Chromatic aberration (1 Viewer)

WJC · Jan 3, 2020

Troubador said:
Rico I would be cautious about assuming these people saw a steady and informative image, especially if they were not accustomed to using binos. I have met many people who did not know of the existence of the dioptre adjuster on their binos and just assumed that the unsharp image they saw was typical and as good as it could get. They were amazed when shown how to adjust the dioptre. I have given others binos to try with not only the dioptre adjusted to a stupid setting but also with one eyecup down and one eyecup up. Most people did not question this probably due to a combination of not being sure something was wrong and not wanting to appear ignorant by asking about it. Of course they learned something when shown how to set the eyecups and the dioptre.

I suspect that the people who tried out your higher magnifications just thought a shaky image was normal. Even if they thought 'this shaky image cannot be normal' they may not have commented in case they appeared ignorant or stupid.

Lee

And then we have the old fellow who told me the ship-mounted bino he used during WWII was a “1,000 power.” He didn’t know that he was talking to a Navy Opticalman who had been inside every model ever made and that they were all 20x120 (4.77-inch). Although it probably wouldn't have mattered because he obviously needed bragging rights. Anyway, the SIZE of a bino ALWAYS DETERMINES its magnification ... RIGHT?!

This is just ONE of the MANY reasons why “ultracrepidarian” is such a great word. :cat:

Bill

Rico70 · Jan 3, 2020

Troubador said:
I would be cautious about assuming these people saw a steady and informative image, especially if they were not accustomed to using binos.

Lee, it was enough for me to see their smiles and listen to their comments of satisfaction in seeing the animals so well, to make me understand that they had observed the beauty as they should.
I understand that many passersby may not know the dioptric adjustment, but if the binoculars are already well adjusted and in focus on the animal, it is sufficient to explain to him how to adjust the IPD and how to keep the instrument and they will see correctly inside the binoculars.

Speaking of AC (we're on topic), I've often read negative comments written by "expert people" (or so it seemed), regarding the typical low cost binoculars, in high magnification formats, such as 15x70, 20x80, 25x70 (like mine), etc.
Many of them complained of exaggerated AC during the daytime observations and therefore discarded the binoculars, although in the night observations of the starry sky, these binoculars worked well.

I state that there is nothing controversial in my words, but I was very impressed by these "bizarre reactions", as it would have been more than enough to diaphragm the objectives of 2 or 3 stops, to have fabulous daytime observations, with greater DOF and total sharpness of the images.

Sometimes, we consider ourselves "experts", but Socrates knew how incompetent he was!

Rico70 · Jan 3, 2020

eronald said:
I used to have "magic hands", but I now find holding something steady annoying.

Hi Edmund, I would like to specify that when I use the 25x70, I support it whenever I can to a pole or to a plant or to what I find stable, to immobilize at least one of the two objectives. The weight to be supported quickly becomes annoying (1.2Kg) and comfortably fixing the observed objects with more calm and less flickering is certainly preferable for me too (sometimes I use the monopod).

But I use it many times even "in flight", without supports (only the hands) and for several minutes. If it weighed 800g it would be better and easier to hold longer. And anyway, I find it very useful also for birds and moving objects more than 30m away. For example, it is easy to follow planes without annoying motion. Sometimes I recognize the models or flags they belong to.
But I had to do various tests first, on how to keep it in the best position and then get used to the "vision in movement", which is certainly not instinctive at 25x (but it is not even at 8x).

WJC said:
Anyway, the SIZE of a bino ALWAYS DETERMINES its magnification ... RIGHT?!

Right, Bill. Unfortunately, that's the way it is. Impossible to cheat Physics.
Blessed are those who are satisfied with 8x or 7x or 6x ... which will have the "easiest dimensions".

tenex · Jan 4, 2020

Rico70 said:
But I had to do various tests first, on how to keep it in the best position and then get used to the "vision in movement", which is certainly not instinctive at 25x (but it is not even at 8x).

