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Lens colors (1 Viewer)
- Thread starter Spartan J
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WJC
Well-known member
Usually, very little. Besides, AR coatings have no "color." What you are seeing is the "wavelength" reflected by that coating or the combination from multi-coatings. Multi-coatings usually transmit a bit more light. Will you see the difference? Probably not. :cat:
Bill
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WJC
Well-known member
Technically, "residual color" (nice-looking websites notwithstanding) is the result of not all VISUAL COLORS being corrected by the design (aperture, curves, spacings, and glass types) of the objective lens and has little or nothing to do with AR coatings. A two-element objective—even if well made—may leave a bit of a violet hue on one side of focus and yellow-green on the other. This is RESIDUAL color. :cat:
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Hi,
while there are certain differences in the color rendition of various binocular brands, the strong multicolored reflections sometimes seen on modern multicoated lenses are not the reason for them.
If these strong reflections were the reason for the differences in color rendition, the transmission curve would be quite low for the reflected wavelengths and the image through these bins would have a strong tint instead the observed slightly warm or cold color rendition.
Also please note that these reflections only occur at angles far from the optical axis - and multicoatings are tuned to perform only in the general direction of the optical axis.
There are some cheap bins which use strongly colored coatings at all angles for show effect (usually red) - these are not meant here and will show quite pronounced tints - apart from other aberrations...
Joachim
while there are certain differences in the color rendition of various binocular brands, the strong multicolored reflections sometimes seen on modern multicoated lenses are not the reason for them.
If these strong reflections were the reason for the differences in color rendition, the transmission curve would be quite low for the reflected wavelengths and the image through these bins would have a strong tint instead the observed slightly warm or cold color rendition.
Also please note that these reflections only occur at angles far from the optical axis - and multicoatings are tuned to perform only in the general direction of the optical axis.
There are some cheap bins which use strongly colored coatings at all angles for show effect (usually red) - these are not meant here and will show quite pronounced tints - apart from other aberrations...
Joachim
WJC
Well-known member
Many companies, including Zeiss, use different words and concepts when speaking to consumers than they do when speaking with engineers in-house or in other companies.
Just let me know if you wish to pursue this. Even when I had a contact there, it could take 3 or 4 days to get a response. After he retired, it could take a week or 10 days, with the virus ... who knows? Heck, I can’t even get a message through to my bank.
But, I respect you and if you require it of me, I will certainly do so. Although, I thought my explanation of metal deposits of less than 6 millionths of an inch to be adequate. :cat:
Cheers,
Bill
WJC
Well-known member
Hi, Pileatus,
In speaking with an optical friend about my situation of trying to help with too much on my plate. His response: “Why waste your time when this fellow can easily find answers on the Internet?” Admitting to myself that he was right, I find I should leave that research to you. If you are really interested, you will undoubtedly be pleased to find it for yourself.
That I not be a total quitter, I found the following to give you a leg up. Zenni Optical’s website states in part, concerning AR coatings (the bold letters are my doing):
“But first, let’s dispose of the most common misconception about AR coatings: that they tint the lens. This is not true. AR coatings are clear and colorless and invisible on the lens.”
Again, what people see as a colorful TINT on an objective lens is just certain wavelengths being reflected by those transparent/invisible deposits. Intuitive? Maybe not. Accurate? Without a doubt.
Cheers,
Bill
In speaking with an optical friend about my situation of trying to help with too much on my plate. His response: “Why waste your time when this fellow can easily find answers on the Internet?” Admitting to myself that he was right, I find I should leave that research to you. If you are really interested, you will undoubtedly be pleased to find it for yourself.
That I not be a total quitter, I found the following to give you a leg up. Zenni Optical’s website states in part, concerning AR coatings (the bold letters are my doing):
“But first, let’s dispose of the most common misconception about AR coatings: that they tint the lens. This is not true. AR coatings are clear and colorless and invisible on the lens.”
Again, what people see as a colorful TINT on an objective lens is just certain wavelengths being reflected by those transparent/invisible deposits. Intuitive? Maybe not. Accurate? Without a doubt.
