Dioptre Setting: Fallacy and Fact (1 Viewer)

[Hauksen]

Hi Maljunulo,

I think the relaxed, unaccommodated (without arguing what that “means”) human eye will be focused on infinity.

A relaxed, unoccommodated eye is defined as an eye with the ciliary muscles which control the curvature of the OEM lens relaxed and in a state of zero contraction, so that the lens is at its minimum curvature.

Relying on wikipedia.de, I believe that's the original 1855 Helmholtz explanation, which since has been expanded (1980s-ish, it seems) by identifying some muscles that support accommodation towards infinity. I believe that would imply a finite (but long) distance for relaxed focussing, but the article only mentions this aspect in passing.

It seems that once you're a bit past 50 years, accomodation is limited to 2 dpt maximum, 1dpt typical, anyway (Duane's curve, via en.wikipedia.org). On one hand, that means that you're not likely to focus your optics to a distance much different from the optimum, but on the other hand, you're probably less able to tolerate deviations, I'd speculate.

Regards,

Henning

 

[Hauksen]

Hi Bill,

See the PDF attached.

Thanks a lot, I believe now I get it. (I'd suggest the explanation would be clearer without the emphasis on staring, but I'm not a native speaker.)

I'll give your method a try - I'm not sure I'll be able to spin the focus wheel fast enough to outrace my accommodation reflex, but if it works for other people, why shouldn't it work for me?

Regards,

Henning

 

[WJC]

Hi Bill,



Thanks a lot, I believe now I get it. (I'd suggest the explanation would be clearer without the emphasis on staring, but I'm not a native speaker.)

I'll give your method a try - I'm not sure I'll be able to spin the focus wheel fast enough to outrace my accommodation reflex, but if it works for other people, why shouldn't it work for me?

Regards,

Henning

Being able to Stare to relax without the brain pushing you along can take fiddling and wasting time out of the equation. However, I believe people should do as they wish. With most people not even knowing about the physiologic contributions. I though the whole thing was appropriate.

 

[Maljunulo]

It seems that once you're a bit past 50 years, accomodation is limited to 2 dpt maximum, 1dpt typical, anyway (Duane's curve, via en.wikipedia.org). On one hand, that means that you're not likely to focus your optics to a distance much different from the optimum, but on the other hand, you're probably less able to tolerate deviations, I'd speculate.
Henning

Henning;
Thank you for that, as I did not know Helmholz addressed that.

If one has had cataract surgery, and therefore has replacement implant lenses (as I have) one has, of course, zero accommodation.
Cheers!
Richard

It’s much easier to have a discussion if people define their terms and agree on a definition, which seems to be forgotten from time to time.

 

[WJC]

Henning;
Thank you for that, as I did not know Helmholz addressed that.

If one has had cataract surgery, and therefore has replacement implant lenses (as I have) one has, of course, zero accommodation.
Cheers!
Richard

It’s much easier to have a discussion if people define their terms and agree on a definition, which seems to be forgotten from time to time.

You mean like, "What is the BEST binocular for ....?

 

[WJC]

This stroke thing is really a pain! My first degree was in Journalism and Mass Communication. And I proofed that PDF more than once before I posted it. AND I just corrected about 15 errors. For gosh sakes it was only 2 pages!!!

 

[Hauksen]

Hi Bill,

This stroke thing is really a pain! My first degree was in Journalism and Mass Communication. And I proofed that PDF more than once before I posted it. AND I just corrected about 15 errors. For gosh sakes it was only 2 pages!!!

Very helpful anyway, I didn't actually notice any typos!

However, it just occured to me that the "problem fix" paragraph is a bit ambiguous with regard to the controls. I guess you're assuming that the diopter ring is on the left eyepiece, and the center focus is used to bring the right eye into focus, "without doing anything to the left mechanism" means leaving the diopter ring alone (since it would be too slow anyway).

This ambiguity had me confused for a bit at first, and I hope I have figured it out correctly. If not, please correct me!

Regards,

Henning

 

[WJC]

Hi Bill,



Very helpful anyway, I didn't actually notice any typos!

However, it just occured to me that the "problem fix" paragraph is a bit ambiguous with regard to the controls. I guess you're assuming that the diopter ring is on the left eyepiece, and the center focus is used to bring the right eye into focus, "without doing anything to the left mechanism" means leaving the diopter ring alone (since it would be too slow anyway).

This ambiguity had me confused for a bit at first, and I hope I have figured it out correctly. If not, please correct me!

Regards,

Henning

Just the opposite. The diopter ring is on the right side and the wheel brings the left EP in focus.

 

[Hauksen]

Hi Bill,

Just the opposite. The diopter ring is on the right side and the wheel brings the left EP in focus.

What's "the left mechanism" then? The central focus?

Regards,

Henning

 

[WJC]

Hi Bill,



What's "the left mechanism" then? The central focus?

Regards,

Henning

Yes.

