[LargeFormat] Aero-ektar question

[Les Newcomer]

On Saturday, October 19, 2002, at 12:50 PM, Richard Knoppow wrote:

>
> ----- 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
>
>
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