[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Rollei] WTB: Uncoated diffuse focus lens



- ----- Original Message ----- 
From: "Jose Menendez" <jgarciamenendez  >
To: <rollei  
Sent: Saturday, January 24, 2004 1:23 PM
Subject: Re: [Rollei] WTB: Uncoated diffuse focus lens


>
>  This topic made me search for a big old brass J.H.
Dallmeyer soft focus
> lens that I never tried yet: it seems to be a Petzval type
lens but has no
> much information on it; it has an iris diaphragm marked F
3 to 22 but no
> focal length, 3B  -  Patent 1866 & 1909 and an inscription
"TURN FOR SOFT
> FOCUS" with an arrow and another pointed arrow in a collar
that don´t
> seems to move, it has a maximum diameter of 11cm (4´1/4)
and a length of
> 17,5 cm (6´3/4).
> Can anybody give me more information? Should the collar
rotate to achieve
> softer focus?
> Thanks in advance
> Jose Ramon
>
>
  Kingslake, in the lens section of _Handbook of
Photography_ lists the f/3 Dallmeyer lens among soft focus
lenses of the Petzval type but doesn't show the
construction. This lens was made in focal lengths of 6" to
17" with a field coverage of 36degrees. An f/3, 17" lens
must be an impressive chunk of glass. I don't know for
certain but suspect the barrel should turn or slide to
change the spacing of one of the lenses. Its probably stuck.
  Dallmeyer made a famous portrait lens called the Dallmeyer
Bergheim lens at one time, an adjustable soft focus lens,
but this is not it, too fast.
  The patent dates are interesting. 1866 is the date of the
Rapid-Rectilinear patent. Why it should continue to be on a
lens made after 1909 (from the second patent date) is beyond
me, it would have expired long before. The lens is not
included in the list of Dallmeyer lenses in the above book
so it was probably not made after about the 1920's. While
this book was published in 1939 it lists many lenses, and
some manufactureres, who were long out of business by then.
  I wish I had more.

- ---
Richard Knoppow
Los Angeles, CA, USA
dickburk  

------------------------------