Purple flare: Causes and remedies

Started Mar 1, 2013 | Discussions thread
Anders W
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Re: Excellent!
In reply to Surefoot, Mar 3, 2013

Surefoot wrote:

Anders W wrote:

Surefoot wrote:

Because of the very specific hue produced, and because you could block them with a color filter, at least this is what i think, otherwise i would see fully clipped orbs on my GF1 too.

OK. But then you haven't fully understood my explanation. I didn't block the reflections with a color filter. I used the filter to reduce the color-channel imbalance that I talk about in this post:

http://forums.dpreview.com/forums/post/50958004

The reflections appear purple not because they actually have that color if you could see them with your naked eye but because of the sensor characteristics I describe in the post I link to (color-channel pollution along with color-channel imbalance).

Ok i edited my post in the mean time to be more specific, i did read your explanation and i agree with you on the result, but i dont think this is the original cause. I highly suspect internal reflections on the rear side of elements, the aperture shaped orbs actually lead me to reflections against the front elements... Then the coatings will cancel most of the wavelenghts, but let through that specific one that plays foul with the sensor.

If that had been the case, the second of the two solutions I tried (purple filter) would have had no effect at all.

If it was just high incidence rays we would see color bleeding around the light source, but it's not the case,

Why would there necessarily be color bleeding around the light source if the purpleness is due to rays with a large angle of incidence?

we clearly see ghosts all around the frame. And if it wasnt a reflection i wouldnt get aperture shaped orbs with the sun (round-ish) as a point source...

Reflection is of course involved. Noone has denied that. The fact that it is reflections we are dealing with explains the effect of the polarizer in the second image of the OP. It also explains why the light can arrive at the sensor at a large enough angle of incidence for color-channel pollution to occur in spite of the fact that the lens is designed so as to avoid such angles for its normal optical path (flare and reflections aside).

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