• BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

    Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Bino Thoughts #7 (1 Viewer)

WJC

Well-known member
201101

Sorry to have so many of these bunching up. But I am going to try to get this one taken on by a higher-order publication and I would appreciate it if those who like to pick at me would be so good as to save me from myself. Since the stroke, the fingers are reluctant to work on command. :cat:

Bill
 

Attachments

  • BF STARING 201101 .pdf
    121.5 KB · Views: 95

eronald

Well-known member
201101

Sorry to have so many of these bunching up. But I am going to try to get this one taken on by a higher-order publication and I would appreciate it if those who like to pick at me would be so good as to save me from myself. Since the stroke, the fingers are reluctant to work on command. :cat:

Bill

Now if you could just tell me why in the space of a year the difference in diopter adjstment between my eyes on my Leica UV HD has gone from over 4 to 1.5 marks on the wheel.

I'm seeing the eye doctor next week.
 

WJC

Well-known member
Now if you could just tell me why in the space of a year the difference in diopter adjstment between my eyes on my Leica UV HD has gone from over 4 to 1.5 marks on the wheel.

I'm seeing the eye doctor next week.

Hi, Edmond,

That would be a question for an ophthalmologist.

However, the following two sentences should be popped into Bino Thoughts #7 directly before "LEARNING to STARE." :cat:

BILL
 

Tringa45

Well-known member
Europe
Hi Bill,

Sorry, but I have to disagree with you on two counts.
Firstly, I think the method you describe is not very precise, and secondly the distance of the object you use to set the diopter is absolutely immaterial.
When we view an object with a telescope or binocular we set the focus so that its image appears at or near infinity, i.e. the image formed by the objective is in or near the focal plane of the ocular. The myopic would, without glasses, place this image slightly inside the focal plane so that rays emanating from the eyepiece would diverge. Conversely, the far sighted would place the image outside the focal plane so that rays from the eyepiece would converge. The actual distance of the object from the binocular doesn't matter because its focussed image is always in the same place.

To verify this concept I have just performed an experiment under fairly critical conditions. I think I am even your senior (see my nick :-() and have very little accommodation in my right eye and none in my left after cataract surgery. I used a 10x binocular (a 10x42 Swarovski SV), which has a shallow depth of field on a tripod.
Swarovski roof prism binoculars have a very stable diopter setting due to the spring-loading of the focussing elements.
With the right objective covered, I focussed on the branches of a tree 115 m distant and then retracted the focussing knob to disengage the left barrel and displaced it to an arbitrary setting before adjusting the diopter with the left objective covered. The diopter was on zero and I repeated the the procedure indoors at a distance of 2 m to end up at zero again. This was with my glasses on and a second test without them resulted in +2 diopters at 115 m and 2 m.

Old eyes are almost always a handicap but in this case the lack of accommodation aided the repeatability. I wouldn't necessarily suggest that younger observers go to these lengths, merely that they choose an object with fine detail at any distance to set the diopter.

John

PS:- I hope you soon recover your original dexterity.
 

WJC

Well-known member
Hi Bill,

Sorry, but I have to disagree with you on two counts.
Firstly, I think the method you describe is not very precise, and secondly the distance of the object you use to set the diopter is absolutely immaterial.
When we view an object with a telescope or binocular we set the focus so that its image appears at or near infinity, i.e. the image formed by the objective is in or near the focal plane of the ocular. The myopic would, without glasses, place this image slightly inside the focal plane so that rays emanating from the eyepiece would diverge. Conversely, the far sighted would place the image outside the focal plane so that rays from the eyepiece would converge. The actual distance of the object from the binocular doesn't matter because its focussed image is always in the same place.

