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- Magnification and move vision: (1 Viewer)

Pileatus

"Experientia Docet”
United States
John, my friend. It would have been enough to read more carefully, to avoid the headache ;)

try again:
the exit pupil is not the only factor to calculate the "light power" of binoculars, but it is essential to also use the magnification value. And in daytime hours (from sunrise to sunset), in the open field, the minimum power more than sufficient is on average equivalent to 7x17 = 8x18 = 10x20 = 25x32. Where to satisfy people with the lowest retinal sensitivity, simply increase the values to 7x21 = 8x22 = 10x25 = 25x40.

So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need. ... in daytime hours

Sorry, but I have the impression of talking to those who don't want to listen.

There is no worse deaf than those who do not want to hear!
Some homework for you...
https://imaging.nikon.com/lineup/sportoptics/how_to/guide/binoculars/basic/index.htm
 

WJC

Well-known member
200114

Rico70:

Rico, I think you are trying to offend the wrong people. Most folks have been exceptionally kind and patient with you. I speak with people from all over the world ... every week (Claudio Manetti from your country is a longtime friend) and I am beginning to believe that the problem lies not in your language barrier but with your understanding and experience barrier.

My interest in optics started at age 8 and I have spent my entire adult life in professional optical engineering and technologies, I published Amateur Telescope Making Journal (ISSN 1074:2697) for 10 years, made Chief Opticalman in the US Navy in record time, have published 4 books and several monographs on Optics, Telescopes, and Binoculars, coined the term “conditional alignment,” and taught optical engineering PhDs the difference between binocular collimation and conditional alignment.** In almost 50 years, I have never heard of “move vision, “light power,” or come in contact with a number of facts that seem to be known only to yourself.

I think my neighbors on BirdForum have been exceptionally kind. I would like to be. But you seem to shed facts and logic from knowledgeable people like water on a duck’s back. We all have to start somewhere. God gave us two ears and only one mouth; there was great wisdom in that. It seems, however, some of your assertions are from another dimension and I suggest before you start pontificating about optics that you spend a little time learning about optics. I would like very much to be your friend and have a long association with you on BF, but as long as you repeatedly ignore wise counsel or set that counsel at naught, it can’t be so. I realize that most newbies think binocular forums are totally about opinions. That is almost true but to overlook the helpful knowledge presented to you, thinking your pronouncements are facts that everyone—even those far more experienced than yourself—should embrace is a grave mistake.

** When I am forced to flash credentials, my more erudite friends take me to task. But you keep barreling forward, and I saw no other way to hopefully get your attention. It is my hope that you will join us—not as a superior, but—as a peer. :cat:

“Any fool can know; the point is to understand.” — Albert Einstein

Bill
 

St. Elmo

Well-known member
Show me one physiscs textbook to prove your point (I have a few, since I did my PhD work about the effect of light on living matter).

Maybe it was.....

51Vv0vqFDNL._SX394_BO1,204,203,200_.jpg

psst.... I just couldn't help that... it was right out there in front of me, so I went with it.... no offense meant, just a post to lighten the hearts of all you physicists, opticians, optical scientists, innocent bystanders, birders, do-gooders, friends, and cranky old men...
 

Pileatus

"Experientia Docet”
United States
Maybe it was.....

View attachment 715039

psst.... I just couldn't help that... it was right out there in front of me, so I went with it.... no offense meant, just a post to lighten the hearts of all you physicists, opticians, optical scientists, innocent bystanders, birders, do-gooders, friends, and cranky old men...
Steve Holzner, the author, was an MIT grad, earned a PhD. from Cornell and was on the faculty at both institutions.

https://www.legacy.com/obituaries/name/steven-holzner-obituary?pid=166827876
 
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Troubador

Moderator
Staff member
Supporter
That's right, Lee. What amazes you? Who has a 4-6mm pupil on a bright day?


In these twilight situations, we will need twilight binoculars. It also seems a little "foolish" to make this comparison-example. Are you joking?

Rico
Alexis has explained why exit pupils larger than the observer's own pupils is an aid to the comfortable use of binoculars.

As for twilight binoculars: these are very useful when you leave home in the twilight to watch twilight wildlife. It is not practical when leaving home on a bright and sunny morning to also carry pair of 56mm objective binoculars in case the day should darken or in case you stay out longer in the evening than planned.

But this means that what you seem to describe as the 'excessive exit pupil' of say an 8x42mm binocular becomes very useful if the day becomes darker.

Lee
 

John A Roberts

Well-known member
Australia
. . .
So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need. ... in daytime hours
. . .

