Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Started Apr 30, 2016 | Discussions
Slowdive101 New Member • Posts: 12
Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

I've posted this to the Sony forum, but it was suggested to me that I might have better luck here...

I've seen this discussed innumerable times, but some of the answers I've seen are contradictory. Hoping to get a definitive answer.

I'm trying to couple an M39-mount Jupiter 8 lens (serial # 7472208, if that makes a difference) with my Sony A7ii. So far I've tried two adapters: A Fotga M39-NEX and a no-name L39-NEX. Both adapters are not allowing me to focus to infinity.

Side note: I've got the exact same problem with an Industar 55mm f2.8 (serial # 9118910). It's an M39-mount, and using the two adapters above, I can not focus to infinity.

So what so I need to do to get these two badboys up and running?

Thank you!

Canon EOS M3
If you believe there are incorrect tags, please send us this post using our feedback form.
ProfHankD
ProfHankD Veteran Member • Posts: 6,241
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Slowdive101 wrote:

I've posted this to the Sony forum, but it was suggested to me that I might have better luck here...

I've seen this discussed innumerable times, but some of the answers I've seen are contradictory. Hoping to get a definitive answer.

I'm trying to couple an M39-mount Jupiter 8 lens (serial # 7472208, if that makes a difference) with my Sony A7ii. So far I've tried two adapters: A Fotga M39-NEX and a no-name L39-NEX. Both adapters are not allowing me to focus to infinity.

Side note: I've got the exact same problem with an Industar 55mm f2.8 (serial # 9118910). It's an M39-mount, and using the two adapters above, I can not focus to infinity.

So what so I need to do to get these two badboys up and running?

Thank you!

Either the adapter is accidentally wrong or the lens is... which seems unlikely in either case given two samples of each.  So, here's my guess....

There is a minor issue with M39: there are really three different things associated with the same thread name. One was used by Leica (sometimes called LTM or L39) and has 26 turns per inch for a 0.977mm pitch with 28.8mm flange distance. USSR FED cameras used true M39x1mm with about the same flange distance. USSR Zenit SLRs used M39 but with a longer flange distance of 45.2mm.  BTW, if your adapters are really marked correctly (which is far from certain), L39 is wrong for your USSR lenses.

So, the question is basically which M39 do you have?  If you can't focus anywhere but really close, you've got lenses with the short flange distance and a longer adapter. The reverse will get you maybe near infinity at the closest lens focus setting, past infinity otherwise. Really minor misses on the focus range could be from a LTM/M32 mismatch or from slight errors in adapter thickness or lens calibration.

 ProfHankD's gear list:ProfHankD's gear list
Canon PowerShot SX530 Olympus TG-860 Sony a7R II Canon EOS 5D Mark IV Sony a6500 +30 more
MOD Tom Caldwell Forum Pro • Posts: 35,673
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Another problem - supplementary information to ProfHank proper reasoning.

The Jupiter-8 is a Sonnar design and like all Sonnars (I think) will come apart by grasping each end of the lens and rotating them to allow it to screw apart.  It might be a little tight to start (it needs to be).  But it should not need excessive force.

Inside there will be a spacer ring - this is the rough infinity focus setting.  Different sized spacers were used to get the infinity approximately right.  The problem is that if the infinity is well out of whack then it will need a different thickness spacer ring.  They are hard to come by and hard to make in a small workshop.

If the infinity focus is only out by a small mount then the external screws on the focus ring can be loosened and the lens screwed to actual infinity - the distance scale adjusted to match infinity mark.  The problem could be that the lens stop has reached infinity on the scale before it has actually reached true infinity.

Be aware that the screws are tiny, that the lugs are easily broken off - care and a suitable sized screwdriver is necessary (even then it is a lottery).  A broken screw is almost impossible to replace.  You have been warned.

Another fix is to shave just a tiny amount off the adapter surface - best done on a metal lathe. But if the adapter was without fault then this makes the adpater and lens inter-dependent.

I used to think that most adapter manufacturers made their adapters within tolerences - and this is generally true - they tend to focus a little past infinity so as to cope with badly adjusted lenses (which is a slight annoyance when your lens is properly adjusted).

However I did (famously) buy 20x Fotga LTM to M4/3 adapters and every one of them was 0.9mm out of adjustment.  This seems a small amount but it rendered every one of my proposed per-adapter-dedicated LTM lenses into a problem.  It seems that most of my lenses Russian or otherwise must have been perfectly set for infinity when I bought them.