To verify this concept I have just performed an experiment under fairly critical conditions. I think I am even your senior (see my nick :-() and have very little accommodation in my right eye and none in my left after cataract surgery. I used a 10x binocular (a 10x42 Swarovski SV), which has a shallow depth of field on a tripod.
Swarovski roof prism binoculars have a very stable diopter setting due to the spring-loading of the focussing elements.
With the right objective covered, I focussed on the branches of a tree 115 m distant and then retracted the focussing knob to disengage the left barrel and displaced it to an arbitrary setting before adjusting the diopter with the left objective covered. The diopter was on zero and I repeated the the procedure indoors at a distance of 2 m to end up at zero again. This was with my glasses on and a second test without them resulted in +2 diopters at 115 m and 2 m.

Old eyes are almost always a handicap but in this case the lack of accommodation aided the repeatability. I wouldn't necessarily suggest that younger observers go to these lengths, merely that they choose an object with fine detail at any distance to set the diopter.

John

PS:- I hope you soon recover your original dexterity.

Hi, John,

I sure wish others wanting to dispute something I have said, or take me to task, could do so as courteously.

Sorry, but I have to disagree with you on two counts.

— Firstly, I think the method you describe is not very precise ...


The brain does not work with the mathematical precision that can only be replicated on a computer screen. Thus, the “precision” is only as accurate and relevant as the individual OBSERVER’S ABILITY to control his or her focus by staring. This is an individual matter. And, what could be more precise for an observer than his or her own focus?

The screenshot attached is the spot diagram of a Houghton telescope I designed 18 years ago. On axis the visual wavelengths look like a pea laying in the center of a plate, that plate representing the Airy Disk. Even at the edge of a 1.5-degree field, the visible wavelengths are well within the disk. I performed this operation just to see what I could do.

Science and medicine have shown that a star image (or other pinpoint) that falls within the Airy Disk can’t be recognized from “perfect” by the eye/brain companionship. Pretty good designing for a little kid ... huh? My Image didn’t just fall within it; it fell within a FRACTION of it. * That was calculated BB stacking on my part. So, how much computer-generated precision can the eye/brain companionship really resolve?

— and secondly the distance of the object you use to set the diopter is absolutely immaterial.

As you say, “sorry.” Your comment is as intuitive as it is wrong.

With both eyes open, an observer will be trying to focus one telescope with background stimuli from the other telescope getting involved, and this could be from efforts at spatial accommodation, no matter how slight. The greater this distance the less of a factor this will be, and it is the misleading effects of background stimuli that neurologist and Visual Science professor, Dr. Edward Adelson, of MIT has worked so hard at showing that what we THINK we see ... we often don’t. This, of course, would not be an issue if using the "cover-the-objective" techniques. But, remember, I'm trying to teach people to stare, which is more useful in the long run.

I hope you understand my rationale. If you don’t, please let us agree to disagree, agreeably.

PS Thank you for your well-wishes. I offer you the same! When I was in my 20s, I could have sworn getting older took a lot longer. ‘Guess not. The artifacts from my stroke are getting worse. I fell in the garden twice last week while trying to get as many tomatoes in as I could before the frost.

About 10 years ago, I decided I was going to live forever and ... SO FAR, SO GOOD! :cat:

Cheers,

Bill
 

Attachments

  • scan0003 (2) copy 2.jpg
    scan0003 (2) copy 2.jpg
    128.2 KB · Views: 45
Last edited:

Omid

Well-known member
United States
{A} When we view an object with a telescope or binocular we set the focus so that its image appears at or near infinity, i.e. the image formed by the objective is in or near the focal plane of the ocular.

{B} The myopic would, without glasses, place this image slightly inside the focal plane so that rays emanating from the eyepiece would diverge.

{C} Conversely, the far sighted would place the image outside the focal plane so that rays from the eyepiece would converge.


John

John,

What you have mentioned above seems very logical but it is not how it happens in reality. In reality, people with very good eyes also focus their instrument such that the image is at a finite distance. That is, the people in {A} also act as if they are myopic {B}!!

