfair and had no issues - seemed like a typical 8x40 class binocular.
Not done any ER measuring myeself, but a 19mm ER is totally impossible from the eye lens diameter and the specifed field of view. My user impressions and calculations suggest about 16mm is more likely.
David
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Pete Gamby also checked two units and verified the 19mm eye relief so perhaps what is at variance is the field of view.
Lee
Lee,
If the 19mm ER was correct then the FOV could be no more than an unimpressive 112.8m @ 1000m or 371ft@ 100yds if the magnification was correct. Otherwise a 6.9x magnification would make the other numbers work.
I don't think any spectacle wearers who have tried the Traveller ED would give 19mm ER much credibility.
I have another Opticron at the moment with an 'impossible' ER specification. The real value in this case is 2mm less than shown on their web site.
David
If the 19mm ER was correct then the FOV could be no more than an unimpressive 112.8m @ 1000m or 371ft@ 100yds if the magnification was correct. Otherwise a 6.9x magnification would make the other numbers work.
I don't think any spectacle wearers who have tried the Traveller ED would give 19mm ER much credibility.
I have another Opticron at the moment with an 'impossible' ER specification. The real value in this case is 2mm less than shown on their web site.
David
No, I don't wear glasses. The EII almost has too much eye relief for me but it is close enough.
That is more to the point. Well phrased.
I think you are on the right track there although I would change the phrase to: Why do so many eyecups not deliver the eye of so many users to the exit pupil.
Lee
Steve C
Well-known member
The length of the eye cup is not so much the issue here. The question I think should be "Why are there so few binoculars supplied with eye cups that do not extend to the specified eye relief distance?" Even then I wonder how much an issue it is.
Wow, that is about 35% deviation from spec!
JerryLogan
Well-known member
Patudo,
I finally reached the point where eyeglasses were necessary and was nearly crushed to find my EII FOV sharply reduced. The good news is that after 15 minutes of fiddling my old view was completely restored by turning the eyecups inside out and mounting then upside down on the binos. (Not sure if this is the same as just folding the eyecups down, but there was no way my cups would just fold over while mounted on the eyepiece. Hence, eyecups off, turned inside out and remounted on the binoculars.)
Hoping this might work for you as well.
Best,
Jerry
6-7mm would surely be TOO much. I really want 0 mm. I want the eye cups to touch my eye sockets for support or even be slightly pressing up against them. Which 4 binoculars had 6-7 mm?
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This was never a problem for me until a few years ago when my spectacle prescription changed slightly and I changed frame design too. Immediately, I had to extend the eyecups of my bins up from the fully screwed-down position by about 1.5mm, which was easy with some bins but needed o-rings to achieve with others. My latest specs also require this. The prescription change was small but maybe the frame design change was more significant but I can't see exactly what has caused this.
My point is that a minor change meant I passed over a line between 'fine and dandy' with the ER/eyecups on my binos to needing fiddling adjustments. It just goes to show that it doesn't take much for some folks to encounter an issue with ER/eyecups.
Lee
Steve C
Well-known member
I certainly agree that a minor change in specification can equate to a major change of use. I will turn 70 in a few months and even though I do not have need for anything other than non-prescription reading glasses at this point, I am well aware of the possibility that this may change in the future. As of now there are very few binoculars that give me any eye cup extension issues. Even with my non prescription reading glasses which tend to place my eye about 18 mm from the lens of the glasses, I can usually see the full fov.
I tend to be in agreement with Typo in that my experience with regard to his observation of the distance between the extended eye cup and the specified eye relief. I also see about the same variation in the 6-7 mm range as he states. Most eye cups extend upwards from the lens by 12-15 mm.
How all this will change for me waits for future developments and my inevitable drift into the need for prescription glasses.
wdc
Well-known member
Jerry, I'm wondering if you could post a photo of your workaround. If it means someone can see the whole FOV WITH glasses on in an EII, I'd like to learn how.
Thanks.
Bill
JerryLogan
Well-known member
I’ll give the photo a try and post tomorrow. It did restore the full field for me so there’s hope for some but, of course, YMMV. A good way to test if it’s going to work for you is to just pop the eye guards off and try the EII without anything between the eyepiece and your glasses. If you can find a position that yields a full FOV then it’s just a question of getting the eye guard end into that position. That’s how I found my approach to the problem.
Best,
Jerry
justabirdwatcher
Well-known member
Surely this cannot be as complex a problem as creating the optics themselves, or the coatings that go on them. Maybe it's an "optical vs. mechanical" engineer problem?
Steve C
Well-known member
I think it is an engineering vs bean counter problem. The less you put into something, the better the margin. But you are right I think in that it appears to be a simple solution.
I know what you mean but consider this.
Many eyecups work like an old draw-pull telescope don't they? I mean one tube fits inside another and just like you make the telescope longer by pulling one tube out from inside the other with eyecups this happens when you scew it or pull it out.
It seems as easy as falling off a log to make a longer tube possible by making both tubes a bit longer. But hang on, our eyecup needs to close down far enough to allow spectacle wearers to use it. So we can't just lengthen and lengthen the eyecup. We could do what the telescope makers do and make our telescoping eyecup out of 3 tubes. This would allow us to close it all the way down but still get a longer length when extended. Right?
No. Because to make 3 tubes fit inside each other means the eyecup needs to have a bigger diameter and at narrower interpupillary distances the fat eyecups won't fit around some fat noses so your binos will only accommodate a narrower IPD range.
And the bino maker might have already made the eyepieces as fat as he dare giving us both a decent eye relief and a great field of view. And which is sexier on the specs: a wide fov or telescoping eyecups?
I really can't see an easy solution here that will satisfy both spectacle wearers and non -specs wearers and all the variations in facial contours and spectacle lenses and frames.
Lee
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