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Strange rays.
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PostPosted: Sat Aug 29, 2020 12:36 am    Post subject: Strange rays. Reply with quote
How can you explain the many subtle rays that come from a light source? Is it related to the lens design, the aperture, or something else? Who saw it. I never got that. Industiar-100U lens with helicoid, Sony NEX 5N camera.



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PostPosted: Sat Aug 29, 2020 1:17 am    Post subject: Reply with quote
I believe it is an effect produced by diffraction combined with residual spherical aberration.


PostPosted: Sat Aug 29, 2020 1:24 am    Post subject: Reply with quote
Gerald wrote:
I believe it is an effect produced by diffraction combined with residual spherical aberration.


Your opinion is highly appreciated by me. It is a pity that here you can not see those who design lenses. However, other lenses failed to perform this feat.


PostPosted: Sat Aug 29, 2020 1:50 am    Post subject: Reply with quote
The effect you captured is not so unusual. It is called a "star effect". A good article on this subject:
https://www.bhphotovideo.com/explora/photography/tips-and-solutions/create-compelling-star-effects-sun-stars-starbursts-photos


PostPosted: Sat Aug 29, 2020 3:05 am    Post subject: Reply with quote
Gerald wrote:
The effect you captured is not so unusual. It is called a "star effect". A good article on this subject:
https://www.bhphotovideo.com/explora/photography/tips-and-solutions/create-compelling-star-effects-sun-stars-starbursts-photos


The article is informative, but there are questions. Images of light sources in the sharpness zone are given in the article. There are specific forms of radiation of the stars. In my case, the light is completely unfocused, the shape is not a ray star, it resembles a circle with thin lines coming out of it. In addition, the lens did not close its aperture. One can temporarily accept the General nature of the phenomenon and as a special case of a particular lens.


PostPosted: Sat Aug 29, 2020 6:06 am    Post subject: Re: Strange rays. Reply with quote
LLB! wrote:
How can you explain the many subtle rays that come from a light source? Is it related to the lens design, the aperture, or something else? Who saw it. I never got that. Industiar-100U lens with helicoid, Sony NEX 5N camera.

This can be a result of either internal reflection or dispersion. Or both.

For example a scratched (for full 360°) front element can disperse light in a similar fashion.
Just as the one without properly blackened edges (the edge cut is the deepest scratch there is).


PostPosted: Sat Aug 29, 2020 6:34 am    Post subject: Re: Strange rays. Reply with quote
aidaho wrote:
LLB! wrote:
How can you explain the many subtle rays that come from a light source? Is it related to the lens design, the aperture, or something else? Who saw it. I never got that. Industiar-100U lens with helicoid, Sony NEX 5N camera.

This can be a result of either internal reflection or dispersion. Or both.

For example a scratched (for full 360°) front element can disperse light in a similar fashion.
Just as the one without properly blackened edges (the edge cut is the deepest scratch there is).


mmm.. The lens is brand new, bought directly from the factory about five years ago. No scratches. However, your thoughts accompany mine more than.


PostPosted: Sat Aug 29, 2020 7:59 am    Post subject: Reply with quote
Well oof highlights are sharp projections of the lens aperture opening in the image, so small imperfections in the aperture circle could cause diffraction with very strong highlights.


PostPosted: Sat Aug 29, 2020 9:25 am    Post subject: Reply with quote
D1N0 wrote:
Well oof highlights are sharp projections of the lens aperture opening in the image, so small imperfections in the aperture circle could cause diffraction with very strong highlights.


Clear. But the aperture didn't work. Its blades did not participate in the creation of the image. The lens was completely open, meaning the hole was round.


PostPosted: Sat Aug 29, 2020 9:53 am    Post subject: Reply with quote
LLB! wrote:
D1N0 wrote:
Well oof highlights are sharp projections of the lens aperture opening in the image, so small imperfections in the aperture circle could cause diffraction with very strong highlights.


Clear. But the aperture didn't work. Its blades did not participate in the creation of the image. The lens was completely open, meaning the hole was round.


