Is it a well-known phenomena, or is it just my eyesight?

[Arkteia]

I always had very sharp eyesight that comes with being naturally far-sighted. What was a blessing in my younger years turned into a hazard. My eyesight is probably +1.5 to +2 and I should wear eyeglasses but often forget to put them on.
Here is an interesting phenomena I have noticed: when I have my glasses on, my gems appear brighter and more colorful. What is it? At first, I thought, OK, the alex is almost emerald cut and obviously optically enlarging the facets makes color shift more noticeable. But what about other rings? My ruby looks crisper, too.
Does it have to do with the light being refracted three times, at the lens front surface, at the back, and then the eye? Or something else is going on?
The main reason I am asking this question is because we loupe the stones and the loupe works as eyeglasses. I wonder if colors look slightly different under a loupe. Also, could different people perceive colors in a different way because of their vision?

 

[velouriaL]

I have decent vision and aI have am just a little bit nearsighted, but I know that whole world looks more vibrant and colorful when I put my glasses on...

 

[empress]

Are your glasses coated? Many "clear" lenses are.

 

[PinkTower]

I have decent vision and aI have am just a little bit nearsighted, but I know that whole world looks more vibrant and colorful when I put my glasses on...

Well, I am farsighted, +3, and my stones look brighter when I have my glasses or contacts on, too!!!

 

[BoulderGal]

I've worn glasses since I was a toddler, and have always noticed slight variations in color with and without my glasses. I chalked it up to either 1) I can see more clearly, so things aren't blurred together or 2) slight bending of light as it goes through the glasses and then my own lens. I'm farsighted with astigmatism.

Interestingly, a year ago, I had cataract surgery in both my eyes (I was only 41 at the time, lucky me ) . My new lenses have a UV coating built in and the only thing I notice is that the green in LED traffic lights is a very slightly bluer than before. My eyes were done one at a time, so I had two weeks to compare.

 

[MakingTheGrade]

When they design good loupes, they makes sure the curvatures of the lenses don't affect the colors..or at least I remember reading that.

 

[VapidLapid]

Magnification does not affect brightness. magnified or not the object (in this case your stone) with all other factors unchanged, is reflecting the same number of photons. Psychologically it may seem brighter but it is not. Think how fast the energy crisis facing the world would be solved if we could amplify energy simply with magnifying lenses. However, the magnifying effect of your glasses projects the image of your stone over a larger surface area of your retina (hence looks bigger). This means that more color sensing rods and cones are stimulated, and so the colors may seem more intense or nuanced.

 

[desertgem]

Vision and sight ( seeing) are different. Vision is the photochemical reactions that occur in the receptor cells of the retina when hit with the responsive color with enough intensity to fire a neuron. People with certain degrees of "color-blindness" can have problems here distinguishing color. Once the nerve impulse leaves via the optic nerve, it is converted into "images" by the brain which usually contain color. Since this is a brain function, the brain can do alterations on how this is interpreted. So some see brighter or dimmer colors and difference in shades between individuals is relative. The sharper the image is, the brighter the color is interpreted, so this might be a reason. A parent might see their child as pretty/handsome, whereas others would not. Or see a ruby as red rather than pink . The old saying, you buy pink sapphires and sell rubies. Sorry, I will stop the lecture mode there

Jim

 

[chrono]

My guess is that with your glasses, because you can now focus properly on the gem, it appears clearly, hence (to your eye and mind), the colour is sharper and brighter.

 

[zeolite]

Magnification does not affect brightness. magnified or not the object (in this case your stone) with all other factors unchanged, is reflecting the same number of photons. Psychologically it may seem brighter but it is not. Think how fast the energy crisis facing the world would be solved if we could amplify energy simply with magnifying lenses. However, the magnifying effect of your glasses projects the image of your stone over a larger surface area of your retina (hence looks bigger). This means that more color sensing rods and cones are stimulated, and so the colors may seem more intense or nuanced.

If you double the image size of a gem with a 2X loupe, you are spreading the same amount of light over 4 times the area. The brightness is reduced to one quarter. If the brightness were the same, your loupe would have to be creating 4 times as much light, which it can't do. I've noticed that the color of pastel gems seem better under a loupe, because the light per unit area is being decreased.

