How to shim jupiter 3 to leica standard?

K

kevinbb

Newbie
Local time
9:00 PM
Joined
Jan 26, 2007
Messages
8
View My Gallery
After a lot of reading from the forum I ,finally, decided to get the first f1.5 standard lens for my leica IIIc and canon 7 - a jupiter 3 from GOMZ with sn. 67XXXXXX from evil*** bay.

Acording to the hypothesis of D. Stella, the jupiter 8 and 3s are designed for Zeiss ikon (and KIEVs) thus the ltm versions have to be shimmed for more accurate focusing.

Would Brian and other RFF members remember the link for the discussion on that issue? Or kindly tell me how to do that myself. My lens is coming from a russian dealer. I know it is 'risky' but the price (less than US$ 80 ) is quite attractive. 😱

P.S. Thanks to Brian's recommendation. A 1952 built LTM jupiter 3 was sold for 250 bucks on evil*** bay recently.😱

Another question is that can I sway a 85 optical module from a black jupiter 3 to the lense barrel of this 67 one?
 
Brian put up instructions @ZIF: "Adjusting the 5cm f1.5 J-3" RE: swapping an 85 optical module into a 67 mount - I recall that there were changes to the construction at some point. Maybe you send Brian a PM unless he jumps into this thread first.
 
Jupiter 8

Jupiter 8

Hi, i did it a few weeks ago.

First disassemble optical parts out from the body.

Then, unscrew both, front element and back one.

Here it´s the butcher´s job.
The problem is the separation tween those elements, in leica standard the distance is almost 0.7 mm less.

I got rid of the thread in which it´s screwed the back element. So both elements got closer.
Thanks to the rd1 i could test the results immediately.

It´s not that difficult and it really worked in my case. I found the jupiter to be an excellent lens. Before the surgery, it focused 8 cm behind the rf matching point.

Check the attachment.

Bye
 

Attachments

  • _EPS3159.jpg
    _EPS3159.jpg
    23.4 KB · Views: 2
Thanks a lot RFF members. These are the information that I am looking for. Can't wait to receive it from St. Petersburg.

P.S. Hi, elmer3.5 CAn you tell me a bit more how you remove the threads. By using some sort of drill, I supposed.

Thank you all.
 
Last edited:
Kim Coxon turned my shimming thread into a PDF and hosts it here:

http://pentax-manuals.com/repairs/j3service.pdf

I also out up a second set of instructions on the ziforums.com site:

http://ziforums.com/showthread.php?t=97

which shows what to do if the distance scale vs RF coupling is off.

I can't believe the '52 J-3 went up so high. My '53 J-3 was $93, shipped.

I would not change the element spacing unless shimming the lens does not work. I've changed spacing on two lenses, and shimmed dozens.
 
Last edited:
kevinbb said:
After a lot of reading from the forum I ,finally, decided to get the first f1.5 standard lens for my leica IIIc and canon 7 - a jupiter 3 from GOMZ with sn. 67XXXXXX from evil*** bay.

Acording to the hypothesis of D. Stella, the jupiter 8 and 3s are designed for Zeiss ikon (and KIEVs) thus the ltm versions have to be shimmed for more accurate focusing.


Another question is that can I sway a 85 optical module from a black jupiter 3 to the lense barrel of this 67 one?
Click to expand...


I have two J-3 which never needed to be shimmed for Leica. I've used them as standard lenses for the M3 and several IIIf's and IIIc's. The focus was never off. I've observed other J-3 too (owned by other friends who use it on Canon and Leica) which were never adjusted for Leica or Canon cameras.

Before you start reworking on your J-3, try it first on your Leica. If it focuses right as it is, then further adjustments will be unnecessary.

Some Jupiter-3 may indeed need some adjustments. And the same could be said of other Soviet lenses as well like the J-9.

I don't quite agree Mr Stella's theory on the J-3, on the basis of some observations. First, it assumed that the Soviets simply stuck the 'copied' Sonnar on LTM focusing barrels which had Contax focusing pitches. The original Contax Sonnar 1.5 did not have a focusing barrel- it was simply an optic component which sat on a focusing helical fixed on the camera body.