 

[Steve C]

One time at our local big birding festival Swarovski was there with a booth during the introduction of the SV EL. The Swaro booth was right beside the booth being run by a dealer friend of mine. He also doubled as a Swaro field rep, but Clay Taylor was there for Swarovski that time as they were introducing the SV EL. The three of us were talking when an elderly lady stomped up to the Swaro booth, plunked down a Habicht 7x42 and demanded to know how much she needed to spend to get a binocular with a good image, and would one of these new whiz-bang wonders do the trick. Clay picked up the glass, askled her a couple of questions about her eye sight, turned the diopter wheel and asked her to try that. Well the lady was well and truly dumbfounded and immediately wanted to know what it was he did. He then gave her a lesson on focusing her binocular. He emphasized using a relaxed state rather than using stare, but that is what he meant. She had simply cranked the diopter wheel over all the way so it would not move, and just decided to leave it there since she had no idea what it was in the first place. Everybody knew you focused with the thing in the middle.

 

[Hauksen]

Hi Bill,

Yes.

Thanks!

So as I understand the procedure, it works like this:

• Set diopter knob to 0
• Prefocus binoculars on a distant target for left eye (both eyes open)
• Focus unaided left eye on a distant target (both eyes open)
• Raise binoculars quickly to both eyes (both eyes open)
• Quickly use centre focus to bring target into focus for right eye (both eyes open)
• Read dpt difference between both eyes off center focus wheel.

As my center focus wheels don't have a dpt scale, I suspect that's not quite right - maybe you could clarify?

Many thanks in advance!

Regards,

Henning

 

[WJC]

Hi Bill,



Thanks!

So as I understand the procedure, it works like this:

• Set diopter knob to 0
• Prefocus binoculars on a distant target for left eye (both eyes open)
• Focus unaided left eye on a distant target (both eyes open)
• Raise binoculars quickly to both eyes (both eyes open)
• Quickly use centre focus to bring target into focus for right eye (both eyes open)
• Read dpt difference between both eyes off center focus wheel.

As my center focus wheels don't have a dpt scale, I suspect that's not quite right - maybe you could clarify?

Many thanks in advance!

Regards,

Henning

— Set diopter knob to 0

No. Unless your At Rest dioptric setting is “0,” 0 has NO PLACE in the operation.

— Pre-focus binoculars on a distant target for left eye (both eyes open)

Preferably a mile or more.

Both eyes open would give you a step up on being relaxed, but it is not necessary.

You might want to de-focus quite a bit, and bring it to focus quickly. Remember, the brain is going to race you and if you are not diligent ... it will win. The more you practice this, the better you will get. But this should not be complicated, and if you have to make a lifestyle change, it’s not worth it. The point of the whole procedure is to make the experience more practical and pleasurable. Doing otherwise is just an effort in futility.

Now, DE-FOCUS the unaided left eye in the direction of that distant target preferably quite a bit.

— Raise binoculars quickly to both eyes (both eyes open, if you want)

You are now trying to get your target in as good a focus as you had before.

— Quickly use centre focus to bring target into focus for right eye.

No. If you use center focus wheel to “bring target into focus for right eye.” You will have just de-focused your left eye by THAT amount. (See the Attachment) While turning the right eye DIOPTER RING, you will be trying to reach the good focus you had in the left eye.

If your diopter ring was calibrated correctly at the factory, it will now give you the DIFFERENCE in diopters between your eyes.

— Read dpt difference between both eyes off center focus wheel.

No! If the center wheel has a diopter scale on it IT IS OF NO USE as it will change with EVERY new DISTANCE you try to view! There is only be ONE and it is on the right. Some people think their diopter setting is important to know. The information is misused much more than it is used correctly. I never use, or even think about, my diopter setting. I just focus the binocular and use it.

The point of all this verbiage is merely to let people know that the eye/brain combination is working against those who don’t know how to take physiological contributions out of the operation and will cause them to fiddle unnecessarily with their focus wasting time only to achieve a less that desirable image.

TRY TO BE RELAXED WHILE FOCUSING, left eye with the focus wheel and the right eye with the right eye adjustment which happens to be the diopter ring. When you establish your dioptric setting for each eye; forget about it you’ll live longer.

Finally, many to most people think their dioptric setting never changes. However, it may change slightly with fatigue, headaches, drugs (illicit or over the counter), too much water in the system, too little water, alcohol use, or caffeine ... etc.

— As my center focus wheels don't have a dpt scale, I suspect that's not quite right - maybe you could clarify?

Hopefully, you have only ONE focus wheel and it is not supposed to have one. As pointed out, having one there would be totally useless. As you get more used to binocular viewing, all this will become just part of you and will be no trouble at all.

DON’T OVER-THINK THIS! IT’S SUPPOSED TO BE FUN!

Many thanks in advance!

You are most certainly welcome.

Bill

P.S. the main character in the novel I’m working on has “Henning” as a last name.

 

[Trinovid]

I can't believe the mileage a thread on how use binoculars is getting, on a binocular forum no less! 🤣

 

[Binastro]

As to proof reading, I find that reading backwards, word by word from the end to the beginning is the most effective way of correcting typos.

As to setting up binoculars, I find that using real stars gives the best and most accurate results.

Distance terrestrial objects are full of clutter that confuse the situation.

Regards,
B.

