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How to set IPD accurately? (1 Viewer)
- Thread starter tenex
- Start date
WJC
Well-known member
Go to your optometrist and have your IPD accurately measured. This measurement SHOULD be taken at the center of your pupils. But as long as it is taken at corresponding points on the eye, it doesn't matter.
Then, use a ruler or small steel scale to set the separation on corresponding points on your oculars to that setting. I say oculars. However, if separation is set by corresponding points on the eyecups, it's fine. IPD is IPD.
Finally, loosen the IPD scale and turn it to the separation you just created and tighten it down. Perfection is a LONG way from necessary. :cat:
Bill
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I'll add a tip to the good advice given above by Bill.
I have made plastic "rulers", or rather templates, that are exactly the length of my IPD, and can be carried in my wallet, pocket or binocular bag at all times. Mine are made out of disposable food container lids, but any material that you can cut with scissors and that preferably does not scratch the lenses if you are clumsy will suffice.
This simple little device significantly speeds up setting IPD, especially on binoculars that don't have scales on them.
Kimmo
I have made plastic "rulers", or rather templates, that are exactly the length of my IPD, and can be carried in my wallet, pocket or binocular bag at all times. Mine are made out of disposable food container lids, but any material that you can cut with scissors and that preferably does not scratch the lenses if you are clumsy will suffice.
This simple little device significantly speeds up setting IPD, especially on binoculars that don't have scales on them.
Kimmo
Bill's and Kimmo's suggestions are brilliant.
What I have found works for me and in recent years I have been able to check having got my IPD measured by my optician is to set the binos to where I can easily look through them and then alter the IPD until the fov is a perfect circle.
BTW opticians in the UK provide the IPD in the form of a measurement off-centre to each eye so you have to add the two together to get the full IPD so maybe this is standard around the world.
Lee
What I have found works for me and in recent years I have been able to check having got my IPD measured by my optician is to set the binos to where I can easily look through them and then alter the IPD until the fov is a perfect circle.
BTW opticians in the UK provide the IPD in the form of a measurement off-centre to each eye so you have to add the two together to get the full IPD so maybe this is standard around the world.
Lee
My wife often uses 'my' binos and she has a very different IPD, we carry a lot of gear on holiday and the trunk of our car gets full and sometimes during cramming things in the IPD of binos can get changed by accident, pocket binos get folded up so you need to reset your IPD every time, sometimes I cram a 32mm bino into a pocket by folding it up. Sometimes I close the binos up to get them into the case with the strap more easily. I have fairly narrow IPD and I find it easy to set it so I don't worry about having to do it.
Lee
WJC
Well-known member
That's not a Brit thing. It's a progressive lens thing. I once measured a lady who had one eye 3mm higher and 5mm farther from the nose than the other.
Precision opticians speak in terms of IPD.
Ophthalmic opticians speak in terms of PD. :cat:
Bill
WJC
Well-known member
My Canon 18x50 had neither the IPD or focus changed for about ten years.
But a friend wanted to look through it so they were changed.
I almost never change either now after resetting.
The only problem is the Eschenbach 4x? magnifying glasses.
I got them for £4 but they were filthy. They were about £80 new I think.
After cleaning I found I could not set the sliding IPD.
I must use a ruler to set the IPD here.
Just used the Eschenbach glasses and the view is good but very narrow.
Still the correct IPD.
A low vision aid I think.
I have never changed the focus or retuned my PST H alpha scope in over ten years.
But a friend wanted to look through it so they were changed.
I almost never change either now after resetting.
The only problem is the Eschenbach 4x? magnifying glasses.
I got them for £4 but they were filthy. They were about £80 new I think.
After cleaning I found I could not set the sliding IPD.
I must use a ruler to set the IPD here.
Just used the Eschenbach glasses and the view is good but very narrow.
Still the correct IPD.
A low vision aid I think.
I have never changed the focus or retuned my PST H alpha scope in over ten years.
tenex
reality-based
Thanks all! I'll have to get measured. It would be nice to know my pupil size too.
Already answered: sharing a glass with others, or possibly storing in a case. And even if you're a hermit and have a case that doesn't require folding flat (highly desirable) you have to set it up initially anyway, and an optimal setting will perform better especially when it gets darker. (By the way, I like your signature. Taking offense is a choice.)
Already answered: sharing a glass with others, or possibly storing in a case. And even if you're a hermit and have a case that doesn't require folding flat (highly desirable) you have to set it up initially anyway, and an optimal setting will perform better especially when it gets darker. (By the way, I like your signature. Taking offense is a choice.)