I then set about finding a well made adapter and tested six different types of these: the Fotga (cheapish) and the K&C Concepts (also 0.9mm error) (relatively expensive) were complete fails and the Fotosy was only out by 0.1mm which I took as being acceptable. The others were spot on accurate - including the cheapest one I could find.  Therefore adapter cost is not a guarantee of good manufacturing tolerances.  I have a thread on this adventure which can be found by a search.

No excuse but I think that the faulty adapters were probably mistakenly made for Leica M tolerances which are exactly 1.0mm different from LTM flange focus distances.  The remaining 0.1mm would have been the traditional past infinity focus slack for errant lenses.

-- hide signature --

Tom Caldwell

OP Slowdive101 New Member • Posts: 12
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Thank you for the response. It was suggested to me in another forum that I give a Novoflex adaptor (which is short by design) a try. Not being one who likes to tinker to much with gear, I may give this a shot.

MOD Tom Caldwell Forum Pro • Posts: 35,673
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Slowdive101 wrote:

Thank you for the response. It was suggested to me in another forum that I give a Novoflex adaptor (which is short by design) a try. Not being one who likes to tinker to much with gear, I may give this a shot.

I am afraid that things that are not right are a small feature of adapting old lenses. If you buy enough of them sooner or later you will turn into a lens mechanic of sorts ....

I bought 8 rubbish Helios 44 lenses in bulk at $15 each just to practice on.  I have three of them working well enough.  I might get a couple more working yet.  But it would simply be easier to pay "$60" and get one good one as they look ugly no matter if they are "sort of" fixed and working.  But pulling them down, cleaning and rebuilding them has improved my skills without spending the earth.

"Tinkering" can be very frustrating but a lens fixed becomes a precious thing that your learned skills have repaired.  But the warning is there that you might go stark raving mad in the process.  The Jupiter 8 is one of the easier lenses to work on and there are "how to's" kindly posted up on the web.

But try your new adapter first - it is much easier if it works.

Novoflex have a reputation of being very precise and very expensive. By process of elimination you will soon know if the lenses are at fault.

Also what ProfHank was saying is that there is a another adapter also with a M39 thead that was designed for the Zenit camera.  This used the same thread as the much shorter LTM mount (Leica Thread Mount for RF camera lenses).  The Zenit M39 was designed for slr camera bodies and had a longer flange focal distance for suitably designed bodies.  This was so that the lens would clear the internal mirror. This mount was a precursor to the more universal M42 mount which was adopted by Russian manufactire in due course to avoid confusion.

Direct LTM to NEX E/FE adapters have been quite rare until recently. Most LTM had to be first adapted LTM (thread) to LM (bayonet) mount and then further adapted to the camera body of choice.

I did try six brands LTM to M4/3 mount adapters myself and found two of them quite unacceptable - Fotga and K&C Concepts. Perhaps this problem carried over to the NEX version?  I think it was caused by a factory mistake which confused the flange focal length of LTM with LM which is 1mm different.  In lens mounts 1mm might as well be 1 metre.

-- hide signature --

Tom Caldwell

mapgraphs
mapgraphs Senior Member • Posts: 1,218
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem
1

Slowdive101 wrote:

Thank you for the response. It was suggested to me in another forum that I give a Novoflex adaptor (which is short by design) a try. Not being one who likes to tinker to much with gear, I may give this a shot.

As Tom notes, tinkering is a good part of adapting lenses from one mount to another mount. The tinkering can be hands-on or buying more parts. Or both ; - )

As for your immediate dilemma, if you can almost get infinity (get infinity by stopping the lens down for example) then the problem is either the adapter being too "thick" (sets the lens too far away from the sensor). Or it may be that the hard stop for infinity on the lens is incorrect, not allowing to lens to get to infinity focus. Or it could be both of these working together to prevent true infinity focus.

The M39/M42 register distance as Tom notes is specific to a particular mount. You would know this immediately because the lens would only have near focus. These lenses have an M39 thread but the camera register distance is that of a M42 lens. One can buy M39 to M42 thread adapters and then use a standard M42 adapter (for the most part, depending on whether the thread pitch is correct).

In any event, tinkering can be half the fun of figuring out how to make it all work, or not...  ; - )

OP Slowdive101 New Member • Posts: 12
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Thanks everyone. I'll update this thread if I get the lenses working. We shall see. The end lesson for me may be simply to stay away from M39.

