[rollei_list] Re: Lens coatings and veiling flare.
- From: Marc James Small <marcsmall@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Thu, 09 Jul 2009 16:22:58 -0400
On 7/9/2009 4:06 PM, Richard Knoppow wrote:
While Marc beleives that Smakula, of Zeiss, invented hard coating I am
not so sure. Zeiss may have had this technology but the record seems
to show it was developed by a reseach group in the US during WW-2.
Vacuum coatings can be relatively soft and the early ones were. What
was developed here was the technique of baking the coatings in vacuo.
Previously the coated lenses were removed from the vacuum chamber and
baked in a separate operation. Baking in the coating chamber results
in coatings nearly as hard as the glass.
Richard
That is precisely the Smakula process. I can give you a cite to the
German technical journal where it was published in 1940, though I cannot
at present locate my photostat of the article. The New York Public
Library has a copy of the journal containing the article.
The Wollensak vacuum-coating process also produced hard coatings. The
coatings on their AA rangefinders routinely survived Fort Bliss dust
storms by late 1943, though the earlier versions as used during TORCH in
1942 were more vulnerable. I am not certain of the vacuum coatings used
by Ross in the UK and shared with Barr & Stroud for their military
optics, but, by 1945, these were certainly hard-coated. Whether that
was derived from US research or was independently developed, I know
not. As Ross and B&S are both now out of business, this might be hard
to run down, as I am not certain whether the corporate records of either
survived.
Marc
--
msmall@xxxxxxxxxxxx
Cha robh bàs fir gun ghràs fir!
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
in the subject field OR by logging into www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
'unsubscribe' in the subject field OR by logging into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
Other related posts:
