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- Magnification and move vision:

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Old Wednesday 15th January 2020, 08:09   #126
John A Roberts
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Originally Posted by Rico70 View Post
. . .
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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Old Wednesday 15th January 2020, 18:13   #127
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Originally Posted by John A Roberts View Post

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!

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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Old Wednesday 15th January 2020, 19:36   #128
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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.

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!

BC
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Old Wednesday 15th January 2020, 19:52   #129
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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.

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Old Wednesday 15th January 2020, 20:39   #130
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Don't blame the clown for being a clown; blame yourself for going to the circus ... guilty!

BC
Well said. I admit that I am guilty for joining the circus! Out I go, no more posts in this thread
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Old Wednesday 15th January 2020, 21:03   #131
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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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Old Wednesday 15th January 2020, 21:14   #132
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Originally Posted by interoception View Post
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.

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Old Thursday 16th January 2020, 03:53   #133
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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.

Quote:
Originally Posted by Rico70 View Post
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.
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Old Thursday 16th January 2020, 06:24   #134
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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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Old Thursday 16th January 2020, 07:46   #135
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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.

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Old Thursday 16th January 2020, 07:55   #136
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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 Khler 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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Old Thursday 16th January 2020, 09:38   #137
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Thanks all.
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Old Thursday 16th January 2020, 14:41   #138
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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.
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Old Thursday 16th January 2020, 18:02   #139
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Physiology

Quote:
Originally Posted by interoception View Post
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 wont allowed to mention by name). I think the one-liner in bold and the paragraph directly above addresses the matter nicely.

Cheers,

Bill

PS You might be interested in my treatise on the importance of spatial and dioptric accommodations.
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Old Thursday 16th January 2020, 20:35   #140
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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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Old Thursday 16th January 2020, 20:45   #141
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Despite being a biologist, and one who is interested in optics and the evolution of animal color patterns that are under natural and sexual selection (and thus the perceptual abilities of predators and potential mates), I have to admit that I've not had much use, in evaluating or selecting binoculars, for discussion of individual variation in perceptual differences that result from differences in neural processing. I want optics that work for _me_. Nevertheless, in addition to testing them myself, I find both objective measures and subjective reports from reliable observers (whose biases are consistent from review to review, and who make claims about the strengths and weaknesses of bins in terms of relative differences in performance such as through side-by-side comparison) very useful in sorting through binoculars. Our retinal ganglia and our brains may work differently from one another, and we may all have different prior expectations, but _every_ observer benefits from a richness of good clean data for evaluation through those expectations and with which to shape those expectations over time. I want a binocular, as much as possible, to deliver the light to my eye such that the view is magnified and nothing else. Consequently, I find descriptions of light transmission, field curvature, astigmatism, chromatic aberration, FOV, eye-relief and the like to be quite useful and quite adequate for determining whether I will like a bin. Moreover, if my perception would benefit from, e.g., emphasizing particular wavelengths in a particular situation, I'd prefer to add a filter, not use a bin that was itself otherwise always biased.

The above is just a cranky thought and an attempt to share why some of us (or at least I) largely ignore protestations that we can't really discuss the merits of bins among observers unless we take into consideration differences in individual perception stemming from differences in neural processing.

--AP

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Old Thursday 16th January 2020, 20:54   #142
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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.
Your post takes me back to my original reply to the OP. See the latter parts of that post #2 (in this thread) as well as my post #47 (in this thread) for my thoughts on the merits of 8x versus 10x versus 30x scope for birding.

--AP
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Old Thursday 16th January 2020, 21:14   #143
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Your post takes me back to my original reply to the OP. See the latter parts of that post #2 (in this thread) as well as my post #47 (in this thread) for my thoughts on the merits of 8x versus 10x versus 30x scope for birding.

--AP
Thanks, Alexis. Your serious experience is always appreciated. Despite the itch to buy another bino, I can't think of a good reason to do so. 8-8.5x is plenty. After that it's time for a scope.

PS: another shameless plug for the Meopta 30-60x S2. I never tire of it, after something like 7 years??