 

[Tringa45]

I can't believe the mileage a thread on how use binoculars is getting, on a binocular forum no less! 🤣

No objections to an extensive discussion, but it surprises me too.
My original post was merely intended to remove a widely held misconception on dioptre setting.
To set the dioptre, which is simply a device to adjust the focus independently on the right barrel, whether on the right eyepiece or on the central hinge, choose a detailed high contrast object.
This could be a distant license plate or a TV screen (pixels) a few metres away.
Cover right objective and set focus.
Cover left objective and without disturbing the focus setting or altering object distance (if short and hand-held), adjust dioptre.
That's it.
The binocular will not allow an accuracy much better than 0,5 d, but when one considers that a focus range of 2 m to infinity on a 10x bin represents 50 d, I think that's good enough!

John

 

[Hauksen]

Hi Bill,

— Set diopter knob to 0

No. Unless your At Rest dioptric setting is “0,” 0 has NO PLACE in the operation.

Ah, thanks. Let me try again:

• Set diopter knob to approximately correct dpt values for your eyesight
• Raise binoculars
• Focus binoculars on a distant (>1.6 km) target for left eye
• Defocus binoculars a bit
• Focus binoculars for left eye, quickly
• Lower binoculars
• Focus unaided left eye on target
• Defocus unaided left eye quite a bit (>> 1.6 km)
• Raise binoculars quickly
• Use diopter ring to bring target into focus for right eye, quickly
• Read dpt difference between both eyes off diopter ring.

Does that look correct now?

P.S. the main character in the novel I’m working on has “Henning” as a last name.

Quite a remarkable coincedence, it's a fairly rare name! I don't think I've ever encountered it in any work of fiction I've read, so I'm thrilled to hear you're using it for a main character even!

Regards,

Henning

 

[WJC]

As to proof reading, I find that reading backwards, word by word from the end to the beginning is the most effective way of correcting typos.

As to setting up binoculars, I find that using real stars gives the best and most accurate results.

Distance terrestrial objects are full of clutter that confuse the situation.

Regards,
B.

Hi, B,

But it's much worse for me. Sometimes I will use the WRONG word. And when you're dealing with technical matters that's a critical difference. I have been known to leave as many as 3 words in a row out of a sentence. Then, I proof and proof proof know there will be those who seem to make a career out of trying to find fault with something I have said. Ed, Gijs, and Holger are welcome. Most of the others are just howling at the wind.

WJC

 

[Maljunulo]

I don’t understand why there is such confusion over simply adjusting for any difference between one’s two eyes which affects the focus setting.

A binoculars is, by definition, an instrument designed to be used with both eyes. If the two eyes differ sufficiently, it will be impossible to bring them to focus simultaneously.

The diopter adjusts one side of the binocular to match the other, as seen by that particular user. You set it once and forget it, as any difference between your two eyes is very unlikely to change.

it is not something you fiddle with.

 

[WJC]

I don’t understand why there is such confusion over simply adjusting for any difference between one’s two eyes which affects the focus setting.

A binoculars is, by definition, an instrument designed to be used with both eyes. If the two eyes differ sufficiently, it will be impossible to bring them to focus simultaneously.

The diopter adjusts one side of the binocular to match the other, as seen by that particular user. You set it once and forget it, as any difference between your two eyes is very unlikely to change.

it is not something you fiddle with.

John, Richard, and Trinovid,

I certainly agree that this has been blown WAY out of proportion. Nevertheless, it deals with an issue that is relevant and that most observers ignore. It bothers me not one whit. I know of the physiological issues in focusing, take them into consideration, focus the bino, and get on with life. But I am not all people.

But have you guys stood toe-to-toe, day after day, FOR 21 YEARS and tried to explain things to the needy observer who doesn’t have the capacity to comprehend what you are saying, regardless of how simply you presenting it? Correct me if I’m wrong, but I don’t believe you have. Just because this is a non-issue for you doesn’t mean it’s a non-issue for everyone. If you don’t “fiddle,” you are just dealing with a slight physiological involvement that doesn’t bother you. Congrats! It doesn’t bother ME in the least. But there are those who need to quantify ... EVERYTHING ... even if that quantification is all but meaningless. Yet, do these folks not deserve to understand?!

Fact 1: There are two dimension to focusing.
Fact 2: If the physiological contributions can be eliminated the observer is left in total control of focusing, reducing the NEED FOR SOME people to be constantly re-focusing their binocular except as the distance to the target changes.
Fact 3: Some of those who get wrapped around the axle worrying about their dioptric setting should not be. I understand it but see no reason to worry about it as those who need to quantify everything do.

Don’t shoot me; I’m just the piano player. And just because you and I understand this issue—or ignore it—doesn’t mean it is of no value to others.

PLEASE read the attached PDF.

And Hauksen: I have explained this so much, I have frustrated others. The concept is important to know but as Aristotle has so aptly put it:

“It ain’t THAT big a deal!”

I have to get on with other matters and move away from spending so much time on what, for most Birdforum members, is no more than trivia. So, please refer to post #26 and take your bino out and use it. You will come to understand.