See my posts #210, #211 and #215 under my personal thread called "New Horizons II":

https://www.birdforum.net/showthread.php?t=378895&page=9


--Long post with so many unrelated material --

Bill

Bill,

It would be more productive if you could answer John's objection/comments more clearly using less words. To help John understand what you are saying I will try to summarize your point: If I understand correctly, Bill believes it will help an observer when focusing his binoculars if he stares at a far away object first and then bring up the binoculars quickly and turn the focus wheel to achieve focus. This method can help prevent eye accommodation and manual focusing of the binocular race against each other.

We discussed Bill's idea once before. See my posts #10 and #16 here:

https://www.birdforum.net/showthread.php?t=390836

----

Now I disappear back to my invisible sphere and let you two senior gentlemen continue your discussion ;)

Omid
 
Last edited:

Tringa45

Well-known member
Europe
Bill & Omid,

First off, Bill, I think you misunderstood me. I was not suggesting that one try to set the diopter with both eyes open. In my experiment, which conclusively showed the irrelevance of object distance, I successively obscured one barrel with an objective cover. For most it would probably be quite adequate to follow the procedure: close right eye and set focus, close left eye and set diopter.

Perhaps you will allow me an unaccustomed digression, and I'm sure, Bill, that you will indulge me ;).
The German transport minister is strongly influenced by the automobile lobby and during the Diesel scandal eagerly jumped on the bandwagon of an emeritus professor for lung diseases. The professor was of the opinion that the EU limitations for NOx in (city) air of 40 µg/cu. m were far too stringent and that these levels should be relaxed. In some of his analogies he had miscalculated by several orders of magnitude and on a TV show he even asserted that the "air" that comes out of the exhaust of a modern Diesel is cleaner than what goes in! This showed a complete ignorance of how an internal combution engine works and that he had forgotten all his school chemistry to boot.

What I am trying to say here is that people are far too vulnerable to the opinions of "experts" who express themselves on topics which have no or only a peripheral relationship to their own speciality. Did the researchers quoted by Omid have sufficient data to calculate the virtual image distance of an observer and do they understand the workings af a Keplerian telescope?

Here is a simplified drawing from Wikipedia: https://en.wikipedia.org/wiki/Refracting_telescope#/media/File:Kepschem.png. Note that the rays emanating from the eyepiece are PARALLEL and that the virtual image is at INFINITY. A minor error is that the second distance labelled f2 on the right is eye relief and not the eyepiece focal length.

John
 

Omid

Well-known member
United States
Hi John,

I agree with you that we should not blindly accept the opinion of experts especially if they are talking outside their field of expertise. Now, regarding the research results I quoted, there are multiple studies on this topic accumulated across a broad time span (from 1950s till now). Since this is Bill's topic and should be dedicated to discussion of "his paper", I'll continue the topic of instrument myopia in my own thread.

Sincerely,
-Omid
 
Last edited:

WJC

Well-known member
Bill & Omid,

First off, Bill, I think you misunderstood me. I was not suggesting that one try to set the diopter with both eyes open. In my experiment, which conclusively showed the irrelevance of object distance, I successively obscured one barrel with an objective cover. For most it would probably be quite adequate to follow the procedure: close right eye and set focus, close left eye and set diopter.

Perhaps you will allow me an unaccustomed digression, and I'm sure, Bill, that you will indulge me ;).
The German transport minister is strongly influenced by the automobile lobby and during the Diesel scandal eagerly jumped on the bandwagon of an emeritus professor for lung diseases. The professor was of the opinion that the EU limitations for NOx in (city) air of 40 µg/cu. m were far too stringent and that these levels should be relaxed. In some of his analogies he had miscalculated by several orders of magnitude and on a TV show he even asserted that the "air" that comes out of the exhaust of a modern Diesel is cleaner than what goes in! This showed a complete ignorance of how an internal combution engine works and that he had forgotten all his school chemistry to boot.

What I am trying to say here is that people are far too vulnerable to the opinions of "experts" who express themselves on topics which have no or only a peripheral relationship to their own speciality. Did the researchers quoted by Omid have sufficient data to calculate the virtual image distance of an observer and do they understand the workings af a Keplerian telescope?