This is exactly the point I've always made: any magnified view, even 7x, has added jitter handheld, and somehow the brain must learn to deal with it, at least up to a certain point which may vary with the individual as well as the ergos of the instrument, but often hasn't been fully explored. Even I am inclined to think 25x could be too much for handholding, but I've never given it a serious try, as you describe yourself. Perhaps when the 25x SLC comes out...

Troubador · Jan 4, 2020

tenex said:
This is exactly the point I've always made: any magnified view, even 7x, has added jitter handheld, and somehow the brain must learn to deal with it, at least up to a certain point which may vary with the individual as well as the ergos of the instrument, but often hasn't been fully explored.

This is absolutely my experience too and the jitter varies with the source giving the brain more than one puzzle to learn. By 'source' what I mean is that, certainly in my case, jitter caused by the thumping of my heart after a stiff climb to an observation point, is the least problematic because it has a regular rhythm whereas the other extreme is jitter caused by a gusting wind with irregular pulses and a complex of interferences mixing gusts that move my arms by a noticeable amount but combined with a varying amount of higher frequency vibration. Heavier binos can help 'dampen' this kind of jitter but can cause a different kind due to arm fatigue holding the binos up for long periods while observing behaviour.

Bino jitter or shake is not a simple subject.

Lee

Pileatus · Jan 4, 2020

WJC said:
And then we have the old fellow who told me the ship-mounted bino he used during WWII was a “1,000 power.” He didn’t know that he was talking to a Navy Opticalman who had been inside every model ever made and that they were all 20x120 (4.77-inch). Although it probably wouldn't have mattered because he obviously needed bragging rights. Anyway, the SIZE of a bino ALWAYS DETERMINES its magnification ... RIGHT?!

This is just ONE of the MANY reasons why “ultracrepidarian” is such a great word. :cat:

Bill

If the shoe fits...

PS
http://www.worldwidewords.org/weirdwords/ww-ult1.htm
crepidam

NDhunter · Jan 5, 2020

Jay_Feather said:
Before I begin this post I am sorry if this is in the wrong forum.

Hello,
If the magnification on binoculars is higher can it increase Chromatic aberration. I mean this with Nikon binoculars. Thankyou all :t:

Henry

Henry, you have made a very good question, and the answer is yes, a higher magnification binocular is harder to make without chromatic aberrations.

So that means comparing an 8X as standard, a 10x, 12x and 15x and larger
will often have more chromatic aberrations.

You mentioned Nikon here, but it does not matter which brand.

Another thing which is important is the objective size, most of the time a smaller objective size, such as 30mm or smaller, will have less chromatic aberration than a larger sized objective such as 40-50mm.

In simple terms it is easier to control chromatic aberration with lesser powers and smaller objectives. This includes optics at all price levels.

Jerry

Rico70 · Jan 5, 2020

NDhunter said:
Henry, you have made a very good question, and the answer is yes, a higher magnification binocular is harder to make without chromatic aberrations.

So that means comparing an 8X as standard, a 10x, 12x and 15x and larger
will often have more chromatic aberrations.

You mentioned Nikon here, but it does not matter which brand.

Another thing which is important is the objective size, most of the time a smaller objective size, such as 30mm or smaller, will have less chromatic aberration than a larger sized objective such as 40-50mm.

In simple terms it is easier to control chromatic aberration with lesser powers and smaller objectives. This includes optics at all price levels.

Jerry, what do you want to support?
The AC is proportional to the focal ratio of the lens. And nor is it not easy to generalize between longitudinal and transverse AC.

Don't you agree you too to with some allegorical quotes that "the shoemaker should stick to his step"?

:t:

NDhunter · Jan 5, 2020

Rico70 said:
Jerry, what do you want to support?
The AC is proportional to the focal ratio of the lens. And nor is it not easy to generalize between longitudinal and transverse AC.

Don't you agree you too to with some allegorical quotes that "the shoemaker should stick to his step"?

:t:

I am not sure of your question, but my general statement above stands,
I was referring to the OP's question.

Jerry

Rico70 · Jan 5, 2020

tenex said:
This is exactly the point I've always made: any magnified view, even 7x, has added jitter handheld, and somehow the brain must learn to deal with it...

