Working/writeup on a Jupiter-3, 1956

Discussion in 'Adapted Lenses' started by helinophoto, May 5, 2016.

  1. helinophoto

    helinophoto Leica Place Rookie

    Apr 12, 2016

    Just keeping y'all updated on my recent Jupiter-3 purchase.
    I am not a pro, but I really like to relax(?) and tinker with these old lenses when I am not working in IT. ^^
    I play around with them to use them myself, not for sale or anything like that.

    Brian's notes all over the internet has always been very helpful and answer just about everything you could possibly think to ask, well almost. ^^

    Anyway, bought a Jupiter-3 from eBay, directly from Ukraine. The seller assured me that the lens could be taken apart, everyone should really ask, I have also bought a Jupiter-3 which was glued. (unfortunately, that ended up in the garbage can, still glued, after trying everything, even two pipe wrenches lol ).

    Anyway, as for cleaning these buggers, some gunk is easier than others.

    IMG_4220 - Copy.JPG

    I used a long list of stuff to clean the grooves for the focus and lens mount to no avail.
    Vinegar + dishwasher + water solution (works great for your bathroom by the way)
    Ketchup(! does contain acid and can clean coins)
    5% Ammonia (good for removing grease, and also to create monobath-developer, remember hold your breath)
    White-spirit clone, supposed to be milder than the regular stuff.
    Lighter fuel
    Autosol Chrome Polish

    I actually ended using something we call "Ventilation grinding paste", IE stuff you normally use to make yourself a ground-glass.
    Tape and toothbrush and paste, times 3, with intermediate Autosol rubbing finally got rid of the main part of the gunk. Still not perfect, but much much better. (Autosol will clean the shiny parts but not the grooves, that stuff needs something that actually grinds it away).

    So, after outer cleaning and lubrication, time to test.

    Camera is Leica M6 with a cheapo adapter-ring which works just fine with other lenses.

    First I did a benchmark-test, no added shims (there was a 1.85mm shim inside this lens, it also had some distance from the stand-off ring to the base of the optical unit, probably corrected years ago to fit some FSU camera).

    I normally do my test-shots on fences usually, 1 (3ft) meter 5 (16 ft) meters and 10 meters (32 feet).
    On this sign, I focused on the white spec on the figure on the sign at 1 meters.

    Lens showed back-focus (increasingly the further away I got)



    I fiddled around at home and made 2 paper shims, total of 0.15mm extra shims.

    Strange result:

    1 meter seems fine, a little bit back-focus tendency still, but perfectly usable.

    However, on 5 meters the focus suddenly crept forward:


    Even more apparent at 10 meters:


    So that was strange.

    Is the lens short or long....? :)
    Wide open performance at 1.5 is actually very good, would have been awesome to understand what to do, to correct the lens ^_^

    I have grinded Jupter-8's before to adjust their focal length, but they were consistently long with the increase in front focus.
    I think I see the same here, now that I adjusted the focus with the added shims.

    However, I don't understand why the lens was consistently back-focusing with no added shims, but increasingly front focusing with 0.15mm added shims.

    Seeing I have added some shims already, and close focus has back-focus bias wile far away has front-focusing issues, adding more shims, would worsen the increasing front-focusing problem?

    Should I remove the extra shims (start over) and try and increase the focal length of the lens?
    Should I remove the extra shims (start over) and try to decrease the focal length until i get close focus ok?

    I suspect that the lens is on the longer side, but I may be wrong ^^
    Last edited: May 5, 2016
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  2. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    This is typical- increasing the shim corrects the back-focus when used close-in, but makes the lens front-focus at infinity.

    Stopping the lens down Increases DOF- but more importantly Decreases the Focal Length due to spherical aberration, and shifts the actual focus towards infinity.