When the Soviets made LTM versions of the Jupiter for FED or Zorki (and maybe thinking of the Leica in the process), they had to create a focusing barrel for the Jupiter Sonnar. The focusing barrel they would have made would have been recalculated for the true focal length of the Sonnar clones- just as they would when they had to design barrels for lenses of other focal lengths. Mr Stella's theory assumes that the Soviets never did any of these recalculations. The Soviets were already in the business of making Leica copies before they started making Contax and Sonnar clones. They must have some idea of how to make proper LTM lenses.

One J-3 that I did find which focused erroneously was due to improper reassembly. It was missing its shims.
 
The Data Sheet that came with my LTM J-3 indicates that the focal length is 52.5mm, which is the Contax standard and not the Leica standard.

I posted a copy of the Datasheet once, and it created "an uproar" so I deleted the thread.

The FSU lenses are built to the Contax standard. Many have been adjusted over the years, many have not. I've found that 4 of 5 need some sort of adjystment, and have done 50 or so. Of those, only two required the rear optics to be moved in before shimming.

picture.php


Moving the rear optic in reduces the focal length. The difference in the throw of focus between a Contax and Leica lens is 0.1mm, from 3ft to infinity. USUALLY: shimming the lens for close-up and wide-open works well, and stopping down slightly for infinity works. The focus shift of the Sonnar works to your advantage. When the Focal Length is on the high-side of the tolerances, moving the rear module in will take care of the problem.

The focus mount of the J-3 does not correct for the difference between the Leica and Contax focal lengths: the optics module screws into the piece of the mount with the RF cam. There is no double helical for correction, and the RF Cam does not rotate. A cam that rotaes as you focus can have an arch cut in it to correct slight deviations in focal length. My Type 2 Rigid Summicron does this: has a slight cut in the RF cam. The J-3 does not do this.

Here are results from a collection of J-3's, most required adjustment. And it was not because all of them were misassembled on a kitchen table. Some of these were new, old stock. Others had never been opened, judging by the set screws having one set of taps.

http://ziforums.com/album.php?albumid=97

Everyone can have their opinions and theories. I prefer reading the Datasheet and taking things apart to find out how they work.
 
Last edited:
Thread removal

Thread removal

kevinbb said:
Thanks a lot RFF members. These are the information that I am looking for. Can't wait to receive it from St. Petersburg.

P.S. Hi, elmer3.5 CAn you tell me a bit more how you remove the threads. By using some sort of drill, I supposed.

Thank you all.
Click to expand...


Hi Kevin,

I removed it with sandpaper on a flat surface, it`s aluminium and wont resist that much.
Use circular short movements and mark clearly the edges that must be removed. Your hand will waste material unevenly. So be prepared to forsee this.
Cover the blades (set f22) with a piece of cloth to prevent aluminium dust reaching them and front glasses.
After you have done this, you`ll have to regulate the focus, not much maths for this. Since you have to screw the elements, figure it`s like focusing, with this principle try many distances and make a shot for each one.
To make this regulation process easier i put a cloth thread in the back element thread to add some resistance and to make the screwing stable.
Guess it`s the boring part of it (with a digital rf it`s quick!)

Bye
 
Brian Sweeney said:
The Data Sheet that came with my LTM J-3 indicates that the focal length is 52.5mm, which is the Contax standard and not the Leica standard.

[...].
Click to expand...


Hi Brian,

Given that the Jupiter-3 uses the Sonnar/Contax 52,5mm FL, do the existing theories account/discount the possibility/fact that the Soviets may have modified the focusing pitch of the lens focusing helical?

I understand the complications which will arise from using a Contax focal length with a Leica focusing barrel- the millimetre difference will sooner or later cause the optic to lose its synch with the rf coupling cam as the focus moves from minimum to maximum.