Unfortunately or fortunately, it is so! The human being is used to the 1x sight. Any higher value will cause discomfort or oddity. This is normal and must be taken into account, if the individual intent is to understand how to best solve the thing (use binoculars even with magnifications greater than 6x).
Experience is essential, in my opinion, to improve observations.

Troubador said:
Bino jitter or shake is not a simple subject.

I agree 100% ... the gusts of wind and the beating of the heart after a climb are all subjective events that influence differently every time. And that's why I don't take them into consideration when I discuss magnification, because their contribution is proportional to magnification and therefore indifferent to any magnification.
This Lee is a very important point of the matter. Too important not to accept it.

Rico70 · Jan 5, 2020

NDhunter said:
I am not sure of your question, but my general statement above stands,
I was referring to the OP's question.

Yes, but your answer was wrong! :t:

The right answer is that it is the focal ratio that determines the AC. Not the magnification nor the aperture (which depends on the cases).
We are not talking about telescopes, where the focal ratio is fixed and the magnification is variable with different eyepieces. But of binoculars, with calculation processes designed for fixed magnification (whether 2x or 100x).
Hence, the AC depends on the focal ratio of the project.

As for the allegory, if you haven't understood it, it's better this way.
The important thing is that you understand the technical part of AC.

Troubador · Jan 5, 2020

Rico70 said:
their contribution is proportional to magnification and therefore indifferent to any magnification.

Rico you seem to be contradicting yourself here.

If the bino shake is proportional to magnification (which it surely is) then how can it also be indifferent to magnification?

For practical birdwatching activities, the principal that bino shake is proportional to the magnification is too important not to accept it.

Lee

Rico70 · Jan 5, 2020

Troubador said:
Rico you seem to be contradicting yourself here.

If the bino shake is proportional to magnification (which it surely is) then how can it also be indifferent to magnification?

For practical birdwatching activities, the principal that bino shake is proportional to the magnification is too important not to accept it.

Hi Lee, I try to explain this.
If the contribution of wind and heart rate is proportional for each enlargement, there is no need to count it specifically (as you want to do). And therefore, that will not be a shake value that can modify the basic concept of shaky vision, more than other factors that determine movement.

When it is windy, will you use a 4x or will you continue to use the usual 8x?

If you answer 4x, you are consciously choosing to want to keep a vision as firm as possible at that particular moment, but always knowingly you will be satisfied with the least (proportionate) detail visible with 4x compared to 8x.
While if you answer 8x, it means that, as I said above, you do not put the wind or heart rate into account.

Why do you do it (as others do), every time you have to say that you personally prefer 8x to 10x or 15x (personal opinion and not technical comment on the enlargement)?

Have I been clearer?

From your question, I notice that there is little information on how things really are. And just seeing the Sun transiting the sky does not mean that the Sun is spinning around the Earth (which by the way the Earth seems flat

).

Steve C · Jan 5, 2020

The defining attribute of a binocular seems to be magnification. As such, changing magnification is bound to affect usage of the instrument as changing magnification changes many things.

One cannot disconnect the effects whatever shaking is inherent in a user to changing magnification. Trying to pin this down to specific factors, such as one change produces 2x, 3x or whatever seems a fool's errand to me.

For example I am 5'11" tall and weigh 220 pounds. I am 71 and have a non surgically repairable torn right rotator cuff. Whatever else about me that might contribute to my shake level is irrelevant to somebody else. We are all different in physical characteristics. We are all different in how quickly we will tire and begin to notice shake. For that matter any particular person may well show different shaking symptoms for one day to the next.

The idea that shake is related to magnification is useful information, but there are simply too many unique variables to attempt to pin it down to anything other than a broad generalization. This seems to me to be best left to general information and let each user choose for themselves the various binocular characteristics they prefer. It should be quite obvious that people will state what their preferences are. It simply is a matter of personal choice.

Troubador · Jan 6, 2020

Rico70 said:
Hi Lee, I try to explain this.
If the contribution of wind and heart rate is proportional for each enlargement, there is no need to count it specifically (as you want to do). And therefore, that will not be a shake value that can modify the basic concept of shaky vision, more than other factors that determine movement.

