Never thought about it until someone mentioned it on one of my photos, so now I am thinking about getting one. All my legacy glass is Canon that I have from my film days and I am unfamiliar with Nikon (have never used Nikon). When I got my Fuji X-E1 I wanted a 1:1 macro and ended up getting a Lester Dine in Nikon mount. The two teleconverters I have found are the TC-200 and TC-201, with the 201 being for AiS lenses. I really don't know the difference between Ai and AiS and not sure how that would relate to using it adapted to the E-M5. Anyone able to explain what the difference is between Ai and AiS as it relates to adapting the lenses to another system and if there is any difference in the optics between the 200 and 201. I would greatly appreciate it.