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Old Jul 3rd 2016, 04:07 PM   #1
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Types of lens flare - light and optical depth?

I'm trying to understand what's going on with lens flare in different kinds of lenses. There's a lot of lens flare out there creating weird and wonderful artifacts in people's pictures.

Without understanding the kind of lens flare going on in a very flat lens (e.g. smartphone) or a long lens, it's hard for me to understand footage such as this:
https://www.youtube.com/watch?v=DiawvnIz9-w

How does lens flare explain the circular artifact above the sun, in the footage? Without knowing the kind of lens being used in this footage, is it possible to posit a reasonable explanation?

Many thanks
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Old Jul 5th 2016, 06:05 PM   #2
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Just a guess.

I don't think the blue disc is due to lens flare.

I am guessing that that it might be a refraction phenomena,
A bit like a mirage, a mass of air at a significantly different temperature from the surrounding air could act as a lens, creating a second image of the sun.
This second image is much dimmer than the direct view of the sun.

It is possible that the blue colour of the disc is a camera artefact, as the camera tries to compensate for the vast over-exposure that would result from being pointed directly at the sun.
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Old Jul 7th 2016, 12:28 AM   #3
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Originally Posted by Woody View Post
I don't think the blue disc is due to lens flare.

I am guessing that that it might be a refraction phenomena,
A bit like a mirage, a mass of air at a significantly different temperature from the surrounding air could act as a lens, creating a second image of the sun.
This second image is much dimmer than the direct view of the sun.

It is possible that the blue colour of the disc is a camera artefact, as the camera tries to compensate for the vast over-exposure that would result from being pointed directly at the sun.
Thank you - I think you're right. I just found this footage, where it's been wobble compensated:


thus proving that it must be refraction as the smaller sun keeps shifting.

The idea I believe is that the lens is off centre (damaged?), or that a filter isn't placed on the camera correctly (e.g. cross threaded)

Last edited by curious123; Jul 7th 2016 at 12:32 AM.
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Old Nov 14th 2016, 11:10 PM   #4
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Lens flare is the light scattered in lens systems through generally unwanted image formation mechanisms, such as internal reflection and scattering from material inhomogeneities in the lens. All lenses will be subject to this to a greater or lesser degree, but this most commonly manifests with wider angles. A photographic lens that we see through and hold in our hand is made of numerous optical lenses put together in an arrangement. https://en.wikipedia.org/wiki/Lens_flare
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