Cheers,
Bill
Gijs van Ginkel
Well-known member
Billl, post 9,
You are fully correct and if anybody who believes that the blue color of the AR coatings on a lens works as a blue filter , that is to say make the lens itself have a blue color, could do a number of things
-1- read a proper textbook to be cured of this misconception
-2- Turn your binocular upside down above a crystal white piece of paper and you will see what color the optical glass will give that white surface and I have never seen a blue color coming up.
-3- unscrew the objective lenses from your binocular and look at a white surface through that lens. If that turns blue start to investigate what you had for dinner.
Gijs van Ginkel
You are fully correct and if anybody who believes that the blue color of the AR coatings on a lens works as a blue filter , that is to say make the lens itself have a blue color, could do a number of things
-1- read a proper textbook to be cured of this misconception
-2- Turn your binocular upside down above a crystal white piece of paper and you will see what color the optical glass will give that white surface and I have never seen a blue color coming up.
-3- unscrew the objective lenses from your binocular and look at a white surface through that lens. If that turns blue start to investigate what you had for dinner.
Gijs van Ginkel
Gijs van Ginkel
Well-known member
Binastro, post 14,
Yes you are right, I noticed that when we measured the transmission spectra of that type of lenses, but that does not mean that the glass itself is colored blue. With mushrooms you get a rainbow of colors, so that may be even more exciting. Stay healthy,
Gijs
Yes you are right, I noticed that when we measured the transmission spectra of that type of lenses, but that does not mean that the glass itself is colored blue. With mushrooms you get a rainbow of colors, so that may be even more exciting. Stay healthy,
Gijs
jan van daalen
Well-known member
Ah Gijs, since you seem to know that now I understand why you are such a colorfull person
Jan
Gijs van Ginkel
Well-known member
Jan, post 16,
And you know only a small part of my secret life.........
Gijs van Ginkel
And you know only a small part of my secret life.........
Gijs van Ginkel
I never said coatings had color or not and I do not appreciate the few who must constantly and annoyingly attack others.
Ed posted an excellent article...
Third paragraph begins with...
"To understand why coated lenses look colored, you have to understand what the coating is there for, and how it works."
People see things they correctly interpret as color. WHY they see what they see is always subject to inquiry.
Some come here to simplify pontificate, bloviate and bore many of us to death.
Have a great day!
Ed posted an excellent article...
Third paragraph begins with...
"To understand why coated lenses look colored, you have to understand what the coating is there for, and how it works."
People see things they correctly interpret as color. WHY they see what they see is always subject to inquiry.
Some come here to simplify pontificate, bloviate and bore many of us to death.
Have a great day!
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WJC
Well-known member
Hi, Pileatus,
That’s probably my fault; unintentional, I assure you. Your first post seemingly indicated AR coatings were of a certain “color.” That is a long standing idea which is just as wrong as it is intuitive. I had hoped to help correct your thoughts on the matter if I could.
When it comes to being undermined and attacked, you are talking to the poster boy. I have spent the last 17 years with a bull’s eye on my back.
When I mentioned a Navy convertible 7x50/9x63 on Cloudy Night, a “wannabe” optical expert indicated I didn’t know that I was talking about. Thus, I spent an inordinate about of time searching for a photo of this oddball binocular. I found one and posted it.
Sometime later, I mentioned the Japanese 6-inch binoculars that were in a waterproof “can” with a hatch to get into them. This same person challenged me on that, too [if, as an optical know-nothing you can challenge someone with credentials and experience, you can get your ego stroked by newbies and non-English speakers]. Fortunately, I had that image in my collection. Of course, I posted it.
Trying to protect my reputation from the attacks of this expert wannabe and preserve the integrity of their TOS—which he ignored with impunity—is why I was kicked to the curb.
One of their moderators shared with me:
“Not only is __________ a troll, he is a skillful troll.”
And, you have been on BirdForum long enough to remember when I was taken to task for saying Leupold didn’t MAKE binoculars. You may recall the huge amount of time it took for me to put that error to rest.
I realize that binocular forums are places for folks to share opinions. But you can’t drive nails with opinions. That why I’m into facts. When I share an opinion, it is usually labeled as such. Am I ever wrong? Of course, I am. I remember that time back in ’58. But cut me some slack ... I was only 7!!!
:eek!::-OSo, I know more about being attacked than I care to know. Thus, if I have been the source of any of your grief, I certainly apologize.
Bill
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