The 1962 Focus Mount for the J-8 will focus somewhat closer than the other versions. Not all cameras take advantage of it, but the Zorki 3M and M8 do. That may be why the DOF different. It is an F2 lens!
squirrel$$$bandit
Veteran
I was quite surprised at how closely I could focus on those chickens. A nice bonus! And the lens is rather handsome on the M8 as well.