From: into@oblivion.nothing.com   
      
   "anorton"  wrote in   
   news:quudnYU2EoLXdr3SnZ2dnUVZ_tKdnZ2d@earthlink.com:   
      
   > I did mean the ridges on the front, not the inside. From the  photos it   
   > looks like everything that was painted black is one part and the outer   
   > brass tube and threads are another.  I have seen a few lenses assembled   
   > similarly.   
      
   I'm more inclined to think those ridges are for handling. The entire   
   outside of the body is threaded for insertion into the camera, and I   
   suspect focus is achieved by this threading. The lens came with a ring   
   on the body which appears to be used to lock the lens into position.   
   Also, these particular ridges are on both ends.   
      
   I haven't really researched the lens much. I've found very little   
   mention of this specific model no, but similar lenses are described   
   as used in large format film cameras. It's an f/12.5 4-1/4" Wollensak.   
   Besides using it as a loupe, I've also used it as a makeshift laser   
   optic, and experimented with it as a telephoto lens on a CCD. Very   
   sharp images. I don't recall where I got it, but I think I may have   
   picked up it in a surplus store with some other optics tidbits.   
      
   Brian   
   --   
   http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism   
   Sed quis custodiet ipsos Custodes?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)