Hi everybody,
I tried to find (with Bayes nets) some correlation between the SN and the probability of having a good copy of the DA*16-50, and the only valid explanation seem to be linked to the fourth digit.
Based on all the samples, there 65% random chance to get a good copy. But if the fourth digit is 0, 1 or 2 then the probability increases to 89%. The digit to check is the X as in 902X306. (of the 147 SN I checked, 37 have X <=2). I cannot find any correlation with the other digits.
I am not sure how statistically valid it is but I guess that if I had to buy this lens I would give it a try! Who knows why... perhaps this correspond to a plant, or workgroup, or an individual... or it is pure coincidence.
Cheers,
Grégoire