When it is windy, will you use a 4x or will you continue to use the usual 8x?

If you answer 4x, you are consciously choosing to want to keep a vision as firm as possible at that particular moment, but always knowingly you will be satisfied with the least (proportionate) detail visible with 4x compared to 8x.
While if you answer 8x, it means that, as I said above, you do not put the wind or heart rate into account.

Why do you do it (as others do), every time you have to say that you personally prefer 8x to 10x or 15x (personal opinion and not technical comment on the enlargement)?

Have I been clearer?

OK after reading your post and especially SteveC's final paragraph in post74 I think I see a little more clearly what you are saying.

Nevertheless while I am sure that there are many factors that create my own personal bino shake, I find it absolutely true that my bino shake affects the image I see with my binos more with a 10x bino than with an 8x bino. So if there is a strong and variable wind blowing I will use 8x rather than 10x.

You ask about my reasons to choose between 8x or 10x or 15x and there are usually several reasons for the choice. For more than 20 years I used 10x binos but after trying 8x I found this magnification more useful because of the wider field of view and greater depth of field. I use 10x in specific habitats and use 15x indoors on a tripod. My 15x bino is too big and heavy to carry when out walking because I usually also have a DSLR camera and two lenses, plus backpack with food and drink.

Lee

Kevin Conville · Jan 6, 2020

Steve C said:
A bit off topic I suppose, but for an improved hold;
-cup the binocular between your palms
-thumbs on cheekbones, wherever placement is comfortable
-index fingers on forehead, again wherever placement is comfortable
-middle fingers for focus
-last two fingers around the barrels of the binocular
-make it steadier still using this with a baseball style brimmed cap using the index finger over the bill. May not work too well with small hands on the latter point.

Don't laugh, it works

Good advice Steve.

I've have used this grip for maybe 15 years, and only this grip. For minis on up, it is superior.
Besides being much more steady, your thumbs act as light shields.

mpeace · Jan 6, 2020

Steve C said:
A bit off topic I suppose, but for an improved hold;
-cup the binocular between your palms
-thumbs on cheekbones, wherever placement is comfortable
-index fingers on forehead, again wherever placement is comfortable
-middle fingers for focus
-last two fingers around the barrels of the binocular
-make it steadier still using this with a baseball style brimmed cap using the index finger over the bill. May not work too well with small hands on the latter point.

Don't laugh, it works

Like Kevin I want to thank you Steve for posting this.

I was trying it at the weekend and found it to be helpful when needing a bit more stability.

I tried your specific technique which was most effective if a little uncomfy for my non-dextrous hands. But I found a variation that was comfy and still had an effect.

So I encourage others to try and you don't have to follow a particular technique, just apply the principal of fixing the motion of you hands (which are holding the binoculars) to the motion of your head through contact. Your head then stabalises your hands and therefore the binoculars.

Rico70 · Jan 7, 2020

Troubador said:
OK after reading your post and especially SteveC's final paragraph in post74 I think I see a little more clearly what you are saying.

I have to admit that Steve has been able to explain it much more effectively than me.

Troubador said:
Nevertheless while I am sure that there are many factors that create my own personal bino shake, I find it absolutely true that my bino shake affects the image I see with my binos more with a 10x bino than with an 8x bino. So if there is a strong and variable wind blowing I will use 8x rather than 10x.

This is a choice! And personal choices should never be discussed (they are like opinions). But I take this opportunity to repeat a point that I think can help you better understand it (maybe it helps others too), and that perhaps is not so simple to connect effectively.
Your eye (like everyone else's) has a visual acuity limit, which indicates your maximum ability to see the details.
Now, regardless of its exact or absolute value, anyone of us can overcome this limit using binoculars, where the magnification value defines that increase. For geometric reasons, an increase of at least 3x is necessary to make a leap forward in the detail view. This is the minimum necessary step. And then, raising this value to power (9x) will take you to a higher level of the vision of detail, which is physically impossible even to perceive with the naked eye.
This is the reason why with binoculars above 9x magnification, your eye will perfectly see the details of the shake, which your hands pass to the binoculars (hands, wind, heart, independently).