But, the popular theory suggests that the Soviets did just that- put a 52,5mm lens on a focusing barrel designed for a slightly shorter one. Would it not be possible to assume that the Soviets made an LTM focusing helicoid that was pitched to work right with 52,5mm? If it's possible for them to make helicoids which will synch the lens's focusing to the rf cam for other focal lengths (like 85 or 135, or even 35 or 28), how much more difficult is it to design one for 52.5?

They made similar helicoids for LTM for 85 and 135 lenses originally meant for Contax. The Soviets had to re-engineer the barrel helicoids for these lenses.

There is also one piece of information on the data sheet: the lens back register("Рабочее растоянние"= "Working Distance") of 28,8mm. That is a reference to a Leica specification. Camera instruction booklets, at least for the first models FED and Zorki and maybe the later ones, always recommended that the camera (lens working distance/back register) be sent for recalibration or adjustment when a fast Jupiter objective replaces the original lens.

I haven't seen as many J-3 as you have, perhaps no more than 10. But all of those worked right as they came. In fact, some of them which we initially thought to have focusing problems (when used on a Zorki or FED) turned out to be fine and good when used on a Leica.
 
The focus pitch of the lens helicoid will have it focus correctly at all distances on a camera with the RF calibrated for the Contax standard. The problem is the translation of the lens from 3ft to infinity is 0.1mm longer than what a Leica standard camera is calibrated for. The RF of the Leica will not agree with the lens for actual focus and will not agree with the distance scale. The optics move on a 1:1 basis with the RF Cam. On a lens such as the newer J-8 where the RF cam rotates as you focus, it would be possible to cut an arch in it to correct the difference. But- the J-8 was not built that way. It is also 1:1 with the optics.

My "trick" is to shim the lens so that the actual focus and the Leica RF agree at some close distance, wide-open. I use a TTL viewer and a Canon IIF: use the camera's RF to focus, note the distance on the lens scale, and hold the focus ring in place then shim the lens until the TTL viewer shows sharp focus. There is a sweet-spot where the two will be in perfect agreement, and then errors creep in as you move off that spot. The DOF at F1.5 covers most of the error. At infinity, closing down the lens increases the DOF and shifts the Sonnar focus rearward.

On adjustments: I'm using a high-magnification finder that goes beyond DOF. I've been able to see differences in focus changing the shim by as little as 0.02mm. Most often, i end up adding about a 0.1mm shim to the lens, which seems more than coincidence.


Recently, I was traded a 1969 J-3 that had been used on an M8, and was told focus was good. I ended up adding a 0.09mm shim to it for "spot-on". The focus did improve.

http://camwk.com/album.php?albumid=4
 
Last edited:
Brian I have read many posts on this subject by you.

I prefer to do my modifications/work on old LF cameras myself.

So, are you making these adjustments for others (for a price?🙂) I would love to send one to you for calibration.
 
My j3 finally arrived yesterday from st. Petersburg.

I flashed a headlight into the rear of the lens and examined carefully. No deep cleaning marks on the front and rear elements.

But a obvious sign of haze was observed on the surfaces between the first and second lens elements. This haze become less visible unless looking through the lens at bright objects. So, I suspect it will cause some loss in contrast.

Besides, I checked the focusing issues / problems by mounting the lens on my canon 7. Setting the shutter speed to 'T' and focus at TV (6 feet in front of my eyes) and a TV tower (at least a mile away ) In both cases, the images I got on the nikon K screen resting on the rails of my canon 7 were sharp. So, I think the lens is properly shimmed by somebody.

My question:

Should I take the risk of unscrewing the front element so as to clean up the mesh? If so, how to open the lens?



Thanks
 
Last edited:
kevinbb said:
Should I take the risk of unscrewing the front element so as to clean up the mesh? If so, how to open the lens?



Thanks
Click to expand...


Test it first. If the 'haze' makes your shots fuzzy, then some cleaning may be warranted. But if not, leave it be. There is a possibility that the adjustments may be lost or altered if you take the lens apart.

Cleaning marks can be a good indicator that the lens really worked- someone wiping it to get a 'clean' shot means that the lens was actually used on a camera. Both of my J-3 have light cleaning marks on them. They work just fine.

