Raimo wrote:
> BTW do you have any information about Canon using plastic elements in SLR
> lenses in the ´seventies?
Actually, it wasn't a plastic element that caused all the controversy. It
was a plastic band that wrapped around the circumference of several (two or
three) elements to hold them together. One of the elements was fluorite,
which doesn't bond well with glass but which Canon still uses in its
telephotos. It's a super-low-dispersion synthetic crystal that corrects
chromatic aberration in telephotos.
I'm sorry I can't tell you exactly which lens it was. I used to know but I
can't seem to call the information out of the gray-matter "files." <s>
In those days, just the fact that Canon had used plastic _in_ the lens was
enough to cause controversy; the story got going that one of the "elements"
was plastic, that Canon lenses were therefore unacceptably cheap, etc., etc.
It was all rumormongering.
In those days, the French cine lens manufacturer Angieneux was making and
marketing one 35mm camera lens per year as a sort of vanity project. They
used a certain kind of polycarbonate for the lens barrel, and published an
elaborate argument as to why it was a superior material for lens barrels
vis-a-vis metal--better thermal stability, lighter weight, didn't dent,
etc.--but the public was having none of it. The lenses didn't achieve the
reputation Angieneux had hoped (although they were very good--for a while
they were the best zooms you could buy, and helped show the way for some of
the camera manufacturers to make better zooms), so it got out of the lens
business.
--Mike
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