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What is Meopta doing? (1 Viewer)
- Thread starter tenex
- Start date
Chosun Juan
Given to Fly
I have received an emergency call on the hotline that an 'International Incident' may be unfolding :eek!: and that my urgent assistance is required! o
While I am not a Physicist and some of the finer points of optical design seem like double dutch to me, I am pretty sure I can help sort this one out ..... :king:
Gentlemen - what we might have here is - "a failure to communicate" :-O https://m.youtube.com/watch?v=MPMmC0UAnj0
"Dielectric" is loosely defined as multiple alternating layers (in a dielectric mirror arrangement of high, juxtaposed to lower refractive index material to reinforce the interference pattern, and in anti-refection coatings to cancel it). Most commonly used in the Bragg configuration of 1/4 lambda, and up to 100 layers in narrow wavelength applications.
If I recall correctly, Zen-Ray had 40 layers, a lot of the Kamakura stuff consists of 64 layers, and Swarovski uses 70 layers (or more?) ....
Manufactures for sure would not be keen to publish their individual recipes, or even accurately numerically graduated reflectance curves. I recall Bushnell used to publish a numberless graph in some of it's marketing material, and about the best that could be hoped for is to know the number of layers ..... with the general American edict that if some is good, then more must be better !
As David mentioned earlier, 'protected' or even 'enhanced' metal mirrors (silver in this case) are or may be being used. I think it is this area of 'enhanced' silver mirrors that may have an additional 4 layers or more of some secret materials concoction of coatings that may fit the definition of "dielectric" coatings. My guess is that Meopta is talking about both silver AND dielectric coatings on the SAME mirrored surface of the prism. Ergo - you are both right !
Here is some interesting further reading for folks on mirrors, dielectric materials, and coatings.
https://www.photonics.com/a25501/Mirrors_Coating_Choice_Makes_a_Difference
https://www.rp-photonics.com/dielectric_mirrors.html
https://www.rp-photonics.com/dielectric_coatings.html
Hope that helps ! :t: :loveme:
Now if you'll excuse me, I have a plane to catch to the Korean peninsula ...... something about a 'minor' disagreement ??! there :cat:
Chosun :gh:
Graham Priest, Prof. Emeritus, Uni. of Melbourne,
on the principle of 'catuskoti' in Buddhist philosophy (link):
"It insists that there are four possibilities regarding any statement: it might be true (and true only), false (and false only), both true and false, or neither true nor false."
You need an Australian to explain these things.
Chosun Juan, thanks for those (other) links.
on the principle of 'catuskoti' in Buddhist philosophy (link):
"It insists that there are four possibilities regarding any statement: it might be true (and true only), false (and false only), both true and false, or neither true nor false."
You need an Australian to explain these things.
Chosun Juan, thanks for those (other) links.
CJ,
I mentioned back it #18 that I thought Meopta might use enhanced silver coating. Although that was part of my question to Meopta, I'm sure it will remain one of their little secrets. Both phase coating and the 'enhanced' bit are technically dielectric, even if it is rarely mentioned. No doubt, one way or another the Meostar prisms are dielectric coated. The real subject of the debate was whether the principle mirrored surface was silver coated. I think I got a clear answer on that.
A more interesting question is whether any other top manufacturers are keeping quiet about using silver as well? Looking at some of the transmission spectra it looks like it is a distinct possibility, but I'm sure they are not going to admit it. :-O
David
I mentioned back it #18 that I thought Meopta might use enhanced silver coating. Although that was part of my question to Meopta, I'm sure it will remain one of their little secrets. Both phase coating and the 'enhanced' bit are technically dielectric, even if it is rarely mentioned. No doubt, one way or another the Meostar prisms are dielectric coated. The real subject of the debate was whether the principle mirrored surface was silver coated. I think I got a clear answer on that.