There is always an aperture of not the blades than the ring the blades are behind. At certain angles small imperfections can have large effect.


PostPosted: Sat Aug 29, 2020 10:08 am    Post subject: Reply with quote
D1N0 wrote:
LLB! wrote:
D1N0 wrote:
Well oof highlights are sharp projections of the lens aperture opening in the image, so small imperfections in the aperture circle could cause diffraction with very strong highlights.


Clear. But the aperture didn't work. Its blades did not participate in the creation of the image. The lens was completely open, meaning the hole was round.


There is always an aperture of not the blades than the ring the blades are behind. At certain angles small imperfections can have large effect.


Theoretically, YES. But to get to these irregularities, the light beam must change direction two or three times. Although as clearly stated in the literature, an unsuccessful frame design can reduce the quality of optics by up to 40% down. The second argument is indisputable - this lens is built to work in a magnifier where the light flow goes in one direction. The reverse course is not provided.


PostPosted: Sat Aug 29, 2020 9:41 pm    Post subject: Re: Strange rays. Reply with quote
LLB! wrote:
aidaho wrote:
LLB! wrote:
How can you explain the many subtle rays that come from a light source? Is it related to the lens design, the aperture, or something else? Who saw it. I never got that. Industiar-100U lens with helicoid, Sony NEX 5N camera.

This can be a result of either internal reflection or dispersion. Or both.

For example a scratched (for full 360°) front element can disperse light in a similar fashion.
Just as the one without properly blackened edges (the edge cut is the deepest scratch there is).


mmm.. The lens is brand new, bought directly from the factory about five years ago. No scratches. However, your thoughts accompany mine more than.

I have a round cut from LASIK on both of my lenses now and if you point a high-beam directly into my eye, this is exactly the aberration I will see.
I believe any 360° dispersion or reflection source will do the job.


PostPosted: Sat Aug 29, 2020 10:05 pm    Post subject: Re: Strange rays. Reply with quote
LLB! wrote:
aidaho wrote:
LLB! wrote:
How can you explain the many subtle rays that come from a light source? Is it related to the lens design, the aperture, or something else? Who saw it. I never got that. Industiar-100U lens with helicoid, Sony NEX 5N camera.

This can be a result of either internal reflection or dispersion. Or both.

For example a scratched (for full 360°) front element can disperse light in a similar fashion.
Just as the one without properly blackened edges (the edge cut is the deepest scratch there is).


mmm.. The lens is brand new, bought directly from the factory about five years ago. No scratches. However, your thoughts accompany mine more than.


No scratches, but you are not taking into account the internal design of the lens, everything in the light path other than the lens elements themselves. There are plenty of things for the light to reflect off of or diffuse from inside the tube itself, even if coated matte black to minimize internal reflections.


PostPosted: Sat Aug 29, 2020 10:43 pm    Post subject: Reply with quote
It is very important to understand that the rays that seem to emanate from the light source are just a visual effect caused by diffraction! In a sense, these "rays" are an optical illusion! These rays do not necessarily have a physical existence.

The light waves diffracted by the discontinuities of the lens (iris diaphragm and the edges of the optical elements) interfere with each other so that for certain angles the interference is constructive. The "rays" as seen in the photograph basically show the angles for which the interference of the diffracted waves is constructive.

I believe that there is nothing magical or special about the Industar 100U regarding the observed star effect, which nevertheless requires an appropriate combination of factors (relative intensity of the light source, lens aperture, framing, exposure, etc. ) to be visible in a photo.


PostPosted: Sun Aug 30, 2020 12:52 am    Post subject: Re: Strange rays. Reply with quote
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Last edited by Blazer0ne on Tue Feb 22, 2022 7:09 pm; edited 1 time in total


PostPosted: Sun Aug 30, 2020 1:21 am    Post subject: Reply with quote
This is with an Angenieux projection lens, no aperture.



