| email@example.com writes:
|>Reportedly the line involved here was NOT energized and this is a case of
|>induction from a nearby line that was.
|>You can see the clear shape of the arc in the multiple reflections due to
|>the many glass elements in the lens, below the point of arc.
| Those "ghost images" of the arc are unlikely to be from reflections inside the
| images due to reflections are invariably a different size or distorted in
shape compared to
| the original (because they're reflected from curved surfaces).
| Instead, those images are probably generated in the CCD. Frame transfer CCDs
| electrons from light exposure for a period of 1/60 second, then rapidly shift
| of all of the pixels vertically into a non-light-sensitive storage area.
Then, over the
| next 1/60 second, the charges in the storage area are shifted out and
digitized one pixel at
| a time while the light-sensitive portion of the chip is accumulating the next
I've seen a few nearly same size reflections from lenses. There are many
layers often with no difference, but with an air gap, intended more for
correction of color.
Another possible source is reflection between front and back surfaces of
a lens filter in front.
| If there's no mechanical shutter, light that reaches the chip during the
| period ends up in the "wrong place" in the image, vertically offset from where
it ought to
| be. If the incoming light is continuous, it just causes a slight blurring
| transfer period is so short compared to the normal exposure period. But an
arc is very
| bright and very fast, so it could record an image that's both bright enough to
see and sharp
| despite the fact that the image is rapidly shifting across the CCD face.
| For further evidence, look at a still frame that has multiple "ghosts"
visible. Each one is
| a slightly different shape - because each is a separate arc that took a
| path through the air.
I'll look again.
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