On Fri, Jul 19, 2002 at 06:05:44PM -0700, Winsor Crosby wrote:
> >In a message dated 7/19/02 4:20:04 PM Eastern Daylight Time,
> >hiwayman@xxxxxxxxxxxxxx writes:
> >
> >>OPTICAL CONSTRUCTION: 9 elements in 10 groups
>
> It is weird nomenclature anyway. There is only one group and eight
> individual ungrouped elements. Last time I looked a group involved
> more than one.
I guess the nomoclature has historic reasons. Before the invention of
lens coating, lens desinger really grouped several elements to one group,
to avoid flaire causing air/glass surfaces.
8 or 10 elements in 2 groups were a typical lens designs of this type.
Frieder Faig
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