William, from what I understand this is the "old" type 100mm macro lens, which was introduced in 1991 I think. In 2000 the newer type with USM was introduced.


Anyway, it's quite hard to find a review for it. I did find two, maybe useful, links:


http://www.flickr.com/groups/canon100mm/discuss/72157594301865007/


http://www.thephotoforum.com/forum/photography-beginners-forum-photo-gallery/233138-canon-100mm-macro-usm-vs-non-usm.html


Perhaps it's of any help. From what I've read so far is that IQ wise they aren't that difficult, but who am I to say.


How do you like the lens? It's definitely not the EF100mm f2.8 macro USM, so if that's what you've paid for, you're scammed. I personally liked the internal focus a lot on my 100mm f2.8 macro USM.


Good luck,


Ja