This is becoming much more complicated than need be. Yes, there are some very good non-Series 1 lenses designed by Vivitar. But, as I said before, the early Series 1 lenses, ROCK! And meet or exceed OEM lenses (as do many Kiron's). I don't have the time to go into the whole Vivitar history. PLEASE, just tell me what focal length you are looking for, and I'm more than happy to hook you up with a Vivitar Series 1 or Kiron lens that you will be very happy and satisfied with. And if you come across a non-Series 1 Vivitar that you are interested in, I'll gladly give you the history and the lineage of it. Many of the non-Series 1 lenses are very capable performers.