Re: Kodak Aero-Ektar lens

----- Original Message -----
From: "Peter McDonald" <mcgordon@netspeed.com.au>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, November 30, 2003 3:45 PM
Subject: Kodak Aero-Ektar lens

> In the process of generally cleaning up my generally
dis-organised photographic gear in anticipation of having to
store a 20x24 copy camera I 'lucked' onto from a local
university, I unearthed another odd lens. It is a:
>
> Kodak Aero-Ektar f2.5 7in (178mm) 5x5 E E 113616, Made in
USA by Eastman Kodak Co., Rochester, N.Y.
>
> It has 6 stops: 2.5, 4.0, 5.6, 8.0, 11.0, 16.0
>
> The lenshood is probably purpose made as it has 6 locating
points, both inside and outside the hood.
>
> There is also a focusing tube which screws onto the back
of the lens, but does not move of itself . I assume this
focusing element mated into a corresponding point on another
part of the areo-camera.
>
> I would appreciate if someone on the list could advise if
it is worth talking to someone like Steve Grimes to
refurbish it and add a shutter. The glass is in very good
condition, other than needing a good clean.
>
> Ta muchly,
>
> Peter MCDonald
> Canberra, Australia.
>
  Steve Grimes died a while back but his shop is still in
business. http://www.skgrimes.com
  However, I am not sure its worth putting much money into
this lens. Aero Ektars were designed for photo recconaisance
using flash bombs. They were made in large quantities in 7"
focal length fpr 5" wide roll film, and in smaller
quantities in 12" FL for 9x9 aerial cameras (10" roll film).
Both are slightly radioactive from trace amounts of Thorium
in at least one of the elements. Aero Ektars are sharp but
do not have the very low geometical distortion found in
aerial mapping lenses. The EE prefix dates the lens from
1944.
  The focusing mount was undoubetly made for the lens.
Aerial cameras are fixed-focus at infinity so there is never
any focusing means. These lenses were usually used with
yellow or red filters, some of which have built in heaters.
The lens shade was also some aftermarket thing.
  The easiest way of using an Aero Ektar is to mount it on a
Speed Graphic and use the focal plane shutter. When used on
a Graphic its helpful to make a support block for the body
of the lens to make it more rigid, the lens is pretty heavy
for the front standard to support without help.
  Aero Ektars were very widely sold surplus after WW-2. They
were often used on Speed Graphics for 4x5 color photography
because of the slow color film available at that time (about
ISO-10) but fell out of use when faster color film became
available.
  There are some reports of poor color performance from Aero
Ektars. The prescription is probably that in USP 2,343,627
(Aklin/Kodak) a seven element Biotar type. The computer
analysis published in Smith, _Modern Lens Design_ show that
the lens does have a little longitudinal color though no
more than many other Biotar type lenses. Generally, its a
very well corrected lens.
  The radioactive element is probably the inside element of
the rear component. The activity is slight and not dangerous
unless you are going to sleep with the thing. There have
been some reports of browning of the rear element. I suspect
this may be the cement rather than the glass although long
exposure to ionizing radiation can cause some glasses to
become brown.

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