Mark
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Old Friday 17th January 2020, 09:38   #144
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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, that's exactly how it is! Simply so. "unnecessarily bright"

I hope it will be understood in this way from now on, avoiding other useless future discussions about it.
Or at least, that they are discussed by the interested parties in a facilitated way for everyone, in the place provided.
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Old Friday 17th January 2020, 09:54   #145
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Originally Posted by Gijs van Ginkel View Post
Rico70, post 114,
You keep insisting that magnification is a factor in image brightness. It is not, only the combination of light transmission and size of exit puil determine image brightness. 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).
Emeritus Professor Gijs van Ginkel, I don't think you will find a direct quotation of this in the physics book, but I invite you to do some tests, before ruling against without having tried.
I am almost certain that you have the technical skills to do these tests "as it should be". So I trust that you will have the right scruple and above all an undisputed intellectual honesty in providing your results.
This however is not the right place to discuss "twilight power" and therefore I expect a detailed answer in the prepared topic:
https://www.birdforum.net/showthread.php?t=384516

If you have questions about the test method, I will be happy to answer in that most suitable place.
Thank you for your time.
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Old Friday 17th January 2020, 10:42   #146
Gijs van Ginkel
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Rico70, post 145,
You ask me to prove your statement, that is the wrong way to do it. It is upon you to prove your point and I will be very interested to see how you do it.
Best regards,
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Old Friday 17th January 2020, 10:56   #147
Rico70
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Binastro, I gather here only what concerns the topic, on which I feel I should intervene
Quote:
Originally Posted by Binastro View Post
Skymaster provide a tripod adapter for the 25x70. It is there to be used.
There is no need to use that cheap plastic bankruptcy support, which only introduces disproportionate vibrations. Better to throw it directly in the specific trash bin (recyclable plastic) and if anything use other much more suitable supports.
For example, it will be preferable to support the binocular to a tree or a pole or monopod, rather than making use of that inadequate support.

Quote:
Originally Posted by Binastro View Post
Hand holding a 25x70 will reveal glimpsed coarse detail that is invisible with even a good 10x42. But the fine detail is not seen.
Because it's as I was explaining to you, that the eye needs a passage greater than 2.5x to get to a higher level of detail.
And I'm glad you found it independently and without forcing.
If you compare a 34x to a 10x, you can see that now the level of detail has actually increased.

Last edited by Rico70 : Friday 17th January 2020 at 11:00.
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Old Friday 17th January 2020, 12:00   #148
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Rico70,
With regard to your statements of free hand observation with binoculars with high magnification it is worthwile to read a study by Ostapova and Potikhnova, publsihed in the Sov. J. Opt. Technology 58, sept 1991, pages 542-544.
The investigations were performed under field conditions and employed a large number of observers and specially developed tests. In the investigations were used commercial 4x20, 6x24, 10x50 and 15x60 binoculars both handheld or supported (rigid mounting).
It is worthwile to read the whole paper, but the investigators conclude: "when viewing distant objects in telescopic instruments (binoculars or telescopes) the efficiency of of the visual perception deceases drastically because of hand tremor. The resolution limit of the "observer-instrument" system is degraded by a factor of 1,1 to 1,4.
The probability of recognizing equal-size images of objects is reduced and the recognition time increaes approximately proportionally to the increase in magnification".
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Old Friday 17th January 2020, 12:23   #149
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In case anyone wasn't sure about Rico's claims that 'brightness' changing with magnification there are loads of articles on the internet that state plainly that it cannot, but this one popped out first this morning.
http://www.physicsinsights.org/simpl...ghtness_1.html

As for this claim in #147: "Because it's as I was explaining to you, that the eye needs a passage greater than 2.5x to get to a higher level of detail."

Which is pretty hard to understand to say the least.

David

Last edited by Troubador : Friday 17th January 2020 at 16:45.
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Old Friday 17th January 2020, 13:23   #150
Rico70
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Quote:
Originally Posted by Gijs van Ginkel View Post
"The probability of recognizing equal-size images of objects is reduced and the recognition time increaes approximately proportionally to the increase in magnification".
I undoubtedly agree with the "recognition time", as I have already mentioned several times. I have never done careful studies if the time increases in proportion to the magnification, but I'm in complete disagreement with the attempt to argue that greater magnification decreases the visibility of detail due to the shake. And that therefore a 7x will be more detailed than a 10x (for example).

This is not science! ... this is a huge nonsense ...

Exactly like what was written in the article that David validate, without even having noticed that following the calculations, the result does not agree with the curve represented (that is "waste paper"!).

Do not you agree, Gijs?

Last edited by Rico70 : Friday 17th January 2020 at 15:53.
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