    SO: I would try removing the Two shims and Decrease the focal length by moving the rear group in closer to the front group. You might need to remove the shims that were originally in the lens. You need to move the rear element by 0.5mm ~ 1.0mm to really see results across the whole range. Remember that moving the rear element closer to the front both decreases the focal length (slightly~) and increases the actual back-focus (the reason you need to remove shims).
  3. helinophoto

    helinophoto Leica Place Rookie

    Apr 12, 2016
    Thanks for answering :)

    Ok, good to know. I suspected it, but I really didn't want to start mucking about without some kind of confirmation :)

    I have the day off tomorrow, so then I can tinker, will report back when I got some results/conclusions :)
  4. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    Grinding down the barrel of the J-3: best to remove all the glass, leave aperture open all the way, stuff some paper into the rear- to keep the filings out of it. Then flood clean from the top in case any metal got into it.

    Good Luck! And- I have extra barrels if things go badly...
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  5. helinophoto

    helinophoto Leica Place Rookie

    Apr 12, 2016
    Thanks for the heads up (I see you have also mentioned that in one of you excellent tutorials) =)
  6. helinophoto

    helinophoto Leica Place Rookie

    Apr 12, 2016
    Hmm, looks like I just hit a brick wall. :(

    The rear triplet is glued shut, there is no way to budge it.

    I've placed the whole thing in an acetone bath, filled it up to the aperture blades. I don't have a spanner yet, so the whole optical module is in there. (need to see where I can get hold of spanners). Hopefully it will dissolve it after a week, or ten.
    If not, it's another dead end.
    - I do have a spare rear triplet, so I don't care if I ruin the one currently glued on.

    If it doesnt work out, I guess that's the end of the road for me and Jupiter-3's, already $400 in the hole two J3-purchases, both glued one way or the other.

    What is it with these Russians and their glue anyway? The tripet stays in place when it is screwed in, why glue it? :hmmm:


    I was able to remove the glass, luckily the nameplate and the deeper screw wasn't too tight, to i was able to poke them loose with a small screwdriver (not recommended!).

    Going to carefully clean the glass and wrap them in some cotton, awaiting the rear triplet (should it happen).

    Last edited: May 6, 2016
  7. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    Let me kn ow how it goes. I have lots of spare Jupiter-3 triplets and barrels, left over from conversions and repair. A 1956 ZOMZ (triplet)- that design was used from 1956 to ~1962, I have spares.

    SO_ don't give up, don't throw things away.
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  8. helinophoto

    helinophoto Leica Place Rookie

    Apr 12, 2016
    Thanks for the encouraging words, I'll keep the unit in the solution and report back in a week or two =)
  9. helinophoto

    helinophoto Leica Place Rookie

    Apr 12, 2016
    Ok, so here's the conclusion to this little story ^^

    I was never able to loosen the stuck rear-triplet from the original lens (not even after 2 months in acetone), stuck like it's welded in place :/

    Eventually, I got hold of a new lens-barrel with aperture blades. (no glass)
    I then proceeded to put the glass i had into that one and mount the rear triplet from my very first J3.
    - A real bastard-lens if you ever saw one (the glass and triplet are from 1955-1957)

    I have done some trials too, after adjusting (and filing) the lens.

    It should be pretty much spot on until 5 meters, and beyond that, it's creeping up from around 5 inches in-front of the subject at 10-15 meters, which isn't too bad, all things considered, stopping down a bit fixes that. :)

    Ektar 100 @ 50, Leica M6 with Jupiter-3 @ f2.8

    Portra 160 @ 100, Leica M6 with Jupiter-3 @ f2.0-f2.8

    Thanks for all the encouraging words and good advice :)
    Last edited: Jul 30, 2016
  10. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    It looks good to me! 5" of front-focus at 10m is less error than most J-3's, the Sonnar focus shift is towards infinity. I find ti best to use F2~F2.8 for distance shots on most of them. I've had two very early J-3's that required moving the rear triplet farther out, they were the exceptions. Neither had ever been used.

    Some Sonnars and J-3's seem to have "Hot mounted glass". Put the triplet into the fixture with the balsam still hot. Use the fixture to center the elements. They tend to stay in the fixture after this procedure.