
Originally Posted by
JHzlwd
Hi Christina,
I have seen this before, in film as well, but very rarely.
My theory is this ... Note the image is strongly divided into a very bright (over-exposed) and very dark region. Some lenses (the 105 mm Micro Nikkor, for example) have a rather large and almost flat back surface facing the sensor or film. It is my view that the very intense part of the image focused on the sensor can reflect from there onto that flat (ish) lens surface and appear as a weak ghost image elsewhere, especially in very dark parts of the image. With most lenses having a more curved back surface this ghost is highly out of focus so goes unnoticed, contributing only some flare.
This ghost should, however, be reversed from left to right which challenges my theory. That could be explained, perhaps, by an additional reflection within the lens which dominates. I'm on thin ice here for that reason ;-) It would be helpful knowing what lens you used so I could investigate further.
A perfect lens would never reflect any light off its elements but there is no such thing as perfection, advanced coatings notwithstanding.
Best wishes,
JH