A more interesting question is whether any other top manufacturers are keeping quiet about using silver as well? Looking at some of the transmission spectra it looks like it is a distinct possibility, but I'm sure they are not going to admit it. :-O
David
jape
Well-known member
its easy mate, turn off FB and phone, sit on verandah, grab a coldie, watch sunset, listen to kookaburras for a while, realise you are hanging upside down from bottom of planet but not falling off .... then it all comes clear!
On Schmidt-Pechan mirror coatings.
Walter E. Schoen in Astronomie.de: post #249103, July 23, 2005.
Translated by Google.
"There are virtually no details in the literature (eg in physics or especially in optics textbooks), as each manufacturer keeps his secrets for himself and often even waives patenting, because this would result in a disclosure..."
Walter E. Schoen in Astronomie.de: post #249103, July 23, 2005.
Translated by Google.
"There are virtually no details in the literature (eg in physics or especially in optics textbooks), as each manufacturer keeps his secrets for himself and often even waives patenting, because this would result in a disclosure..."
Chosun Juan
Given to Fly
LOL. 3
:t:Jape you know all about this (though you have let the side down, et tu Chosun Juan): [Link]
But I bring it up here to use this chance to promote it.
Though not an Australian I have always (since I first understood maps as a kid) been a proponent of this.
Also aesthetically to me so much prettier than "North-Up", more so the "Physical" (i.e. contra Political) maps with greens and browns.
But I bring it up here to use this chance to promote it.
Though not an Australian I have always (since I first understood maps as a kid) been a proponent of this.
Also aesthetically to me so much prettier than "North-Up", more so the "Physical" (i.e. contra Political) maps with greens and browns.
Chosun Juan
Given to Fly
Hi David,
Yes, even the change from Silver to Enhanced Silver coatings on the mirror would explain the differences people are seeing.
I have no doubt that both the people communicating with you and Gijs were explaining things truthfully as they understood them. Between definitions, perceptions, and 'transmission losses' in the communication chain :-O we arrive at the somewhat imprecisely defined present story that has been conveyed.
I think your conclusion is correct - the mirror is a silver based dielectric coating. We aren't of course privy to how many 'enhancement' layers on top of the protected silver coating it takes before it constitutes a dielectric coating. That I imagine is information that all manufactures would like kept on the down low. I recall that when the high end Brunton Icon binocular was in production it had what was termed AL+ mirror coatings.
You raise an interesting point as to how many other manufacturers are using silver based (enhanced) coatings and calling them dielectric. I agree with what you've said - the transmission spectra of some other bins indicate that Meopta is not the only one ! and yes I doubt those brands are keen to let that particular cat out of the bag :cat:
Chosun :gh:
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Chosun Juan
Given to Fly
Is it just me - or does he have an uncanny resemblance to Borat ?!! 3
Chosun Juan
Given to Fly
If only it were that simple ! :-O
It seems to be just a case of imprecise definitions, narrow focus, and isolated communications ....... snafu !! 3
Thanks for the link - fascinating stuff :t:
Chosun :gh:
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Chosun Juan
Given to Fly
Adhoc, I think things have progressed a bit since then, from the back rooms populated by propeller heads, to industry supply chains, and even into the public domain. See the links in my initial post to see some of the materials widely in use. Even this Wiki entry contains some of the common materials https://en.m.wikipedia.org/wiki/Optical_coating
With the properties of various common and economically viable materials known, and given the integer fractions of wavelengths thicknesses employed, I'm sure that computer simulation programs exist that could accurately predict the resultant reflectance values and hence colour spectra of any particular concoction or proposed proprietary recipe that the designers would like to dream up. Such calculations would be a lot easier than Computational Fluid Dynamics (CFD) which is now an essential part of the F1 aerodynamics development concept, design, and pre-manufacturing cycle.
This article is a summary of the now decades old MIT research on 'perfect mirrors' http://news.mit.edu/1998/mirror
Chosun :gh:
Gijs van Ginkel
Well-known member
Chosun,
Thank you for your humorous and informative intervention to prevent WW-3.
Gijs van Ginkel
Thank you for your humorous and informative intervention to prevent WW-3.
