We know than an axial streak can be caused by a smudged lens that has been wiped in one direction. The following image shows both lens flare and a lens "streak." Sunset with lens flare and lens streak

But what could explain the one-sided streak in the following picture? I.e., why doesn't it flare/streak to both sides of the sun? (It was taken shortly after the first image above, by the same iPhone XS.) Half-streak


1 Answer 1


As you already suspected, it is most probably a partially smudged lens on that phone. It might also be a fingerprint just covering part of the lens. With tiny lenses, even the space between the ridges of a fingerprint can cause interesting effects.

You already had the right link there: What causes lens flare along specific axes?

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