[rollei_list] Re: Rollei 35S, SE

  • From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
  • To: <rollei_list@xxxxxxxxxxxxx>
  • Date: Wed, 3 Oct 2007 11:55:14 -0700


----- Original Message ----- From: "Marc James Small" <marcsmall@xxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Wednesday, October 03, 2007 11:32 AM
Subject: [rollei_list] Re: Rollei 35S, SE


At 01:36 PM 10/3/2007, Richard Knoppow wrote:
>


>   See the history of lens coating at the Vacuum Coater's
>site: http://www.svc.org/

Thank you, Richard.  Allow me just to say that
this version does not jive in details with most
of the accepted history, much of it derived from
the actual participants.  It is generally
dangerous to rely only on a single source.

Marc


msmall@xxxxxxxxxxxx
Cha robh bàs fir gun ghràs fir!

Well, there are other sources such as patent literature and stuff published in various scientific journals, for instance, the _Journal of the Optical Society of America_ and the afore mentioned _RCA Review_. Also, history accepted by whom? Also, history derived from the actual participants may simply mean anecdotal evidence. Also, who do you think wrote the history at SVC? Please keep in mind that the principles of anti-reflection coating were understood very early on, by Harold Dennis Taylor, for instance, and research into how to accomplish practical coatings were begun by him and continued by others. Vacuum coating technology was well known for other purposes than lens coating by the mid 1930's. I have no doubt that Smakula and others at Zeiss came up with vacuum coating but may not have been aware of work being done elsewhere. Also, I wonder if their coatings were "hard" in the sense of modern coating. The earlier method was to coat in the vacuum bell jar and then bake the coatings in air in a separate oven. Hard coatings are baked in the bell jar under vacuum, that makes the difference. I can find RCA patents going back to around 1940 showing this arrangement. Evidently Zeiss, or the German government, or somebody, decided not to patent or publish the work at Zeiss, sot its pretty hard to determine who was first. BTW, what patents did Zeiss have that anyone would be worried about infringing?

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
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