[LargeFormat] radioactive lenses

[Clive Warren]

At 11:05 am -0600 24/11/01, Michael Briggs wrote:
>Hello all,
>
>I have been researching the Aero-Ektars.   Soon, when I have time, I 
>will write
>up the results of my research.   Unfortunately much of the information on the
>internet is wrong including some of the information on the link given below.
>Regrettably too many people are guessing and their guesses are being 
>accepted as
>fact.  I have based my conclusions on patents and research articles from the
>1940's and on laboratory gamma-ray spectral measurements.   I am by profession
>a gamma-ray astrophysicists and so have training and experience in 
>radioactivity
>and laboratory measurements.
huge snip

Michael,

Thank you for setting the record straight about the Aero Ektars. 
After reading your comprehensive post have just placed the Aero Ektar 
in the corner of the room furthest away from my seat at this machine 
:-)

Perhaps you could explain briefly the nature of gamma radiation - all 
I know is that this is quite penetrative short wavelength radiation. 
 From what you say, this is emitted from the lenses but what about 
frequency?? If there are an exponential number of daughters and when 
the daughters decay gamma and xray radiation is emitted then surely 
this is not too healthy?  What sort of shielding is required to stop 
any gamma and xrays reaching me here at my seat - eyes large Aero 
Ektar with increasing respect ;-)

The more normal non-aero Ektars generally are probably my favourite 
old large format lenses and always seem to produce excellent results. 
I haven't yet tried the Aero Ektars but will be using the 7" when the 
skies eventually clear in this part of the world - heavy rain again 
over the weekend .........

Cheers,
        Clive