Lomography Jupiter 3+ not focusing correctly in the rangefinder patch

[MNS]

Greetings,

I've noticed a little issue with my Lomography Jupiter 3+ 50mm lens, where it's not focusing to infinity on my Leica's rangefinder patch or my Zorki 4K rangefinder either.



Both my Summicron 35mm ASPH and my KMZ Jupiter -8 50mm f/2 lens do align at infinity. I'm pretty certain the Leica or my Zorki are not at fault here. Whether the lens out of alignment I'm not sure, so I think it could do with a CLA to bring it back to spec.

Can anyone recommend a repairer in the United Kingdom that will service one of these lenses or Russian made cameras?

 

[Coldkennels]

Rangefinder lens servicing in the UK is rare and expensive; off the top of my head, the only places I could think to recommend are Skyllaney up in Scotland and Cameraworks UK, and I think Skyllaney has stopped working on general lens repairs (preferring lens modification instead) and Camerworks has a huge waiting list. If you've not had it long, it might be better to send it back to the seller.

If you're stuck with it (or don't want to send it back), a couple of thoughts:

• Leicas and Zorkis have slightly different rangefinder specifications to the point there can be compatibility issues between them. I assume that the Jupiter 3+ is built to "true" LTM spec instead of the Zorki one, so I'd focus on getting it working on the Leica.
• What does the cam look like on the back of the lens? I assume it's one solid flat ring like the original Jupiter 3, and not sloped or "shielded" like the 35mm Summaron? Both of those could cause issues if the lens isn't quite orientated properly on the body (which happens a lot with cheap LTM adapters on M mount cameras or LTM lenses used on Soviet cameras).
• Is it moving past infinity or falling short? Moving past infinity is less of a problem than the alternative for a few reasons.
• Does the focusing scale match the rangefinder patch - i.e. if the rangefinder has gone past infinity, is the focusing scale also slightly past the infinity mark?
• Does the lens actually result in correctly-focused images when using the rangefinder on the Leica?

 

[MNS]

What does the cam look like on the back of the lens? I assume it's one solid flat ring like the original Jupiter 3, and not sloped or "shielded" like the 35mm Summaron?

I've learned something new today and I think we can call this problem solved. 🙂

Reading through your post @Coldkennels, I suddenly remembered I had a new unused 50-75 adapter ring, originally purchased from Red Dot Cameras in London. I have been using the Lomography 50-75 adapter ring and come to think of it, I'd only noticed the rangefinder patch issue a few days ago after using the Jupiter-8 lens.



Left picture is the Jupiter 3+ on the Lomography adapter and on the right is the Red Dot adapter. Other than the name I can't much difference between them or so it would seem.



However, on the first image of the Leica with the Jupiter 3+ which the rangefinder patch doesn't meet at infinity and falls short. Note the infinity scale mark, near dead centre. The second image with the Red Dot Cameras 50-75 adapter, note the infinity scale mark isn't at the top. But! going outside I found the rangefinder patch near enough meets with this adapter. There must a difference in the thread length on each adapter!

I'm going to have to use the Red dot adapter for the Jupiter 3+ lens and the Lomography adapter for the Jupiter 8 lens.

Hey ho, many thanks Coldkennels.

 

[JeffS7444]

I was under the impression that the modern Jupiter 3+ was built to Leica flange-focal plane standard, not to the old USSR standard.

 

[rfaspen]

Yes. But it is an LTM lens and may suffer the age old issues with LTM-to-M adapters. Here, I think we're led to believe the Lomo adapter is too thick/thin or something.

 

[Coldkennels]

I was under the impression that the modern Jupiter 3+ was built to Leica flange-focal plane standard, not to the old USSR standard.

It's not a flange focal distance difference - they both use the same one (28.8mm, if memory serves - don't quote me on that without checking!). The issue is the "standard" focal length the rangefinder expects. Leicas, Canons, Leotaxes, Niccas, etc. all use 51.6mm as the nominal 50mm standard. FEDs and Zorkis use the Contax and Kiev's 52.4mm standard. What this means is that while the lenses are in focus at infinity, using a FED/Zorki lens on a Leica or a Leica lens on a FED will lead to more and more focus inaccuracy as the lens travels to the close focus stop. They move at slightly different rates and don't communicate that to the body the same way.

Here, I think we're led to believe the Lomo adapter is too thick/thin or something.

It could be that, but it could just be rotational accuracy issues. If you look at the photos @MNS posted, the Lomography adapter repeats the issue/mistake that a lot of modern adapters do - it tries to orientate the lens on a Leica so that the focus mark is at 12 o'clock. Proper adapters will usually have an LTM lens orientated with the focus mark off to one side; supposedly, this was so that it was easier to see around an external viewfinder. However, people then complain that the lens is "crooked" because they don't know it's supposed to be that way!

For some lenses, reorientating the lens so the focus mark is at the top doesn't matter. But on a lens with a "partial" focusing cam, one with a slope (to adjust for focus shift), or ones with a "shroud" or cut-out, having the lens slightly out of position can result in major focusing issues.



Of these three lenses, only the Canon 50/1.8 in the top left will work on an adapter that forces infinity into the 12 o'clock position. The Canon 135/3.5 at the bottom will mis-focus, and the 35/3.5 Summaron on the top right will completely disconnect from the rangefinder at a certain point because the follower can't stay in contact with the cam.