As implied by the above, Rico's equation for the comparison of binoculars is: A) magnification x B) objective diameter squared
[ the above comparisons use a value of 200, where the value is the result of B) ÷ A) ]

So in order from greatest magnification/ smallest exit pupil:
- 25x70 (EP 2.8 mm dia; 6.2 sq. mm area)
- 10x44 (EP 4.4 mm dia; 15.2 sq. mm area)
- 8x40 (EP 5 mm dia; 19.6 sq. mm area)
- 7x37 (EP 5.3 mm dia; 22.1 sq. mm area)


Rico,

A) The problem remains: while the relationships are numerically equal, they are not equal in practice

As with many such equations seeking to provide a universal solution, the problem is not too obvious when looking at closely related examples e.g. 7x37 verses 8x40
However, the greater the disparity between the magnification/ EP of two binoculars, the more the comparison breaks down

Which is no surprise when considering the two extremes in the example:
- 25x70 (EP 2.8 mm dia; 6.2 sq. mm area) verses
- 7x37 (EP 5.3 mm dia; 22.1 sq. mm area) - with nearly 3.6 times the EP area

So the real issue is what does the equation mean, if anything? (see B) below)
And it also begs the question: If the equation is useful, why is it not already widely in use? It's not as if others would have not explored multiplying the two values
(and obvious comparisons can be made to the numerically neat, but limited practical utility of other simple equations, such as those for Relative Brightness and Twilight Factor)

As is the case with many of your past assertions, you’ve again seized on a narrow technical point while ignoring any other factors (especially practical limitations),
and have excluded any larger context


B) Radical Assertion

You can make the radical assertion that magnification can substitute for brightness, but that does not make it true
And you can come up with the term ‘light power’ and a simple supporting equation, but again that does not make it so

At best, your equation may be demonstrating a relationship that while technically true - within a very narrow range of values - is for all practical purposes irrelevant
Significantly, the equation does not help anyone to make a better choice in their selection of binoculars - and as such it only has potential to confuse the issue

But it’s much more likely that your assertion about brightness is simply an example of the fallacy of reification
i.e. assuming that because something can be described or named that it is real (see the screen grab from Wikipedia)


C) The onus remains on you to clearly explain your assertion

You’re the one making a claim that no one is familiar with, and that is also contrary to everyone else’s knowledge and experience

And if people cannot understand what you’re stating, it’s not the failure of the readers but of the author - you’re the one attempting to communicate a novel idea
e.g. your original post is a classic example of how not to explain a technical matter, particularly to a diverse readership


John
 

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Omid

Well-known member
United States
your original post is a classic example of how not to explain a technical matter, particularly to a diverse readership

John

What technical matter?! The original post is a work of art as I noted in post #11. Using more than 2500 words, it spirals beautifully yet says nothing of substance:

"She speaks, yet she says nothing"
-Shakespeare

This thread highlights an interesting aspect of human life: We love endless discussions about the least important matters. The amount of participation in any debate (and the media coverage of it) is inversely proportional to its significance. The decision to enter the war in Iraq occupied the British Parliament for only 18 hours. When it came to fox hunting, however, the British Parliament spent 225 hours debating the issue with rant upon rant against the evils of a sport that not a single one of its critics had ever witnessed. The same is true in this forum, in nearly all business meetings conducted in large corporation, in the media, in any "democratic" government and in nearly all family discussions. Unfortunately, I am too busy to participate in this fun sport it so I let you guys continue..

Cheers!:t:

PS. The 17th century Persian poet Saib Tabrizi has a line that roughly translate to this: Stop complaining that there is no new concept left for poetry, a true poet can spend all his life describing his beloved's hair! ;)
 
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WJC

Well-known member
What technical matter?! The original post is a work of art as I noted in post #11. Using more than 2500 words, it says precisely nothing!! ;);)

"She speaks, yet she says nothing"
-Shakespeare

This thread highlights an interesting aspect of human behavior: We love endless discussions about the least important matters. The amount of participation in any debate (and the media coverage of it) is inversely proportional to its significance. The decision to enter the war in Iraq occupied the British Parliament for only 18 hours. When it came to fox hunting, however, the British Parliament spent 225 hours debating the issue, with rant upon rant against the evils of a sport that not a single one of its critics had ever witnessed. :t::t:

The same is true in this forum, in nearly all business meetings conducted in large corporation, in the media, in any "democratic" government and in nearly all family discussions. Unfortunately, I am too busy to participate in this fun sport it so I let you guys continue..