Gijs van Ginkel
jape
Well-known member
WW3 has been ongoing for a couple of decades! the illuminati just havent decided (now trump is leaving korea alone for a bit as they kiss and make up) whether WW4 will be the iran/israel conflict or a bit later in europe. i think they need to harvest a few more souls to feed on via anal orifice in their flying saucers first.
people will insist on tinfoil hats (and naturally get laughed at) when it should be tinfoil underwear. decent diaelectric coated chainstore undies would resolve most present conflicts by cutting off harmful rays caused by mobile phones to the sensitive bits and dispersing the emotional reactions caused by subconscious tingles.
dries1
Member
dries1
Member
Regarding Meoptas costings, there is something being done to the coatings.
Meopta 8X42 B1 serial 12xxxx
Meopta 8X42 B1 serial 15xxxx
There is a difference, while I have the later serial # in for service (focus wheel) when it gets back I need to do a more advanced comparison. Meopta is definitely doing something with the coatings. There was a thread earlier on this discussing the 7X42 since 2005 to present regarding coatings.
Regardless of silver+dielectric I could careless about the formula. They are without a doubt the best mid range glass out there in 8X42, they are a much better glass than the Nikon MHG, which after viewing those for a while have major pincushion distortion when panning.
Andy W.
Meopta 8X42 B1 serial 12xxxx
Meopta 8X42 B1 serial 15xxxx
There is a difference, while I have the later serial # in for service (focus wheel) when it gets back I need to do a more advanced comparison. Meopta is definitely doing something with the coatings. There was a thread earlier on this discussing the 7X42 since 2005 to present regarding coatings.
Regardless of silver+dielectric I could careless about the formula. They are without a doubt the best mid range glass out there in 8X42, they are a much better glass than the Nikon MHG, which after viewing those for a while have major pincushion distortion when panning.
Andy W.
tenex
reality-based
Thanks for your help in coming to this conclusion. It's finally making sense to me. (Thanks also to David for pointing out privately that concerns about oxidation of silver [based?] coatings are easily exaggerated.)
I do wish it were possible to ask and answer questions like this without stumbling into old arguments about what one should worry about and what's good enough for whom and so on... it's only a matter of information. What we choose to do with it is up to each of us.
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Gijs van Ginkel
Well-known member
tenex, post 77,
A polished silver layer exposed to air oxidizes very quickly, it turns black (basic high school chemistry). When kept under a nitrogen atmosphere in a roof prism binocular the chances are very small that this occurs. It becomes almost zero, when the silver layer is protected by a spectrally neutral transparent layer. Nevertheless it sometimes occurs as I found out with older binoculars which needed to be repaired for that reason. But that is no reason for concern, since it very rarely occurs.
Gijs van Ginkel
A polished silver layer exposed to air oxidizes very quickly, it turns black (basic high school chemistry). When kept under a nitrogen atmosphere in a roof prism binocular the chances are very small that this occurs. It becomes almost zero, when the silver layer is protected by a spectrally neutral transparent layer. Nevertheless it sometimes occurs as I found out with older binoculars which needed to be repaired for that reason. But that is no reason for concern, since it very rarely occurs.
Gijs van Ginkel
Gijs,
a question in this respect:
I remember having read in one of the optics books (I have not yet been able to find that quote again) that dielectric coating in a roof prism, with its higher reflectivity, would usually lead to more brightness in the image, but that silver coating would actually still provide the better contrast (the Meoptas show very good contrast in my view).
Do you have an opinion on this?
Canip
a question in this respect:
I remember having read in one of the optics books (I have not yet been able to find that quote again) that dielectric coating in a roof prism, with its higher reflectivity, would usually lead to more brightness in the image, but that silver coating would actually still provide the better contrast (the Meoptas show very good contrast in my view).
Do you have an opinion on this?
Canip
Gijs van Ginkel
Well-known member
Canip, post 79,
No I do not have an opinion about it.
Gijs van Ginkel
No I do not have an opinion about it.
Gijs van Ginkel
