[LargeFormat] aero ektar

[Richard Knoppow]

----- Original Message ----- 
From: "animal" <s.jessurun95@chello.nl>
To: <largeformat@f32.net>
Sent: Monday, July 28, 2003 11:36 PM
Subject: [LargeFormat] aero ektar


> Hello i,m new here and hope you can answer my question.I,m
looking for test
> data on a 7 inch 2.5 aero ektar lens.I,ve tried to locate
this on the web
> but had no luck so far.
> Thanks,simon jessurun,amsterdam,the netherlands
>
>
   About the only performance data I know of is the computer
analysis of the lens in
_Modern Lens Design_ Warren J. Smith, 1992, McGraw-Hill Book
Co. ISBN 0-07-059178-4
  The Aero Ektar is shown on p.345.
  The lens is covered by USP 2,343,627
  Reports from users over the last few years are variable.
Some get good performance, some complain of poor color
correction. The performance graphs shown in Smith indicate
the chromatic correction should be good. Its possible that
actual lenses have suffered from mechanical damage or even
that the glass has changed. Two elements of the lens are
made of Lanthanum glass. At least one of them also contains
some Thorium, so is radioactive. There are reports of glass
browning. It may also be a change in the cement used in the
lens.
  Aero Ektars were used for color photography for a time
after they became available surplus after WW-2 with
evidently acceptable results.
  Most aerial lenses are used with yellow or red filters for
haze cutting so its possible the blue correction is not as
good as it could be, but, again, it doesn't show up in the
analysis in Smith.
  Both the 7" and 12" version of this lens were intended for
aerial recconaisance work, mostly night photograpy using
flash bombs.
  They became available in great numbers on the surplus
market after WW-2 at rather low prices.
  I would also like to hear from anyone who has actually
used one especially as to the color correction and whether
anyone has observed browning.
  The evidence is that although somewhat radioactive they
are not dangerous.
  There are some articals on the web about the Aero Ektar,
I'm surprized a Google search didn't turn them up.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com