Richard Knoppow (dickburk@ix.netcom.com)
Sat, 20 Feb 1999 23:44:35 -0800
At 07:14 PM 2/20/99 -0800, you wrote:
>I found a objective from garbage sales.
>Kodak Fluro Ektar 111 mm. f : 1.5 Mag. 1 : 6 RA110 L
>Do you have any information about this obj.?
>
>Best Regards
>M.Umut Saraç
>
I don't have information on this specific lens but flourite elements are
used when unusually good chromatic correction is required. Flourite
combined with barium crown have virtually no secondary spectrum. It is
often used for microscope objectives.
The barrel shows a specific magnification ratio. Lenses without moving
elements can be optimized for only a single distance. For ordinary use the
loss of correction at other distances isn't too great, but where absolutely
the best possible performance is needed the distance is fixed. So, it would
seem this is a lens for some use which requires a 1:6 reduction or
magnification, needs to be exceptionally well color corrected and needs to
be very fast. It is also likely very well corrected for distortion at its
optimum magnification. Likely it was made for some application where it was
desirable to make measurements of the recorded images. If the lens were not
intended to be used wide open or nearly so it would not have been designed
with such a large aperture. In fact, its possibe the flour element or
elements were needed because of the speed.
I know Kodak made flour lenses for several purposes but can not find
specific reference to them, at least for the moment. The mounting
arrangement may give some clue as to how it was intended to be used. It is
likely to have been an expensive bit of glass (and calcium flouride) when
it was new.
Kodak serial numbers, starting about 1939, are date coded. The two
letters preceding the number indicate the last two numerals of the date.
The key word is C A M E R O S I T Y standing for 1, 2, 3, etc., so this guy
was made in 1951.
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
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