Zonyman Junior Member • Posts: 42
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

It should be fairly easy to check if you adapter has the correct thickness.

Lens registration distances are 18mm for Sony E mount and 28.8mm for LTM. So, your adapter needs to be 10.8mm thick (that's the distance between the 2 lens mount flanges). Use calipers to measure the thickness of your adapter. The acceptable tolerance is around 0.1mm IMO (even this much will make the distance scale on the lens inaccurate). Anything more, and you need to modify the adapter (sand it down or add shims to bring it to the correct thickness), or, if you're unable to do so, just buy another one.

Some LTM adapters are adjustable (they have set screws which allow you to adjust the thickness). Other adapters have a "helicoid" feature (a variable extension ring). You might want to get one of these.

If your adapter has the correct thickness, and you still can't focus at infinity, then your lens(es) need to be adjusted / shimmed for proper infinity focus. However, I doubt that this is the case, since I purchased 3 different adapters to Sony E (1 from LTM, 2 from C/Y mount), all of which were off by various amounts between 0.2 to 0.6mm. I also have 4 russian lenses, including Jupiter 8 and Industar 61, all of which were properly calibrated for infinity focus.

 Zonyman's gear list:Zonyman's gear list
Sony a7 Sony a7R II Sony Vario-Tessar T* FE 16-35mm F4 ZA OSS Sony FE 70-300mm F4.5-5.6 G OSS +9 more
akincansenol
akincansenol New Member • Posts: 5
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

Slowdive101 wrote:

I've posted this to the Sony forum, but it was suggested to me that I might have better luck here...

I've seen this discussed innumerable times, but some of the answers I've seen are contradictory. Hoping to get a definitive answer.

I'm trying to couple an M39-mount Jupiter 8 lens (serial # 7472208, if that makes a difference) with my Sony A7ii. So far I've tried two adapters: A Fotga M39-NEX and a no-name L39-NEX. Both adapters are not allowing me to focus to infinity.

Side note: I've got the exact same problem with an Industar 55mm f2.8 (serial # 9118910). It's an M39-mount, and using the two adapters above, I can not focus to infinity.

So what so I need to do to get these two badboys up and running?

Thank you!

I had the same problem with M39 Jupiter 9 85mm lens, firstly I bought M39 to NEX adapter which was short L39 adapter and it didn't work. After I tried with M39 to an M42 step-up ring for attaching to my Fotga M42 to Nex adapter and it failed again (it didn't focus to infinity, just turned around 100mt).
After all, I tried with L39 to NEX adapter and 16mm extension tube mounted. It worked very well.

Hope you can achieve that

 akincansenol's gear list:akincansenol's gear list
Sony a7 II Sony a7 III Sony FE 28-70mm F3.5-5.6 OSS Sony FE 50mm F1.8 Sony FE 24-105mm F4 +15 more
tdwesbo
tdwesbo Senior Member • Posts: 1,928
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

I've seen some bizarre quality control/construction issues on the cheap ebay adapters.  Adapters with obvious flange distance issues, mounting pin holes the wrong size/place, label spelling errors...  I get the sense that some of these are just churned out by any old factory trying to fill out their manufacturing capacity and then private branded by whoever buys them in lots.  You live, you learn...

 tdwesbo's gear list:tdwesbo's gear list
Fujifilm X-T1 Fujifilm X-H1 Fujifilm XF 14mm F2.8 R Fujifilm XF 27mm F2.8 Fujifilm XF 35mm F2 R WR +3 more
doctor ed New Member • Posts: 15
Re: Jupiter 8 (M39 mount) with Sony A7ii Infinity Focus Problem

The problem is that if the infinity is well out of whack then it will need a different thickness spacer ring. They are hard to come by and hard to make in a small workshop.

a small circular spacer ring is literally the single simplest thing you could try to make.

but why go to that effort, it is literally just a simple spacer. a bit of plastic the right size will work. theyre just wedged into the assembly and are held tight as a hell once assembled.

if this is infact the issue, pulling the lens apart and experiment (taking it out altogether is a good place to start - does the problem now go in the other direction?) then try simply inserting whatever you have lying around thats kindve the right size to make it work. if you wantto get fancy later once youve sorted out dimensions, get a metal one made if you really really need to

Keyboard shortcuts:
FForum MMy threads