Leica Tales from the Greasy Side: Miscellaneous Notes on the Jupiter-3

For Jupiter-3: ever notice a slight play in the focus, where it moves some small fraction of a millimeter before the dampening kicks in? OR -worse- it jams up after a CLA?

I learned to keep the guide screws in order, put them back in the same slot that they came out of. 90% of the time, will not make a difference. 10% of the time is where I spent 90% of the time figuring this out. These are the screws that hold the two main helicals together. When a lens has a lot of play, I will use a larger guide screw when re-assembling. The guide screw is "about the same" as that used for the aperture linkage. I built up spare parts by doing Sonnar conversions for people, keeping the old J-3 modules as part of the deal. Got a couple of good J-3's, and a lot of spare parts that way.

I use 1 scribe for the first rail and 2 scribes for the second. For the screws for the focus ring: I also keep in order, start with the hole counterclockwise from infinity mark. I've seen different sized screws used in the focus ring before. Will drive you nuts when re-assembling.
Make Scribe Marks to re-assemble.
by fiftyonepointsix, on Flickr

Keep screws in order, put back where they came from
by fiftyonepointsix, on Flickr

Focus Stop Screw: Always set to Infinity to re-assemble.
by fiftyonepointsix, on Flickr
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I'd probably get grease and detritus all over the optics ...

For those just starting this, I'd think setting up a tripod, then record the disassembly with sharp detail. Would likely come in handy for "Where did this go?" or "Did this thing or this other go in first?" or "Was this flipped this way or that way?"

Have you heard of any DIY techniques for polishing scratches out of optics or refurbing a coating or such?


Thanks for the tip, it's little things like this that can save a whole bunch of time indeed.

I've wondered a little about those kinds of screws when I have done my lenses, but always thought that "repeated use will smoothen things out if there is a problem", but good to be aware that there can indeed be a difference, even though things look more or less the same ( I know I tend to mix the screws, if there are two very similar ones, coming from the same section of the lens).
I've done instructions in PDF format, feel free to use, redistribute, and provide to a favorite Tech of you want.

This thread is for all the little stuff that not in the general instructions.

LIKE- this one! A postwar German Zeiss Sonnar, probably made as the factory was in disarray.

by fiftyonepointsix, on Flickr

The Middle Triplet cannot come out of the Barrel. I believe that the triplet was mounted into the barrel while the balsam was still hot, and the barrel did the aligning of the elements! "I've done that" when repairing separated elements. This one had tell-tale signs of the balsam flowing to the edges of the triplet. I cleaned the back surface by coming through the back, was not able to remove it.
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Real Name
Excellent topic!

I have two questions regarding grease:

1. Is there an explanation at hand why most old lens helicoid lubricants (edit: that I’ve seen so far, not so many I admit) today have the colour and consistency of earwax?

2. Since I live in a not so hot climate, can I consider to use «Vaseline» (pharmaceutical quality) as a replacement for the old helicoid lubricants, or is that a principially bad idea?
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Not sure about the chemistry behind old lubes, but the drying out is nothing that is specifically for old Soviet lenses, I've seen the same on old Leica-lenses as well.
I suppose every lubricant dries out after a while, no matter what, but modern lithium and silicone-based may last longer(?).

I would not use Vaseline for two reasons:
- It's viscosity is too thick, so your focusing may be very stiff to move. It will probably just end up getting thicker and thicker as time passes on.
- I don't think it's a lube that is specifically designed for that kind of use in mind, so it may migrate to other parts of the lens with temperature-changes and may get very thick in low temperatures, it's longevity may be questionable.

I would use a Lithium-based lubricant. The ones I have used on my Jupiters and my Leica Summicron f2 seems to work very well, apart from at winter-temperatures around -4 and lower, then it seem to harden up a bit.
Do NOT use Vaseline!

I use white-lithium grease, as mentioned above "most of the time".

I also use Vacuum Pump Grease for helicals that are loose, and under the aperture ring of the Sonnars and Jupiters. This gives a nice dampened movement and does not outgas/separate.

by fiftyonepointsix, on Flickr

A little dab will do it!
Another undocumented tidbit: The rear triplet and fixture are interchangeable between the KMZ Jupiter-3 and the pre-war and wartime Carl Zeiss Jena 5cm F1.5 Sonnars.

The shape of the glass and design of the barrel for the ZOMZ J-3 was changed, and will not correctly screw into the KMZ and Zeiss lenses.

I've interchanged front elements and middle triplets between KMZ and later J-3's, and have used the inner retaining ring for the middle triplet to repair a pre-war Sonnar.

Test shots with the 1936 CZJ Sonnar 5cm F1.5 with a 1955 KMZ Coated Triplet and Fixture.

Wide-Open, on the M9 using an Amedeo Contax-Leica adapter.

Sonnar Test, Wide-Open
by fiftyonepointsix, on Flickr

Test, Wide-Open
by fiftyonepointsix, on Flickr

Sonnar Test, F1.5
by fiftyonepointsix, on Flickr
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Hit a first on a Jupiter-3, a late Black Valdai sold by Fedka to a photographer in Australia, sent to me for shimming...

Lens had a very slight back-focus, and some play in the focus. Added a 0.04mm shim to correct the back-focus. Gave the option for a complete teardown, asked to proceed... Thought the problem would be the guide screws in the rails that hold the two halves of the helical were too thin. Surprise after opening the lens up, it only had one guide screw. I put a thicker screw on the one side, and put the thin one on the unpopulated side.

Illustration of the guide rails and guide screw:

Mark Both Slots, I use single and double marks.
by fiftyonepointsix, on Flickr

Thought I was done, the focus jammed half-way through the range. Turns out the rails were not cut straight. Shaving a little bit at a time off the sides, trial and error to get the focus tight and the wobble out- At the end, very nice focus through the range, and the wobble was gone. So was the need for the 0.04mm shim. Apparently, the back-focus observed was due to the wobble in the helical. I've taken apart a lot (>200) J-3's, this was a first.

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