PeterPS
Well-Known Member
Measurements of the PD for each eye are standard in many other countries, the main reason being that the two PDs are not necessarily equal. An interesting question is how can you set the IPD of your binoculars if your PD1=33mm and PD2=37mm? IMO you would lose part of the FoV no matter how carefully the IPD setting was done.
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Hi Peter
Unless I am missing something here (quite likely) you would set your IPD to 70mm and when you lift the bins to your eyes, you would be looking perfectly down the optical axes of both tubes but the binos would be positioned to one side of the centre-line of your face. Why would you lose any field of view?
I should explain that we have just spent an hour and a half with our financial advisor so my brain is probably suffering from fatigue. :-O
Lee
PeterPS
Well-Known Member
Hi Lee,
If you set the IPD to 70mm then neither of your eye pupils will be aligned with the center of the EPs. The consequence is that you won't be able to see the right side of the field stop (assuming that the larger PD was for the right eye) and thus the FoV is reduced. If you align one of your eyes with one EP (by setting the IPD to either 66mm or 74mm) then you'll also miss the right side of the FoV, but a larger part of it than for the previous setting.
Peter
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Alexis Powell
Natural history enthusiast
No. Lee (Troubador) was right. The separate measurements for each eye are only relevant for eyeglasses because the lenses are held a certain distance and height from the bridge of the nose. Binoculars work fine when used with the hinge offset to the nose and one ocular a bit higher or lower than the other.
To answer the original question, I set IPD by looking through the bin and adjusting to minimize anything wrong with the view, both looking straight down the barrels and to each side. I've never had trouble doing this quickly and effectively, and I think it is the way most people adjust bins. Setting IPD according to measurements at the optician only works for those who only use bins at a great (or single) distance. Otherwise, it must be adjusted slightly for near versus far viewing, such as when viewing butterflies versus nearby sparrows/warblers vs. distant birds.
--AP
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tenex
reality-based
For measurement, I have a workaround for now: set up a bino with a much smaller EP (which is more precise for me) and measure the result. It's easier to go by edges than centers, as Bill pointed out. Then I can check or set the other one accordingly... and eventually perhaps learn to do it better directly, as Alexis suggested. I'm just not used to that yet.
Alexis Powell
Natural history enthusiast
I'd really like to understand your experience because I can't even imagine the problem relating to IPD. My face is not symmetrical so my lens centers for eyeglasses are adjusted accordingly. But the distance between my pupils is a straight line with a certain distance, so I have no trouble aligning each exit pupil and eye pupil when using binoculars.
I don't know what you mean by using one of the tubes to experiment. For example, with a bin with a single hinge, if you move one side it is equivalent to moving the other side. All you do is change the IPD. It can be correct, too wide, or too narrow. For a bin with two hinges, you can adjust the barrels individually relative to the focus knob, but again, it makes no difference except ergonomically. With the Leica 8x20 Ultravid, to quickly position the focus knob under my finger, I unfold one side all the way and the other side only enough to get proper IPD (see attached images). It has no importance for dealing with the asymmetry of my eyes, which is far less and perhaps not even in the same direction of deviation.
Perhaps the problem you have is with one or both eyes individually, fitting the eyecup to your face. For example, for someone with a large high nose and deep-set eyes that are very close set, a large diameter eyecup may bonk against the nose, preventing proper alignment of the exit pupil with eye. I wear glasses, so don't use the eyecups, so looking through two exit pupils that are my IPD apart is no different than looking through two holes punched in a piece of paper that are my IPD apart. As long as the holes are my IPD apart, it doesn't matter where you punch them in the sheet of paper, I can align my eyes!
--AP
Attachments
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dries1
Member
Ipd
No, it was this...
Conversation with financial advisor:
Lee. it has come to my attention regarding the depletion of XX% of your financial assets to binocular procurement. As your financial adviser, I highly recommend that you no longer purchase any binoculars, equipment, and materials, etc. from Zeiss.......You will now purchase all your products from Zenray Inc., until the balance sheet is back in the red...
Lee-
But.....Zenray?
Just kidding, on this Friday.
A.W.
No, it was this...
Conversation with financial advisor:
Lee. it has come to my attention regarding the depletion of XX% of your financial assets to binocular procurement. As your financial adviser, I highly recommend that you no longer purchase any binoculars, equipment, and materials, etc. from Zeiss.......You will now purchase all your products from Zenray Inc., until the balance sheet is back in the red...
Lee-
But.....Zenray?
Just kidding, on this Friday.
A.W.
