I know of 3 different variants of this (35mm f2 FD)lens, but would like to get the input of the resident Canon-ologists and FD gurus. What I would like to know is the following: -how many were there? (I know of the two locking ring, original FD era f2 and f2 SSC as well as the New FD version - is there more?). -what were the differences (I know some had the concave front element, for example). -which are more/less desireable (from a performance point of view) I just spend some time doing research on this lens - and found a lot conflicting reports (especially as to which lenses had the concave element, as well as the pros and cons of that). I would really appreciate it if any of you could clarify this for me or point me to a site that can help (I found the photography in Malaysia site to be a good stand by, but on this subject I found little info, and much contradiction). Thanks in advance for all and any help and information, Peter.