Congrats Andy with your J3! Sweet looking camera you´ve got there!Now go out and shoot some more, those Jupiters really feel fine in the dark winter nights with 1600 asa film
🙂
Sadly I´ve not been so lucky with the J3´s as my two lenses (1951 and 1981) are somewhat badly decentered
🙁 ....
As for shimming the lenses:
First the optical elements need to be screwed out of the focus mount (just unscrew with your hands...grab the lens on the focus mount and in front of the app. ring and turn anti-clockwise) then you see the metal shim wich is ether to thick (sanding down is in order) or too thin (i cut paper shims and sandwich them on the metall ring...works for me)
You need a ground glas on the tripod mount camera body and a good contrasty focus target (I use a needle pinned into a lamp-shade..lamp turned on) ..also use a lens (the shorter the focal lengh the better) as magnifier on the ground glas.
First I take out the metal ring and screw the optical element back in 1 turn then align the cameras rangefinder with the forus target at 1,5m (by turning the lens´s focus unit as if you would be focusing) and afterwards screw in the optical element for perfect focus (ground glas) on the target. (note the full turns you screw it into the focus mount) ..If you reach perfect focus you can mark the position of the aparture engravings on the focus mount and unscrew the optical element (again...note how many turns you screw it out)
After all that you can add shims or sand down the original shim so the optical element screws as much into the lens mount as noted and the markings of aperture align with your mark on the focus mount. ...finito!
this worked very well with my two Jupiter-3 and my J8 lenses and works on all distances. pity is that the aperture markings can be all over the place (and so not bee seen anymore)
For better explanations in far better english you can contact Brian Sweeny! he is probably the most experienced person with those Jupiters.
Anyone an Idea how to center the lens elements?!? can this be done?!?
here´s some of my faves with J3: