- Magnification and move vision: (1 Viewer)

[Alexis Powell]

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

 

[Alexis Powell]

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

 

[Kammerdiner]

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

 

[Rico70]

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.

 

[Rico70]

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.

 

[Gijs van Ginkel]

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,
Gijs van Ginkel

 

[Rico70]

Binastro, I gather here only what concerns the topic, on which I feel I should intervene

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.

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.

 

[Gijs van Ginkel]

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".
Gijs van Ginkel

 

[typo]

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/simple_optics_brightness_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

 

[Rico70]

"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?

 

[Pileatus]

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 claims, 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?

Any birder with enough real world experience will tell you you are wrong. In windy conditions, for example, a 10X can be useless where the 7X will reveal important identification details. The "failure" of the 10X is handshake due to wind. Any experienced spotting scope user will tell you they often reduce magnification due to wind vibration on the tripod.

Your persistence that higher magnification, regardless of handshake effect, is always superior cannot be supported by end-user field data. You seem to be arguing that greater details appear in higher magnifications whether the user perceives them or not. Such an idea is incorrect.

 

[Troubador]

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 claims, 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?

Rico
I suggest there is a magnification threshold, at around 10-12x up to which the perception of detail increases with magnification as you suggest.

Above this threshold, lets say from 15x and higher, using hand-held instruments, the perception of useful and usable detail decreases with magnification. The detail is made available by the binocular but the effect of bino tremble makes this detail unusable.

This is my pratical experience not a theory.

Lee

 

[Rico70]

I suggest there is a magnification threshold, at around 10-12x up to which the perception of detail increases with magnification as you suggest.

Above this threshold, lets say from 15x and higher, using hand-held instruments, the perception of useful and usable detail decreases with magnification. The detail is made available by the binocular but the effect of bino tremble makes this detail unusable.

In my opinion, this is impossible. I understand your very high level of moderation, which I admire and carry in my heart, and which makes itself clear in the best form. On this I can only take off my hat. :t:

But 15x limit (or other) could be inconsistent with the rest, since it is not possible to say that 2+2= 4 and after say also that 4+4= 7

I hope this metaphor is clear. The greater detail (e.g. 2x) is there and will be visible, or it is not there and therefore there is some unknown factor that somehow makes the 15x less detailed than the 30x (for example).

If the greatest detail is there and is present when the two binoculars are compared on tripod, why on earth 2+2= 4, but 4+4= 7 (for example)?




ps:
I recommend to let's leave aside personal experiences (which are conditioned by too many subjectivities both of the user and of the binoculars, and of the environment) to focus on the objective principles that regulate magnification and shake vision.

 

[Rico70]

In windy conditions, for example, a 10X can be useless where the 7X will reveal important identification details. The "failure" of the 10X is handshake due to wind.

And why should it? has the 10x changed the wind?

You seem to be arguing that greater details appear in higher magnifications whether the user perceives them or not.

You are distorting almost everything I say, to say what you want.
But I guess you didn't read correctly or didn't understand what I wrote.
If you have questions for clarification, I am more than helpful, but if you have unnecessary controversies, keep them to yourself and adjust with the moderator.

 

[Pileatus]

And why should it? has the 10x changed the wind?


You are distorting almost everything I say, to say what you want.
But I guess you didn't read correctly or didn't understand what I wrote.
If you have questions for clarification, I am more than helpful, but if you have unnecessary controversies, keep them to yourself and adjust with the moderator.

Yes, by all means, clarify.
Please discuss the effects of wind induced handshake on perception vis-a-vis binocular magnification. Limit response to handheld instruments.

 

[Troubador]

In my opinion, this is impossible. I understand your very high level of moderation, which I admire and carry in my heart, and which makes itself clear in the best form. On this I can only take off my hat. :t:

But 15x limit (or other) could be inconsistent with the rest, since it is not possible to say that 2+2= 4 and after say also that 4+4= 7

I hope this metaphor is clear. The greater detail (e.g. 2x) is there and will be visible, or it is not there and therefore there is some unknown factor that somehow makes the 15x less detailed than the 30x (for example).

If the greatest detail is there and is present when the two binoculars are compared on tripod, why on earth 2+2= 4, but 4+4= 7 (for example)?




ps:
I recommend to let's leave aside personal experiences (which are conditioned by too many subjectivities both of the user and of the binoculars, and of the environment) to focus on the objective principles that regulate magnification and shake vision.

Unfortunately Rico the practical fact is that the experiences of everyone on here is that at magnifications higher than 10x the extra detail captured by the binoculars is not accessible or usable due to effects of bino shake and even 10x can be unusable on a windy day.

These are real and consistent experiences and no amount of theory can deny these.

Lee

 

[Rico70]

discuss the effects of wind induced handshake on perception vis-a-vis binocular magnification

the wind effect is comparable to the hand effect, and in a controlled test (avoiding subjectivity), it will produce the same movement in any binocular with any magnification (excluding ergonomic factors, weight, etc.).

Now, if the shake is the same, how is it possible that for example the 7x is more detailed than the 10x?

The answer is that it is impossible and that in this case it is only an appearance, a mental perception, a cerebral illusion, as also @interiception had mentioned here
https://www.birdforum.net/showpost.php?p=3947940&postcount=134

The fact of not seeing the motion of the hand (or of the wind), or in any case of seeing less of this effect of the shake with 7x, does not mean that you are seeing more details, but on the contrary that you are seeing less of it.