This can make you aware that with 10x there is the shake to see, but also that at the same time this hides the exact same shake with 8x binoculars (actually it only reduces it by 0.8x or 20%, but that's enough).

So everything becomes a matter of knowledge and then of consciousness.
Not seeing the shake does not mean that it is not there, but only that for some users it will be preferable to continue not to see it, using values lower than 9x, while for others it will be preferable for example to use 25x and see the more details it provides.

Personal needs and choices will be fundamental in any choice.

Steve C · Jan 7, 2020

Rico70 said:
I have to admit that Steve has been able to explain it much more effectively than me.

This is a choice! And personal choices should never be discussed (they are like opinions). But I take this opportunity to repeat a point that I think can help you better understand it (maybe it helps others too), and that perhaps is not so simple to connect effectively.
Your eye (like everyone else's) has a visual acuity limit, which indicates your maximum ability to see the details.
Now, regardless of its exact or absolute value, anyone of us can overcome this limit using binoculars, where the magnification value defines that increase. For geometric reasons, an increase of at least 3x is necessary to make a leap forward in the detail view. This is the minimum necessary step. And then, raising this value to power (9x) will take you to a higher level of the vision of detail, which is physically impossible even to perceive with the naked eye.
This is the reason why with binoculars above 9x magnification, your eye will perfectly see the details of the shake, which your hands pass to the binoculars (hands, wind, heart, independently).

This can make you aware that with 10x there is the shake to see, but also that at the same time this hides the exact same shake with 8x binoculars (actually it only reduces it by 0.8x or 20%, but that's enough).

So everything becomes a matter of knowledge and then of consciousness.
Not seeing the shake does not mean that it is not there, but only that for some users it will be preferable to continue not to see it, using values lower than 9x, while for others it will be preferable for example to use 25x and see the more details it provides.

Personal needs and choices will be fundamental in any choice.

Is there not a contradiction here? Maybe the translator is not quite accurate, which seems to be a problem with Rico's posts.

I feel the need to point out that any binocular, for any user is a holistic representation. There are many facets of this. The optics must suit the user, that includes magnification. The design and construction, the brand preferences, and the overall ergonomics. Among many others

Technical aspects can be designed and tested, resolution can be quantified, glass types and coatings can be designed to specific criteria. These are the quantifiable objective aspects.

What can't be quantified is how well the mechanical/optical instrument that is the binocular in the hand fits the entirely subjective desires of the user.

In optics choice the two cannot be separated. Maybe that is why there are so many different options.

WJC · Jan 7, 2020

Chromatic Aberration, which might cause the rational observer no trouble ... even if it was noticed, can drive many observers to distraction.

When I was with Captain’s, I developed a fairly accurate method for measuring chromatic aberration. If I do another bino book, it will be included. In the meantime, I will keep the process to myself. Why? Because I have learned that facts can’t hold a candle to the armchair optician with a burning opinion. And I have neither the time nor inclination to get into a BB stacking competition with a roving opinionator.

Bottom Line:

Stop wasting time trying to come up with a way to reduce CA in your current binocular. Because unless you are God, Merlin, or Harry Potter you are wasting your time and will fail.

To solve your chromatic aberration problem, 1) Dig a little deeper into your pocket (some people find wasting money makes them feel all warm and fuzzy. 2) Develop your personal—quantifiable—tolerance for CA, and hunt until you find a binocular that will fill that need. 3) Realize that aberrations are not independent of each other. Thus, when you reduce CA a level you can live with, you might be doing so at the expense of making two or three other aberrations ... worse.

One size does not fit all. :cat:

Cheers,

Bill

Chromatic aberration (1 Viewer)

Well-known member

Well-known member

Well-known member

reality-based

Moderator

"Experientia Docet”

Experienced observer

Well-known member

Experienced observer

Well-known member

Well-known member

Moderator

Well-known member

Well-known member

Moderator

yardbirder

Attachments

Well-known member

Well-known member

Well-known member

Well-known member

Similar threads

Users who are viewing this thread