Lens options
 

Is there any method to adapt S16mm lenses to the EX3? And if there is, what would the magnification factor be? So far there seems to be slim pickings in the 1/2" native format.

Seems likely, as there is a fair bit of back focus distance to work with on the EX3.
Magnification is always a factor of the focal length, so a 50mm lens made for a 35mm stills camera will give x5 or so magnification on EX3, and a 50mm lens made for a 16mm camera will also give x5.
So you are always going to have a problem at the wide end, as in S16 lenses you've basically got a Canon 8-64/7-63or Zeiss/Optar 8mm and that's about it, not that wide on EX3.
Drop Les a line at les@lesbosher.co.uk, he's a font of knowledge on these matters!
Steve