From this link:

http://www.themcdonalds.net/~themcdo/richard/index.php?title=Understanding_Magnification

See this: Photographers with single-lens reflex cameras know that, when they double the focal length of their lens, the image gets dimmer so they have to double the exposure too. The same is true with your telescope. When you raise the magnification, the image gets dimmer. This means that selecting the right magnification to view a given object will often involve making trade-offs.

 

[Largosmom]

Do you have an anti-glare coating or other coating on your lenses? Perhaps that changes the colors some when you have your glasses on, or perhaps since the light coming into your eye from the gemstone is better focused on your retina, you perceive there to be "more" light than previously.

Laura

 

[VapidLapid]

Magnification does not affect brightness. magnified or not the object (in this case your stone) with all other factors unchanged, is reflecting the same number of photons. Psychologically it may seem brighter but it is not. Think how fast the energy crisis facing the world would be solved if we could amplify energy simply with magnifying lenses. However, the magnifying effect of your glasses projects the image of your stone over a larger surface area of your retina (hence looks bigger). This means that more color sensing rods and cones are stimulated, and so the colors may seem more intense or nuanced.

If you double the image size of a gem with a 2X loupe, you are spreading the same amount of light over 4 times the area. The brightness is reduced to one quarter. If the brightness were the same, your loupe would have to be creating 4 times as much light, which it can't do. I've noticed that the color of pastel gems seem better under a loupe, because the light per unit area is being decreased.

From this link:

http://www.themcdonalds.net/~themcdo/richard/index.php?title=Understanding_Magnification

See this: Photographers with single-lens reflex cameras know that, when they double the focal length of their lens, the image gets dimmer so they have to double the exposure too. The same is true with your telescope. When you raise the magnification, the image gets dimmer. This means that selecting the right magnification to view a given object will often involve making trade-offs.

The relationship of Clear Aperture (diameter of lens) and Numerical Aperture is the determining factor in illumination not magnification. If you double the image size with a 2x loupe but your 2x loupe collects light over a larger surface area you may brighten your image. This is why telescopes keep getting larger to be more sensitive. The lenses of my glasses (and my loupe) have a significantly greater collecting surface than my eyeballs. When I look at the world with or without my glasses, the brightness of the world does not change. Photographers with single lens reflex cameras know that regardless of magnification, making the (numerical) aperture smaller will make the image dimmer, making the NA larger will make it brighter (assuming exposure is unchanged). View camera users are another story; they do know they have to compensate, adding a stop to exposure, with each doubling of the focal distance greater than twice the focal length of the lens system. Most SLRs do not have rails that allow for the extension of the lens much beyond its focal length. Some did, like the medium format Rollei66 which had optional bellows rails that allowed the lens to be extended, and they even had reversal rings to the lens could be mounted backwards for extreme close ups.

 

[chrono]

As much as I’d love to pretend I understood even a single sentence that VL and Zeolite have written, I have absolutely no clue. Everything just zoomed over my head.

 

[Michael_E]

The main reason I am asking this question is because we loupe the stones and the loupe works as eyeglasses. I wonder if colors look slightly different under a loupe. Also, could different people perceive colors in a different way because of their vision?

Yes, definitely, some people see things differently depending on their glasses or loupe. The attached picture show the sort of glasses that I normally wear and I have never seen a trace of gray or brown in any gem. As for brightness, well part of that depends on the size of ones glasses or loupe and part of it depends a person's disposition. Large glasses not only give greater light gain, but the pink color and heart shape create a brighter disposition. Try these and you'll be amazed at how your vision and outlook improve!

 

[zeolite]

Numerical aperture is defined here:

http://en.wikipedia.org/wiki/Numerical_aperture
It is applied to fiber optics and microscopes (and not to cameras), both of which collect light from extreme wide angles, which is not the case here.

F-number, which is applicable to this discussion, is defined here:

http://en.wikipedia.org/wiki/F-number
The f-number defines a solid angle of light; useful for comparing lenses

Quoting from this link, under Notation:
Doubling the f-number increases the necessary exposure time by a factor of four.

Other types of optical system, such as telescopes and binoculars may have a fixed aperture, but the same principle holds: the greater the focal ratio, the fainter the images created (measuring brightness per unit area of the image).

