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Age of my Optar lens?
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kthalmann



Joined: 24 Mar 2010
Posts: 1
Location: Oregon

PostPosted: Thu Mar 25, 2010 3:48 am    Post subject: Reply with quote

1banjo wrote:
hey
Going by Doug Kerr hypothesis I come up with this

"Wocoted" (big "C" surounding smaller "W") was first used in 1945
"Wocoated" lens starts about # 5xxxxx SO lets say
500000 1945
566667 1946
633334 1947
700001 1948
776668 1948
NOW I have a 23 Crown S# 706639 is a 1950 it has a {Optar S# 784566} & Graflok
833335 1950
900002 1951
966669 1952
A33336 1953
"Yellow Dot" lens (serial number A84258) pictured to approximately late 1953 or early 1954
B00003 1954
B66670 1955
C33337 1956
D00004 1957
C66671 1958
E33338 1959
F00005 1960

NOW this is baced on Doug Kerr 66,667 lenses per year

now 78ltd you say you have a 101mm F/4.5 Velostigmat in a non synch Rapax that is serial number 499171. It has the circle W mark for coating
that shows that there is some of then with (big "C" surounding smaller "W") before
the #5xxxxx AND that OK
now this I would say that your E56469 would be a 1959 BUT if your right F2 stamped on it's shutter to be June '62 then that would change the above list, would need some ajustment AND that OK too as we don't know !!
banjo


The hypothesis in Doug Kerr's post is actually mine, not his (as Doug clearly states). You can read the details on how I came up with it here.

Please note the numbers I used were specific to the time period for which I had a few known serial number vs. manufacturing date datapoints. Based on those known data points, I did a simple linear interpolation for the time period bounded by those dates. Even then, it's just a simple linear interpretation. I'm sure there were year-to-year variations in production quantities. It's just an approximation - and ONLY for the years stated.

Continuing that linear interpolation beyond the dates bounded by the known data is not valid. The decade following WWII was the heyday for most American large format lens manufacturers (Kodak, Goerz, Wollensak, etc.). By the mid-1950s, they were losing ground to the Germans - specifically Schneider (who had introduced the Symmar and Super Angulon lines by that time). By the mid-1960s, Kodak had ceased producing large format lenses. By the late 1960s, Goerz was bankrupt. The ownership of the Goerz name, trademarks and patents was purchased by Kollmorgen and then Schneider in the early 1970s.

I don't recall the exact date Wollensak left the business, but I believe it was around 1972. In any case, starting about 1955, Wollensak's annual production mumbers would have began to decrease dramatically, asymptotically approaching zero about 15 years later. To assume they continued to produce anything close 66,667 lenses per year after 1955 is simply not a valid assumption.

Kerry Thalmann
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1banjo



Joined: 16 Nov 2008
Posts: 478
Location: kansas

PostPosted: Thu Mar 25, 2010 5:02 pm    Post subject: Reply with quote

will
as you can see I stop at 1960 as they had all but stoped LF lens
there had move more to 35mm lens & movie camera lens as the market
had went. by about 1965 some where about then they were part of 3M
and had move more of there production to AV Market like reel to reel tape
recorder ,cassette tape recorder & Projectors {movie & slides} as the market
had move to Educational and in 1972 or 73 3M closed then down

banjo
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Dan Fromm



Joined: 14 May 2001
Posts: 1891
Location: New Jersey

PostPosted: Thu Mar 25, 2010 9:34 pm    Post subject: Reply with quote

Banjo, wishful thinking is a killer.
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