Both photos below were shot with a 1953 J-3, on a recently restored Canon II-S. This Canon is definitely up to Leica standard. Both J-3 have never been adjusted since I got them.

373188474.jpg


373188478.jpg

The film used was Fuji ciné negative F-400 type 8582, with an 85 filter to adapt it to daylight. Home-processed in modified C-41.
 
Last edited:
You need a spanner to take off the front ring. No set screws holding the name ring on as there is on the Wartime Sonnar. You need to take some care to take the ring off, and to get the front optic back on.

Unless the images are bad, it is not worth the risk of damaging the lens or misaligning the front element when putting back on. If you have to do the procedure, as you put the front element back on tighten the ring some, and tap the element a bit to help center it. I put it in an ultrasouns cleaner (no liguid) to help vibrate back to center.

Just to add- I have a 2nd 1953 J-3 coming to me from Russia, and just received a 1949 ZK Sonnar. The previous owner of the ZK did adjust the focus for his M5. Edit- just checked the focus, and it back-focusses even with the extra shim added. Needs another 0.15mm. I have a decent supply of J-3/Sonnar shims. The back module of the ZK Sonnar has a 6-digit stamped SN showing its German origin. I suspect it used to have a German nameplate, that was replaced when it was assembled. The 1958 J-9 in LTM that accompanied the ZK looks spot-on for focus. It's gorgeous.
 
Last edited:
But, the popular theory suggests that the Soviets did just that- put a 52,5mm lens on a focusing barrel designed for a slightly shorter one. Would it not be possible to assume that the Soviets made an LTM focusing helicoid that was pitched to work right with 52,5mm? If it's possible for them to make helicoids which will synch the lens's focusing to the rf cam for other focal lengths (like 85 or 135, or even 35 or 28), how much more difficult is it to design one for 52.5?
Click to expand...

I was just thinking the same. Movement of the lens from 1 m to infinity is 2,631mm for a f=50mm lens, and 2,881 for a 52,5mm lens. (note this 1m is the distance from the optical center towards the subject, not the readings on the lens which indicate the distance to the back of the camera)
 
The optics module of the LTM Sonnar, ZK Sonnar, and J-3 screws directly into the portion of the helical that has the RF cam. It translates 1:1 with the motion of the lens, does not reduce the action of the cam to correct for the difference in focal length. I have a custom made Contax to M-Mount adapter that has this correction, an arch cut into the RF cam. Roland made it.

I just received an export version of the J-8 that back focusses, and will be adding a shim to it. I'll report on the 1953 J-3 I bought on Ebay recently. The first 1953 J-3 required rebuilding and a new shim.
 
Last edited:
Sonnar Brian said:
Kim Coxon turned my shimming thread into a PDF and hosts it here:

http://pentax-manuals.com/repairs/j3service.pdf

I also out up a second set of instructions on the ziforums.com site:

http://ziforums.com/showthread.php?t=97

which shows what to do if the distance scale vs RF coupling is off.

I can't believe the '52 J-3 went up so high. My '53 J-3 was $93, shipped.

I would not change the element spacing unless shimming the lens does not work. I've changed spacing on two lenses, and shimmed dozens.
Click to expand...

Hi there Brian.
I have had very bad experience with a Julpiter 3 and my m240. Consistent back and front focus and I sent it back.
Some say that these version works well with my camera. Do you agree?
https://www.ebay.co.uk/itm?itemId=283990267126&du=1
 
https://www.ebay.com/itm/283990267126?hash=item421f2394f6

Yes- these work very well. I have two of them, both were perfect focus out of the box with my M9.

I was very excited and pleased with mine- the company asked me to do a write-up on it after I bought it. Might have been one of the first sold in the US.

https://www.lomography.com/magazine...-of-the-new-jupiter-3-plus-with-brian-sweeney

I told this to the person that took my order-

"So in the 21st century, we don't have flying cars--but you can buy a brand new Jupiter 3 that is better than ever. I'm calling it even."
 
You must log in or register to reply here.
Back
Top Bottom