If you double the image size with a 2x loupe but your 2x loupe collects light over a larger surface area you may brighten your image.
Lets assume that your loupe of whatever X (magnification) exactly covers the gemstone while being in perfect focus. If you collect light from a larger surface, you are collecting white light from the white background around the gem. The gem is not getting any brighter, because you getting the same amount of light through the gemstone as before. You are merely adding extra white light from around the gem, which is not doing you any good.

View camera users are another story; they do know they have to compensate, adding a stop to exposure, with each doubling of the focal distance greater than twice the focal length of the lens system. If you double the focal length, you add two stops (4 times) as much light to the exposure. This is known in physics as the inverse square law.

Most SLRs do not have rails that allow for the extension of the lens much beyond its focal length.
This is done to focus closer, to get a larger image. Rails are not needed if you have macro lens, which can focus very close.

and they even had reversal rings to the lens could be mounted backwards for extreme close ups.
This changes the lens effective focal length, again not needed if you use a macro lens.

 

[Largosmom]

Ahhh, rubelite colored glasses!

sorry, but the technical discusion on optics is also passing me by.

 

[VapidLapid]

http://mysite.du.edu/~jcalvert/optics/lumens.htm

"Brightness in Images

We have now defined the four main illumination quantities: F, I, E and B, and given the connections between them. It is good to remember that I = dF/dΩ, E = dF/dA and B = d2F/dAdΩ. We will now look at some important properties of the illuminance of images formed by optical systems. In optics texts, this is usually called "brightness," but we have explained above why this term has been generally replaced by "luminance." The argument can be made rigorous, but we shall be satisfied with a simple demonstration that emphasizes the principal facts.

As shown in the diagram, a lens L forms an image I of an object O. dA and dA' are elements of an extended source and image. The rim of the lens is the entrance and exit pupil of the system, defining the extent of the pencil of rays that passes through it. Since the magnification y'/y = -s'/s, dA' = (s'/s)2 dA. The solid angle subtended by the entrance pupil at the object is Ω = πh2/s2, while the solid angle subtended by the exit pupil at the image is Ω' = πh2/s'2. Therefore, Ω'/Ω = (s/s')2. If B is the luminance of the object, and B' the luminance of the image, then the luminous flux in the input is BΩdA, while the luminous flux in the output is B'Ω'dA'. If there are no losses between source and image, these quantities must be equal, or BΩdA = B'Ω'dA'. This means that B'/B = (Ω/Ω')(dA/dA') = 1, or B' = B. The image luminance is equal to the object luminance.

The reason for this is clear. If the image becomes smaller, so that the same energy is concentrated in a smaller area, the solid angle under which it is illuminated increases proportionately, so the product remains constant. If the image is viewed by the eye so that the entrance pupil of the eye is full, the luminous flux entering the eye will be constant, equal to the image brightness times the solid angle subtended by the eye pupil.

If the image is formed on a diffusing screen, the same total luminous flux will come from a smaller area, which will appear brighter to the eye. A small image of the sun may ignite tinder if its temperature is raised enough, but this does not mean that the actual image has a greater luminance than the surface of the sun, but only that the energy comes from a larger solid angle.

The illumination in an image (not the luminance!) falls off for off-axis image points. If Ω is the solid angle on the axis, say A/s'2, the solid angle off the axis at an angle θ will be Ω' = (A cos θ)/(s'/cos θ)2 = Ω cos3θ. Since the illumination now falls obliquely at an angle θ, there is a further factor of cos θ. The illumination BΩ' = BΩ cos4θ. Therefore, the off-axis illumination falls off as cos4θ, which can be rather rapid. At only 20°, the illumination is off by 22%."

 

[Michael_E]

Ahhh, rubelite colored glasses!

sorry, but the technical discusion on optics is also passing me by.

Yes, and they aren't irradiated or heated!

The technical discussion is a bit irrelevant since all of the posters who are seeing an increased brightness offer evidence that it does appear to happen. I think that it's because sharper vision causes greater contrast between the dark and light areas that people see in a gem and since our eyes and brains "favor" the bright areas, the entire gem looks brighter...or not???