Summitar collapsible barrel issue
I have a couple of copies of collapsible summitars from the fifties (hexagonal iris). Both have stiff apertures which I think i am comfortable with cleaning and regreasing, but one copy, when the lens is collapsed, the barrel rotates freely (it locks fine when extended), on the other the barrel locks into place when collapsed and doesn't rotate. I'm assuming they should both lock?
Also on examining the rear assemblies, the inner threaded ring with 2 notches on one is flush to the back of the lens, but on the other copy (the one that rotates freely) it is screwed in further. Which is correct?
Otherwise they are both in good shape and i'd really like to get them up to snuff.
Many thanks for any assistance.