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Camerart

LED light emission corona

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Hi, First post :)

I have noticed the light corona emitted from an LED.  What I am talking about is sparkle light, stars, surrounding the LED.  As I move my head away, it looks as though I'm zooming into the 'stars' and visa versa.  If I tilt my head sideways the corona also tilts in line with my eyes.

Is it cataracts, that is causing it?  Can it be photographed?

Cheers, Camerart.

Edited by Camerart

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Whether it can be photographed is easily checked by taking a photo.

Are you talking about this?

stn-a50k80-a6a-10b5m-24v-child-site-on.j

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Hi S,

Thanks for your reply. Your photo doesn't show enough detail for my next question.  I tried a photo using two different cameras, but neither was good enough to get the individual sparkles.

Following what I said in my first post, I wondered if the sparkles could be used in some sort of navigation, by comparing two different photos from different distances or angles?

C

Edited by Camerart

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24 minutes ago, Camerart said:

Hi S,

Thanks for your reply. Your photo doesn't show enough detail for my next question.  I tried a photo using two different cameras, but neither was good enough to get the individual sparkles.

Following what I said in my first post, I wondered if the sparkles could be used in some sort of navigation, by comparing two different photos from different distances or angles?

C

The effect is likely from the optics (eye or camera), so I doubt they can be used for navigation. Unlike the position of the light itself, the other optical effects will not necessarily have a fixed position or orientation.

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If the LED was actually a laser (as in a laser pointer) then you might be seeing laser speckle. But that is only where it is reflected from a surface, not around the light itself.

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22 minutes ago, swansont said:

The effect is likely from the optics (eye or camera), so I doubt they can be used for navigation. Unlike the position of the light itself, the other optical effects will not necessarily have a fixed position or orientation.

Hi S,

Your photo and my 2x photos, were giving me the impression, that it is unlikely to be useful, in this way.

 

I am a little puzzled, how my eye can see an image larger than the LED itself.  How is it possible?

C.

Thanks, C.

10 minutes ago, Strange said:

If the LED was actually a laser (as in a laser pointer) then you might be seeing laser speckle. But that is only where it is reflected from a surface, not around the light itself.

Hi S2,

Ok, thanks.

C.

Edited by Camerart

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35 minutes ago, Camerart said:

Hi S,

Your photo and my 2x photos, were giving me the impression, that it is unlikely to be useful, in this way.

 

I am a little puzzled, how my eye can see an image larger than the LED itself.  How is it possible?

C.

 

Do you mean why the halo is there, away from the LED? Light of different wavelengths behaves slightly differently, so you get chromatic aberration 

Chromatic aberration occurs because the lens refracts the various colors present in white light at different angles according to their wavelengths.  Red light, for example, is not refracted at the same angle as green or blue light so the focal point on the optical axis of the lens is farther away from the lens for red light.  Likewise, green light is focused closer to the lens than red light and blue light is focused in a plane that is closest to the lens.  This phenomenon is commonly referred to as dispersion and occurs to a certain degree in all spherically shaped lens elements.  The inability of the lens to bring all of the colors into a common focal plane results in a slightly different image size and focal point for each of the three predominant wavelength groups.  The result is a colored fringe or halo surrounding the image, with the halo color changing as the focal point of the objective is varied.

https://escooptics.com/blogs/news/84510147-chromatic-aberration-in-spherical-lenses

 

And your eyes may have some imperfections (natural/expected, and also some caused by disease) that exacerbate this.

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