Originally posted by Mistral75 s 5962904, lower than the one of this mystery lens, which could therefore be one of the last smc Pentax-A★ 600mm f/5.6 ED [IF] ever manufactured.
Originally posted by vonBaloney This black one has a serial# of 5964967. My white one is #5712229, so it wouldn't appear that the black one was earlier than others.
Pentax did not always follow the rules when doing s/n's for some lenses. They did batches of lenses in s/n sequence, but not always lower s/n oldest to higher s/n newest over the entire production run of a lens. The A*600/5,6 is probably correct, but some older K series lenses were out of sequence.The first version of some K series lenses (1975-77) with the upper case name had higher s/n's than the second version (1977 to ~) lower case name lenses. Pentax also skipped big chunks of numbers in some lenses, like the first batch being s/n 5xxxxxx and later ones 7xxxxxx.
Example I have a K18/3.5 second version (1977 to 1985) that has a lower s/n than lenses from the first version (1975-1977)
Phil.