[LargeFormat] Aero-ektar question

[Richard Knoppow]

----- Original Message -----
From: "Joseph O'Neil" <joneil@multiboard.com>
To: <largeformat@f32.net>
Sent: Saturday, October 19, 2002 10:19 AM
Subject: [LargeFormat] Aero-ektar question


> Hi All;
> I picked up one of those classic 178mm, F2.5 Aero-ektars,
complete with red
> fitler, in good shape.  No shutter, but Iris, and
eveyrthign works
> otherwise.  Serial number EM3025 -so that is 1943 if iam
correct?
> Anyhow, i only shot B&W, and I have a spare lens board for
my 4x5
> mono-rail.  I am 99.9% certian this lens will cover 6x6,
having read
> serveral reports on the web of people using this lens for
that format,  and
> I am pretty sure about 4x5 as th elens itself says "5x5",
but before I do
> drill alensboard, does anyone know for sure?
> I did a search on  the net, found many references to this
lens, but
> nothing to state how much coverage it exactly had.
>
> Did read lots of neat stuff about "radioactive" glass, but
those
> radio-active lenses are supposed to have a brownish cast
in teh read lens,
> and settign thelens ona  light box, I see no cast.  That,
and my Civil
> Defense geiger counter I obught off ebay (don't ask -
impulse buy) fails to
> show any readings, but then, that geiger counter was
problaly made for when
> they dropped big nukes, not small time radiaiton.  :)
>
> thanks much
> joe
>
  They cover 4x5 fine. A correspondent of mine checked an
Aero-Ektar with a Geiger counter and found it was slightly
radioactive. The activity probably comes from a small amount
of thorium included in one or more of the elements. Thorium
is not an impurity, as sometimes stated, rather it was an
ingredient of some mainly Lanthanum glasses to modify their
properties. Glass with larger amounts of Thorium is quite
radioactive and has not been made for many years. It had
desirable values of index and dispersion. There is some
browing of glass due to radiation but the glass in the
Aero-Ektar is not sufficiently radioactive to develop the
staining.
  I've heard variable reports about the performance of these
lenses. Some report problems with chromatic aberration. The
published data indicate the chromatic should be well
corrected in the visible range, I don't know why some lenses
seem not to perform well.
  The design was something of a compromise but I no longer
remember what exactly was compromised. The info is in the
patent, I think.
  Aero Ektars were made for aerial reconnaisance especially
at night using flash bombs. They were not intended for
aerial mapping or other high precision applications.
  There was some vogue for them right after WW-2 for
location color photography mainly on Speed Graphics.
Somewhere I've seen a picture of Peter Gowland shooting
glamour stuff on the beach with such a rig.
  EM is 1943. The Aero-Ektar is a seven element Biotar type
lens. Kodak also built a 12" version of this thing for use
on 9x9 inch cameras. They are huge.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com