On 6/16/2022 10:17 PM, Alan C wrote:
The problem is related to lack of Multi-coating on the rear element
which was absent on pre-digital lenses. More commonly this gives rise
to ghosting (back-and-forth reflections) when these old lenses are
used on digital camera because the sensors are much more reflective
than film. The difference between the Sigma 170-500 APO & the later DG
version is indicative.
I suspect that is a possibility, I suspect the "multicoated" lenses of
the day may not have been as multicoated on the rear element. I use
quite a few legacy glass and the A100/2.8 macro is the only one I've
noticed hot spots on, which is why I thought it might be related to the
FREE design and the flat rear element.
Anyway, according to John, the problem doesn't exist, so it's all good.
bill
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