if you think it is useless, you already know it, that is just fine with me - i am not here to proof anything
I for myself use it on a APSC Nex with infinity for a lot of lenses and i know it is modified in a newer version for FF Alpha and others
As all E mounts have the same 18mm register, it should reach infinity as well on your camera
Old russian M39 lenses ( not the reflex ones with M39 but Pentax register) come often with 0,2mm more register than Leica L 39, so you might get problems to reach infinity with a L or M 39 adapter, but this has nothing to do with VNEX