Magnus
I stand corrected, but inestimable page on cameraquest which I referenced says
'van Hasbroeck, however, states that it was recomputed in 1966 from # 2166702 onwards with noticeably improved performance.'
My problem was around '70 Victor Blackman, Fleet street photg, 1/2 page every week in AP, said the new design is absolutely flare free, - compared to the previous and I went out and bought one...
There may have been two changes I'll see if I have records, I was not expecting not to have filter threads.
To tell the truth I liked the high key dreamy shots I got/get, in extreme back light cases and the freedom of going to 1.4 in more normal (dark) lighting.
Given I like compact and light weight, I think it is a nice lens, if I dropped it I'd buy another, the cost and scratches from other users would be a pain. New aspheric too big...
Noel