Cheers! ;)

Don't blame the clown for being a clown; blame yourself for going to the circus ... guilty! :cat:

BC
 

Troubador

Moderator
Staff member
Supporter
It doesn't help when the translation of Rico's statement emerges as an assertion that certain binocular formats are 'too bright' when I think he means unnecessarily bright. So I now think he doesn't mean dazzling but rather more brightness than can be made use of.

Alexis has countered this effectively in Post 118 but I would add that larger EPS also facilitate the aquisition of an image by spectacle users whose binoculars are not guided to one's pupils by the insertion of the eyecups into one's eye sockets. Alignment of binos with one's pupils is a skill that takes time to learn as eyecups can slip across one's spectacle lenses especially in situations where one is peering around a boulder or a bush at nearby bird or animal and one's position is anything but usefully upright and aligned.
And then there is the occurance of varying light levels during the day which can mean 'unnecessarily large' EPs in one part fo the day can be the minimum required during another part.

Lee
 

Omid

Well-known member
United States
Don't blame the clown for being a clown; blame yourself for going to the circus ... guilty! :cat:

BC

Well said. I admit that I am guilty for joining the circus! Out I go, no more posts in this thread ;)
 

leonardo_simon

Well-known member
I don’t think Rico is intentionally trying to offend anyone

I don’t see any instances in any of his posts of any personal comments although I admit I have not read them all in detail.

Anyway He doesn’t deserve the abuse some people are giving him here.

If you are offended it may be kinder to ignore this thread.
 
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WJC

Well-known member
I don’t think Rico is intentionally trying to offend anyone

I don’t see any instances in any of his posts of any personal comments although I admit I have not read them all in detail.

Anyway He doesn’t deserve the abuse some people are giving him here.

If you are offended it may be kinder to ignore this thread.

Oh, that you would be correct.:cat:

BC
 

typo

Well-known member
It doesn't help when the translation of Rico's statement emerges as an assertion that certain binocular formats are 'too bright' when I think he means unnecessarily bright. So I now think he doesn't mean dazzling but rather more brightness than can be made use of.....Lee

Lee,

I think it's worth looking again at Rico's post again in it's entirety so we don't take this "too bright" comment out of context.

points 1 and 2: the exit pupil is not the only factor to calculate the "light power" of binoculars, but it is essential to also use the magnification value. And in daytime hours (from sunrise to sunset), in the open field, the minimum power more than sufficient is on average equivalent to 7x17 = 8x18 = 10x20 = 25x32. Where to satisfy people with the lowest retinal sensitivity, simply increase the values to 7x21 = 8x22 = 10x25 = 25x40.

So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need.

"the exit pupil is not the only factor to calculate the "light power" of binoculars, but it is essential to also use the magnification value."

It is really important to understand clearly the following fact. It is absolutely impossible for a binocular to produce more 'light power' or brightness if you prefer, than can be seen by the naked eye. This is not up for debate. It's a fundamental science principle that passive optics cannot increase the level of energy. Binoculars can reduce it of course, through transmission loss and exit pupil limitations. Any formula that predicts an increase is automatically invalid. As we shall see, magnification is irrelevant.

"And in daytime hours (from sunrise to sunset), in the open field, the minimum power more than sufficient is on average equivalent to 7x17 = 8x18 = 10x20 = 25x32. Where to satisfy people with the lowest retinal sensitivity, simply increase the values to 7x21 = 8x22 = 10x25 = 25x40."

You might not be aware of quite how much light levels vary while using a binocular between dawn and dusk, but you have acknowledged that pupil diameter can vary significantly in that time. If Rico's is right then 7x17, 8x18, 10x20 and 25x32 will all produce a value of around 63 and will be equally bright by his theory. Those would have exit pupils of 2.4mm, 2.25mm, 2.0mm and 1.28mm respectively. Even 2.4mm can be severely limiting at times, and though we might might not all have Rico's quite miraculous sensitivity to light level, I suspect most would notice a 72% reduction in light level across that range. Roco's formula implies that the light must be amplified, but that is impossible as I stated.

I really don't have much idea what Rico means by "people with the lowest retinal sensitivity", but those with macular degeneration will certainly need a bit more help than that!

"So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need."

Rico's formula gives values 196, 196, 200 and 194 respectively or rougly 3 times brighter than "sufficient" according to his claims, but note that a 25x70 has 2.8mm EP with a 72% reduction in area compared to the 7x37. On that overcast day when I tried the Celesteon 25x50 I don't imagine many here would have failed to notice how dingy it was.

It can certainly pretty hard at times to fathom out what on earth Rico is talking about, but Lee, do you really think all that can be explained away by translation issues? Was all that fuss about binocular stability all a misunderstanding too? There really are much more fundamental issues to consider.
 

leonardo_simon

Well-known member
I am a neuroscientist who enjoys watching birds. I would like to add another angle of discussion to this thread.