PostPosted: Sun Aug 30, 2020 1:34 am    Post subject: Reply with quote
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Last edited by Blazer0ne on Tue Feb 22, 2022 6:47 pm; edited 1 time in total


PostPosted: Sun Aug 30, 2020 6:53 am    Post subject: Reply with quote
Gerald wrote:
It is very important to understand that the rays that seem to emanate from the light source are just a visual effect caused by diffraction! In a sense, these "rays" are an optical illusion! These rays do not necessarily have a physical existence.

The light waves diffracted by the discontinuities of the lens (iris diaphragm and the edges of the optical elements) interfere with each other so that for certain angles the interference is constructive. The "rays" as seen in the photograph basically show the angles for which the interference of the diffracted waves is constructive.

I believe that there is nothing magical or special about the Industar 100U regarding the observed star effect, which nevertheless requires an appropriate combination of factors (relative intensity of the light source, lens aperture, framing, exposure, etc. ) to be visible in a photo.


I am inclined to the specifics of the lens body, not the glasses, and to the fact that the bright light goes in the opposite direction.


PostPosted: Sun Aug 30, 2020 9:37 am    Post subject: Reply with quote
I was easily able to replicate this with a strong OOF light source (a usb led lamp) shining directly into the the lens that happened to be on my camera (Auto-Takumar 35mm 1:2.3 wide open). When you look at the sun or stars you see rays emitting/ spikes for the same reason. Diffraction effects.


PostPosted: Sun Aug 30, 2020 10:17 am    Post subject: Reply with quote
D1N0 wrote:
I was easily able to replicate this with a strong OOF light source (a usb led lamp) shining directly into the the lens that happened to be on my camera (Auto-Takumar 35mm 1:2.3 wide open). When you look at the sun or stars you see rays emitting/ spikes for the same reason. Diffraction effects.


My congratulations ! You really do it ! We are the Сhampions ! Please, turn on F. Mercury song !


PostPosted: Sun Aug 30, 2020 10:25 am    Post subject: Reply with quote
[quote="LLB!"]
D1N0 wrote:
I was easily able to replicate this with a strong OOF light source (a usb led lamp) shining directly into the the lens that happened to be on my camera (Auto-Takumar 35mm 1:2.3 wide open). When you look at the sun or stars you see rays emitting/ spikes for the same reason. Diffraction effects.


My congratulations ! You really did it ! We are the Сhampions ! Please, turn on F. Mercury song !
Diffraction Queen Of The Light. Or no ?


PostPosted: Sun Aug 30, 2020 4:26 pm    Post subject: Reply with quote
LLB! wrote:
Please, turn on F. Mercury song !


Or The Beatles' "Here Comes The Sun" Laugh 1


PostPosted: Sun Aug 30, 2020 4:54 pm    Post subject: Reply with quote
...

Last edited by Blazer0ne on Tue Feb 22, 2022 7:09 pm; edited 1 time in total


PostPosted: Sun Aug 30, 2020 9:16 pm    Post subject: Reply with quote
Gerald wrote:
LLB! wrote:
Please, turn on F. Mercury song !


Or The Beatles' "Here Comes The Sun" Laugh 1


There is only heaven and earth and between them man as the main jewel.javascript:emoticon('Friends')


PostPosted: Sun Aug 30, 2020 9:33 pm    Post subject: Reply with quote
LLB! wrote:
Gerald wrote:
It is very important to understand that the rays that seem to emanate from the light source are just a visual effect caused by diffraction! In a sense, these "rays" are an optical illusion! These rays do not necessarily have a physical existence.

The light waves diffracted by the discontinuities of the lens (iris diaphragm and the edges of the optical elements) interfere with each other so that for certain angles the interference is constructive. The "rays" as seen in the photograph basically show the angles for which the interference of the diffracted waves is constructive.

I believe that there is nothing magical or special about the Industar 100U regarding the observed star effect, which nevertheless requires an appropriate combination of factors (relative intensity of the light source, lens aperture, framing, exposure, etc. ) to be visible in a photo.


I am inclined to the specifics of the lens body, not the glasses, and to the fact that the bright light goes in the opposite direction.


Yes, it is about internal reflections and dispersion between the elements and/or after the last element in the lens.
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