Here is a simplified drawing from Wikipedia: https://en.wikipedia.org/wiki/Refracting_telescope#/media/File:Kepschem.png. Note that the rays emanating from the eyepiece are PARALLEL and that the virtual image is at INFINITY. A minor error is that the second distance labelled f2 on the right is eye relief and not the eyepiece focal length.

John

Hi, John and Omid,

Please note the last paragraph from a page in my first Bino book.

Cheers,

Bill
 

Attachments

  • Screen Shot 2020-11-04 at 2.33.29 PM.jpg
    Screen Shot 2020-11-04 at 2.33.29 PM.jpg
    115.8 KB · Views: 51

Tringa45

Well-known member
Europe
Hi, John and Omid,

Please note the last paragraph from a page in my first Bino book.

Cheers,

Bill

Yes, Bill, I bought it, read it and there's no disagreement there.

Regards,
John

PS: Keep an eye on Omid's thread. There's a storm brewing ;).
 
Last edited:

elkcub

Silicon Valley, California
United States
201101

Sorry to have so many of these bunching up. But I am going to try to get this one taken on by a higher-order publication and I would appreciate it if those who like to pick at me would be so good as to save me from myself. Since the stroke, the fingers are reluctant to work on command. :cat:

Bill

Bill,

I've read your paper several times, but find it puzzling. The emphasis is clearly on the value of 'staring' as discussed on pg. 2., but the procedural matter of how to set the diopter is not mentioned at all other than to disparage the known procedures as "trying to trick the brain."

...Learning to stare can preclude the eye’s involuntary input and limits focusing to that achieved
through the binocular’s focus mechanism
, leaving the observer in control of the whole focusing
operation, as opposed to having the two aspects of focusing fight each other while you try to attain a
precise and comfortable focus for an object at a given distance.
Not understanding the critical importance of learning to stare, observers have devised a few routines
to circumvent the real problem.

Two of the most common involve trying to trick the brain. * Both can be beneficial to the operation
and, although tantamount to placing a Band-Aid ®on a bullet hole, both have been endorsed in a
number of articles.
The first has the observer place a hand over one objective lens while focusing the other telescope.
Then, the procedure is reversed for the other side. For some, even that is not good enough. In the
second method, the observer must place the cap on one objective and reverse the process when a good
focus appears to have been achieved. Some observers promote one or both of these methods and some
satisfaction may be realized. Yet, how many times might a moving target disappear from sight while
using the first method or fishing around in your pocket for a lens cap to perform the second?
The person who has learned to stare need not bother with either of these stop-gap measures.

Sorry, I just don't get it.

Ed
 
Last edited:

WJC

Well-known member
Bill,

I've read your paper several times, but find it puzzling. The emphasis is clearly on the value of 'staring' as discussed on pg. 2., but the procedural matter of how to set the diopter is not mentioned at all other than to disparage the known procedures as "trying to trick the brain."

Sorry, I just don't get it.

Ed

Hi, Ed,

You are one of the few who can say, “I don’t get it,” that can cause me to go back to the drawing board.

1. There are two aspects to focusing a binocular.
2. One is mechanical; one is physiological.
3. By learning to stare, you can virtually remove the latter from the equation.
4. For some it is not easy, but it CAN be done.
5. This leaves the observer largely in control of the whole focusing operation—barring digging deeper into the matter and stirring up minutia.
6. For me, tricking the brain originates with any operation that tries to circumvent learning to stare.
7. “It is the mark of an educated mind to be able to entertain a thought without accepting it.”
— Aristotle :cat:

This morning on Brand X a fellow proffered:

"There is no need for such a complex set up to do collimation between both tubes (edit: APM 100 and 120 with eccentric collimation rings) only for collimation of all optical elements in each tube." While that only marginally relates to focussing, it is one of many dozen facts relating to binoculars ... that isn't a fact, at all.

That was spoken with seeming authority, but shows how much information the speaker lacks or doesn't understand.