I've been following this thread with interest -- in parts there does seem to be a conflation of the optical qualities of binoculars with what is seen by the user.

Although much of the thread discusses the former (how binoculars work) I would argue that a more thorough consideration of the human visual system is also required.

Early theories of perception (e.g. vision, pain) (e.g. Descartes in the 1600's), considered it to be a "bottom-up" process. For example light is focused by the eye's lens on the retina, it gets transmitted to the brain, which like a camera transduces the signal and you 'see' the image.

However, we now realise it's not as simple as that -- as this theory couldn't explain how optical illusions work, and for the brain to work this way would be super-resource intensive. Modern thinking (derived from Helmholz in the late 1800's but having gained traction much more recently i.e. the past 30yrs) now views perception as a much more 'top down' process.

The brain is thought to have an 'internal model of the world' that it then checks using 'sparse sampling' against the inputs it receives. This internal model is referred to as a set of 'priors', although I'll use the term 'expectation' here as that's a more familiar word for most people. Thus expectation has a powerful effect upon what you see (or feel). Expectation may be influenced by your beliefs that may be innate or learned. Expectation may be influenced by your personality or your mood.

Hence optical illusions, hence mis-seeing things at dusk (e.g. you think you see your friend approaching you, it looks like your friend, until you get really close and then it doesn't). Interestingly there are even a few words about the influence of expectation in birdwatching in the introduction to Sibley's Bird Guide.

A more detailed description of this theory of perception can be found on this wikipedia page: https://en.wikipedia.org/wiki/Predictive_coding

So going back to the discussions in this thread --

A comprehensive model of what we see through binoculars would need to incorporate both the instrument and visual system of the user.

We need to remember that everyone sees things differently.

Not only are our eyes different but importantly everyone's brains are wired differently and expectation has a powerful influence.


------------------------------



footnote

Quotes from Sibley Birds East, 2016 Edition, page xi (section heading Psychological Effects and Mistakes)

"Expectation has a very powerful psychological effect, and can even alter the way we perceive colors and shapes"

"These effects are operating all the time and we are usually unaware of any bias"
 
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Troubador

Moderator
Staff member
Supporter
Interoception Post 134

Very interesting post. Regarding expectation, I read about the case of a man who 'saw' church stained-glass windows high in this visual field of view. He wasn't seeing religious visions though. He had some kind of neural damage which created a black hole in his vision and it seems his brain, 'knowing' this to be 'impossible' filled this gap with an image from his memory and it was high in his visual field because this is where the window was in real life.

Also, when I am looking for otters among the islets, rocks and skerries in the sea off the West of Scotland and I scan the big fringes of brown seaweeds too quickly, all I see is brown seaweed. There appears to me be plenty of detail but this is an illusion. I need to slow down the speed of my eyes traversing the scene and when I reach a certain speed I truly see what is there and if I am lucky I might see an otter. It seems to me that when I scan rapidly my brain reproduces an image of an unbroken bank of seaweed, slow down and I see the tips of rocks sticking up and other details. I wonder if this is an example of expectation.

Lee
 

typo

Well-known member
Introception,

Thank you for that eloquent explaination.

Perhaps you will find it useful to have a look at the discussion that followed Rico's original post on this subject. https://www.birdforum.net/showthread.php?t=384516

Some of us did try to explain to Rico that 'brightness' is a human perception both in the thread and by personal message, but it wasn't well received! We pointed out theclassic studies on binocular performance by Berek, Blackwell, and particularly the best known by Köhler and Leinhos from Zeiss all started with some puantitative measures of perception. The latter study resulted in a mathematical fit to the response data, the much used, abused and widely misunderstood Twilight factor. Evidently Rico didn't feel such niceties were necessary to test his theory and consequently has raised this particular backlash as countless individuals sense-check his assertions.

His other main obsession, and the original subject of this thread, is that not only do high power binoculars like his Celestron 25x70 deliver more luminous energy, that the resulting shake from the weight and imbalance magnified 25 times is no impairment to resolvable detail, and even women and children obviously enjoy the benefits. Perhaps unsurprisingly that's been a difficut sell as well. https://www.birdforum.net/showthread.php?t=385328

The subject of expection influencing evaluations has cropped up many, many times on the forum, but I really do appreciate you putting the correct name to it. I find the psycho literature almost impenetrable. I've lost count of how many times I've been told by binocular salesmen the punters only see what they want to see. Many point to Swarovski's success in marketing the EL SV. The whole birding world believed they could see the 2% increase in peak transmission. Of course it's that would be impossible. (I suspect the real story has more to do with 2006 revision of the CIE photopic response curve.) Of course you will find plenty of evidence here for price and brand influencing expectation.

