You are mixing up 2 different things. The coatings on many of the early
SC lens designs have a yellowish reflection. This is normal and doesn't
change with age. Some of the earliest 50/1.4 and 55/1.2 lenses (but no
50/1.8s, I believe) had one or more lens elements using glass with a bit
of a radioactive rare-earth element in the mix to produce a then
otherwise unattainable refractive index and improved performance. A
byproduct of this, in addition to enough radioactivity to set off a
geiger counter, was that the glass acquired a yellowish cast over time
as a byproduct of the radioactive decay. Some other manufacturers had
the same problem.
The distinctions are that the rare earth lenses show a yellow cast when
you look through them, all early 50/1.4s show yellow reflections from
the surfaces and non rare earth lenses show no color cast when you look
through them.
Clear enough? (groan)
Moose
Thomas Haegin wrote:
I do have an old 1.4/50 serial 145xxx and an old
1.8/50 serial 887xxx. Both their coatings are
yellow-orange these days.
But I thought that's just how they always were? Are
you saying they kinda bleached out? If so, what WERE
the original colors of these coatings?? I wonder how
good anybody's memory still is on that after the 25+
years... :-)
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