Cheers,

Bill
 
Last edited:

Tringa45

Well-known member
Europe
es to

There is no need for such a complex set up to do collimation between both tubes (edit: APM 100 and 120 with eccentric collimation rings) only for collimation of all optical elements in each tube."[/I]
While that only marginally relates to focussing, it is one of many dozen facts relating to binoculars ... that isn't a fact, at all.

That was spoken with seeming authority, but shows how much information the speaker lacks or doesn't understand.

Cheers,

Bill

Bill,

I take it that you are aware that these binoculars have both optical tubes in a single housing without hinge? IPD is adjusted via the prism assemblies.

John
 

WJC

Well-known member
Bill,

I take it that you are aware that these binoculars have both optical tubes in a single housing without hinge? IPD is adjusted via the prism assemblies.

John

Yes, John,

Still, there are places where errors can creep in. Not nearly as bad as in binos with a hinge. But always a possibility. And if the prisms are properly aligned at one IPD setting, are they at all?

Cheers,

Bill
 

elkcub

Silicon Valley, California
United States
Hi, Ed,

You are one of the few who can say, “I don’t get it,” that can cause me to go back to the drawing board.

1. There are two aspects to focusing a binocular.
2. One is mechanical; one is physiological.
3. By learning to stare, you can virtually remove the latter from the equation.
4. For some it is not easy, but it CAN be done.

5. This leaves the observer largely in control of the whole focusing operation—barring digging deeper into the matter and stirring up minutia.
6. For me, tricking the brain originates with any operation that tries to circumvent learning to stare.
7. “It is the mark of an educated mind to be able to entertain a thought without accepting it.”
— Aristotle :cat:

...

Hi Bill,

For reference I've attached a section from "Basic Optics and Optical Instruments," pg. 5-12, which is a 1997 revision of the 1966 US Navy training manual for opticalman rating. I'm reasonably certain you're familiar with it and probably have a copy yourself.

With regard to instrument focusing, the first instruction is to "Allow your eye to become completely relaxed by viewing a distant area." There is no further specification as to how to relax, so I take it that your emphasis on staring fills in that detail. Correct?

Unfortunately, problems with that are: (a) it's unclear what 'staring' is behaviorally or the criteria needed assess that learning has taken place, and (b) there is no literature that I can identify related to staring and visual performance.

I assume that Navy instructions 2-4 are not in dispute, although they say nothing about a diopter adjustment, per se. I suspect this is simply a carry-over from the first edition when IF binoculars were in use. So, it's not too much of a leap to assume that after central focusing one side the diopter side should be set using the same procedure by moving it to the extreme PLUS position first, and so forth. What I find intriguing is the assertion that it's beneficial to focus from + to -. I vaguely recall human engineering literature on that subject but have been unable to find it.

So, summing up, my editorial suggestions are to provide a scientific basis for staring,* and incorporate step-by-step instructions for users to set up the diopter.

Ed

* For example a study showing that staring relaxes the rectus muscles.
 

Attachments

  • Navy method for focusing 00002.jpg
    Navy method for focusing 00002.jpg
    199.9 KB · Views: 34
Last edited:

WJC

Well-known member
Hi Bill,

For reference I've attached a section from "Basic Optics and Optical Instruments," pg. 5-12, which is a 1997 revision of the 1966 US Navy training manual for opticalman rating. I'm reasonably certain you're familiar with it and probably have a copy yourself.

With regard to instrument focusing, the first instruction is to "Allow your eye to become completely relaxed by viewing a distant area." There is no further specification as to how to relax, so I take it that your emphasis on staring fills in that detail. Correct?

Unfortunately, problems with that are: (a) it's unclear what 'staring' is behaviorally or the criteria needed assess that learning has taken place, and (b) there is no literature that I can identify related to staring and visual performance.

I assume that Navy instructions 2-4 are not in dispute, although they say nothing about a diopter adjustment, per se. I suspect this is simply a carry-over from the first edition when IF binoculars were in use. So, it's not too much of a leap to assume that after central focusing one side the diopter side should be set using the same procedure by moving it to the extreme PLUS position first, and so forth. What I find intriguing is the assertion that it's beneficial to focus from + to -. I vaguely recall human engineering literature on that subject but have been unable to find it.