Cheers,

David
 
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CharleyBird

Well-known member
My 2c:
The thing about highish magnification binoculars is that when you want to use them, when you most need to use them to scan a vista, it's usually an unsuitable area i.e. a windy sea shore, a windy estuary, a windy mountainside. You need a fixed support, at the very least a fencepost etc. to lean on.

For this reason I have not bought any 15x56 optics, ostensibly sold as hand-holdable. While I have tried (and liked them) for a short time in a shop, they would be so very annoying to use outdoors other than on a tripod.
This I expected and found with my (large, light and hand holdable indoors) APM MS ED 16x70, which are great to use...on a tripod.

Like the majority here, 7-10x magnifications are what I've settled on to carry.
 

WJC

Well-known member
Physiology

I am a neuroscientist who enjoys watching birds. I would like to add another angle of discussion to this thread.

I've been following this thread with interest -- in parts there does seem to be a conflation of the optical qualities of binoculars with what is seen by the user.

Although much of the thread discusses the former (how binoculars work) I would argue that a more thorough consideration of the human visual system is also required.

Early theories of perception (e.g. vision, pain) (e.g. Descartes in the 1600's), considered it to be a "bottom-up" process. For example light is focused by the eye's lens on the retina, it gets transmitted to the brain, which like a camera transduces the signal and you 'see' the image.

However, we now realise it's not as simple as that -- as this theory couldn't explain how optical illusions work, and for the brain to work this way would be super-resource intensive. Modern thinking (derived from Helmholz in the late 1800's but having gained traction much more recently i.e. the past 30yrs) now views perception as a much more 'top down' process.

The brain is thought to have an 'internal model of the world' that it then checks using 'sparse sampling' against the inputs it receives. This internal model is referred to as a set of 'priors', although I'll use the term 'expectation' here as that's a more familiar word for most people. Thus expectation has a powerful effect upon what you see (or feel). Expectation may be influenced by your beliefs that may be innate or learned. Expectation may be influenced by your personality or your mood.

Hence optical illusions, hence mis-seeing things at dusk (e.g. you think you see your friend approaching you, it looks like your friend, until you get really close and then it doesn't). Interestingly there are even a few words about the influence of expectation in birdwatching in the introduction to Sibley's Bird Guide.

A more detailed description of this theory of perception can be found on this wikipedia page: https://en.wikipedia.org/wiki/Predictive_coding

So going back to the discussions in this thread --

A comprehensive model of what we see through binoculars would need to incorporate both the instrument and visual system of the user.

We need to remember that everyone sees things differently.

Not only are our eyes different but importantly everyone's brains are wired differently and expectation has a powerful influence.


------------------------------



footnote

Quotes from Sibley Birds East, 2016 Edition, page xi (section heading Psychological Effects and Mistakes)

"Expectation has a very powerful psychological effect, and can even alter the way we perceive colors and shapes"

"These effects are operating all the time and we are usually unaware of any bias"

200116

Hi, interoception,

I rarely enter the realm of neurosciences. I believe the last time was when I stubbed my little toe on a large, heavy stool that found its way to the middle of my hallway in the middle of the night.

However, since you are relatively new to the bino portion of BirdForum, please let me assure you that this has been covered many times by Ed Huff (NASA Senior Scientist), Professor Gijs van Ginkel, Professor Peter Wolliams (i.e. really smart dude), myself (optical screw turner), and others. I have beat this dead horse ... to death ... and continue to do so.

The attached is from the front matter of my first complete binocular book (that BirdForm won’t allowed to mention by name). I think the one-liner in bold and the paragraph directly above addresses the matter nicely. :cat:

Cheers,

Bill

PS You might be interested in my treatise on the importance of spatial and dioptric accommodations.
 

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Kammerdiner

Well-known member
I'm not too sure if this thread is about birding or not, but it's pretty obvious high mags should be left to scopes.

I was recently on the west coast, out for a walk with a nephew, and he said what's that? Quarter mile away I said Common Merganser. I had 8x with me just to confirm. Not really needed actually.

I've recently been debating whether a 10x would be worth the investment My dedicated bino is an 8.5x SV, and I'm not sure anything more (short of a scope) would be worth my time. Any thoughts?

PS: I still travel with my little Nikon ED50 at 27x. Not my favorite but it gets me through the airports. I don't know why but the TSA cannot figure out what a carbon fiber travel tripod is. They got into my bag both ways. I'm going to start saving the notices and lining them up on top of my undies, lol. Oh well, they mean well.
 

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