Although I haven't used it professionally for years, my college degree
was in Civil Engineering, with a major in photogrammetry.  I try to
stay somewhat connected to the subject.

You might be interested in checking out Eos Systems' product,
Photomodeler Pro.  You can use images from non-metric cameras as input
to your project, and their software can compensate for lens distortion
by deriving the compensation information from photographs.  No need to
use a pre-calibrated lens.

I was thinking that a serious rebuilder could acquire, from overlapping
photographs, accurate dimensions of an instrument or its parts without
having to measure them in detail.  This might be especially valuable to
be use to recreate some measurement that you forgot to make!

Check out their web site: http://photomodeler.com/

Steve McCollum

 [ Freeware "PhotoModeler Lite 3.1a" (4.4MB) may be downloaded at
 [ http://www.photomodeler.com/Lite/  -- Robbie