So, summing up, my editorial suggestions are to provide a scientific basis for staring,* and incorporate step-by-step instructions for users to set up the diopter.

Ed

* For example a study showing that staring relaxes the rectus muscles.


Hi, Ed,

— For reference I've attached a section from "Basic Optics and Optical Instruments," pg. 5-12, which is a 1997 revision of the 1966 US Navy training manual for opticalman rating. I'm reasonably certain you're familiar with it and probably have a copy yourself.

Basic Optics and Optical Instruments is the Dover Press (civilian) version of The Navy’s Opticalman 3 & 2
NAVEDTRA 10205-C, my copy of which is on a bookshelf less than 6 feet from where I’m sitting.

— With regard to instrument focusing, the first instruction is to "Allow your eye to become completely relaxed by viewing a distant area."

One of two reason why I said, “a mile or more away.” We (Opticalmen) were taught that for OUR purposes “infinity” would be 2,000 yards or 6,000 feet—essentially 1 mile (which is actually 6,076.12 feet).

— There is no further specification as to how to relax, so I take it that your emphasis on staring fills in that detail. Correct?

Absolutely, but I feel confident that your training would illustrate that this is the point at which all instructions tend to get shaky as the physiological differences and accommodations of different observers come into play as indicated by your next comment:

— Unfortunately, problems with that are: (a) it's unclear what 'staring' is behaviorally or the criteria needed assess that learning has taken place, and (b) there is no literature that I can identify related to staring and visual performance.

— I assume that Navy instructions 2-4 are not in dispute, although they say nothing about a diopter adjustment, per se. I suspect this is simply a carry-over from the first edition when IF binoculars were in use. So, it's not too much of a leap to assume that after central focusing one side the diopter side should be set using the same procedure by moving it to the extreme PLUS position first, and so forth. What I find intriguing is the assertion that it's beneficial to focus from + to -. I vaguely recall human engineering literature on that subject but have been unable to find it.

You are certainly correct. But I had that error long ago and just keep doing it, like the person trying to proof his or her own work. In future writing, it will be corrected ... if I can remember. I just want to be helpful while trying to keep too many balls in the air.

— So, summing up, my editorial suggestions are to provide a scientific basis for staring,* and incorporate step-by-step instructions for users to set up the diopter.

Ed

* For example a study showing that staring relaxes the rectus muscles.

That is something to be looked into. But for me, that might be weeks away. I had the work of Dr. Adelson on tap, that’s why I could address it so readily. You seem to indicate there is a dearth of SCIENTIFIC information on staring. You are correct; more investigating and assimilation of what we know is in order.

But then, in the battle over 3-axis collimation and the many errors in thinking that keep pushing the inexperienced armchair optician to the forefront of the subject, I haven’t shrunk.

By the way, the “rectus muscles” relate more to collimation. The physiological aspect of focusing relate to the ciliary muscles.

Cheers,

Bill
 
Last edited:

elkcub

Silicon Valley, California
United States
Thanks Bill, the "ciliary muscles" are what I meant to say, ... as I'm sure you meant to say that one nautical mile is ~6076 feet. ;)

Ed
 

WJC

Well-known member
Thanks Bill, the "ciliary muscles" are what I meant to say, ... as I'm sure you meant to say that one nautical mile is ~6076 feet. ;)

Ed


Okay, Ed,

If you're going to be that way ... I meant 6076.12! 8-P :cat:

Cheers,

Bill
 

Omid

Well-known member
United States
Ed and Bill,

Thank you for mentioning the US Navy Opticalman training manuals. I searched online and noticed that poor quality PDF copies of these manuals are available on some archive sites. Upon further search I found a nice set of the original print versions for sale on eBay and decided to buy them (at a cost of more than $200). The books arrived yesterday and I have been enjoying reading them since :)

Sincerely,
-Omid
 

Users who are viewing this thread

Top