Hi pscion,
Edit to add: Sorry, i know this thread is two weks old, but I only just saw it and thought that it might be interesting enough to reply...
I can't give you in-depth info, but what I can remeber is that this lens was marketed in the late 70s/early 80s. I recall the various Soligor ads in American photo magazines, and basically it was touted to produce better results at both focal lengths and a more constant apeture for a lower price than a full zoom lens with widely varying apetures across it's range...
If I recall correctly, dual or even triple focal length options was actually a crucial necessisity in the cinematography industry. Zoom lenses simply did not exist back then in the early days of B&W silent movies, and it was probably only much later that zoom lenses of high enough quality could be made 'affordably'. The term 'affordable is relative. Interestingly, while movie cameras and probably obscure still cameras had dual or more lens boards since way back then, it was only in 2001 that a patent was issued for a camera with dual focal length lenses (
http://www.patentstorm.us/patents/6282377-claims.html).
Pentax also had a prototype dual focal length lens - the 32-39mm f/2.8 that, according to one historian, never made it to production, while Konica Japan launched their HEXAR RF?-HEXANON dual focal length LENS 21 - 35 / 3.4 -4 for their Hexar RF camera (or Leica M) sometime in 2002. The info is no longer in the Konica Minolta website, but you can see forumers discussing it here:
http://photo.net/bboard/q-and-a-fetch-msg?msg_id=002nsi
On the whole, whatever little I could remember of Soligor was what I would roughly classify as 'consumer grade' picture quality, and given the advances in lens manufacturing, I probably wouldn't pay more than SGD20-30 for a used copy of this lens in good working condition today. You might want to give it a try, just for the pure fun of having it, if nothing else. Mind you, I'm speaking from a film-based logic. Who knows, the Soligor may produce very nice results on a DSLR!
CHEERS!
