vicmortelmans
Well-known
I recently took a dive into LTM-camera-space with the Zorki 4. It came with a Jupiter 8. I added a Jupiter 3 and an Industar 22.
The Jupiter 8 had some fungus on the front element inside. Also both Jupiter's focus setting could be improved, so I took the lenses apart for cleaning and readjusting.
They have similar design (the main difference being that the aperture dial doesn't move when focusing on the Jupiter 3, while it does move on the Jupiter 8).
ALCOHOL
Cleaning fungus was done using medicinal alcohol and generic lens cleaning fluid (used the alcohol because fungus is organic and I thought it might work as well on bacteria as on fungi). I was surprised that I could clean it at all, since I assumed that the fungus would damage the lens coating in some way, but it's completely restored!
VASELINE
Then the focusing and aperture rings needed a bit of grease... I just used Vaseline for that job! I know there are special greases available, which are not affected by heat, moist or whatever environmental influence. I'm wondering how long it will last. Since the Vaseline is also medicinal, I don't think it will harm anything, so whatever happens (e.g. creeping allover the lens internals in hot summer), I assume it can be rectified. (hmmm. vaseline on aperture blades... probably not a good thing).
PAPER FILM
Now for focus calibration. As a matte screen (to judge the image as it would be projected on the film) I used a semi-transparant paper film (used in printing business and for technical plans).
Both Jupiter-lenses come apart in two major parts, the front element containing all lenses and the back element containing the focusing helicoid mechanisme. Both parts screw together. Focusing adjustment is about how far the front element is screwed into the back element (correct me if I'm wrong).
First, you have to check if the back part is set OK. For this, you don't need the front part being screwed in, it's more about checking the rangefinder cam setting. If you set the lens focusing ring to infinity, the rangefinder should be aligned on far distant objects. If not, the rangefinder needs adjustment first! This test should be OK for all your lenses! If you get different results with different lenses, I think you will have a hard time adjusting everything to normal! Make sure to pick a *real* far distant object: 10 or 20 m is not enough!
RUBBER BAND
Then, the lens has to be put together, such that if you set the focusing ring to distance X, the image of an object at distance X is in focus on the matte screen. For this test, it's easier to work on a nearby object (e.g. 1m). There are some nice test patterns on the web that you can print out an stick to the wall.
There was a distance ring in the Jupiter 8 that had no set screw and one in the Jupiter 3 with set screw. My test showed that on both lenses, I needed to increase the offset between front and back element. This would mean: have a larger distance ring (exactly 1 turn wider) for both lenses. Of course, I don't have that kind of material available.
This is the solution I came up with: I took a househould rubber band and twisted it around the front element's thread, thus replacing the original distance ring. Then I could screw the front element into the back element, and when reaching the point where the screwing should have been stopped by the distance ring, I now have a wide range where screwing is resisted by the rubber band's elasticity, firm enough not te be un-set by normal operation.
Also for this solution, I'm aware it's probably only temporary, until the rubber band starts to deteriorate... But then there's a next 0.1c rubber band...
SOME LUCK
now, the focusing should be ok for all distances, from 1m to infinity. If not, you're in bigger trouble!
I don't think people will offer me their elmars for repair... whatever, let's try out those lenses as long as they work!!
Groeten,
Vic
The Jupiter 8 had some fungus on the front element inside. Also both Jupiter's focus setting could be improved, so I took the lenses apart for cleaning and readjusting.
They have similar design (the main difference being that the aperture dial doesn't move when focusing on the Jupiter 3, while it does move on the Jupiter 8).
ALCOHOL
Cleaning fungus was done using medicinal alcohol and generic lens cleaning fluid (used the alcohol because fungus is organic and I thought it might work as well on bacteria as on fungi). I was surprised that I could clean it at all, since I assumed that the fungus would damage the lens coating in some way, but it's completely restored!
VASELINE
Then the focusing and aperture rings needed a bit of grease... I just used Vaseline for that job! I know there are special greases available, which are not affected by heat, moist or whatever environmental influence. I'm wondering how long it will last. Since the Vaseline is also medicinal, I don't think it will harm anything, so whatever happens (e.g. creeping allover the lens internals in hot summer), I assume it can be rectified. (hmmm. vaseline on aperture blades... probably not a good thing).
PAPER FILM
Now for focus calibration. As a matte screen (to judge the image as it would be projected on the film) I used a semi-transparant paper film (used in printing business and for technical plans).
Both Jupiter-lenses come apart in two major parts, the front element containing all lenses and the back element containing the focusing helicoid mechanisme. Both parts screw together. Focusing adjustment is about how far the front element is screwed into the back element (correct me if I'm wrong).
First, you have to check if the back part is set OK. For this, you don't need the front part being screwed in, it's more about checking the rangefinder cam setting. If you set the lens focusing ring to infinity, the rangefinder should be aligned on far distant objects. If not, the rangefinder needs adjustment first! This test should be OK for all your lenses! If you get different results with different lenses, I think you will have a hard time adjusting everything to normal! Make sure to pick a *real* far distant object: 10 or 20 m is not enough!
RUBBER BAND
Then, the lens has to be put together, such that if you set the focusing ring to distance X, the image of an object at distance X is in focus on the matte screen. For this test, it's easier to work on a nearby object (e.g. 1m). There are some nice test patterns on the web that you can print out an stick to the wall.
There was a distance ring in the Jupiter 8 that had no set screw and one in the Jupiter 3 with set screw. My test showed that on both lenses, I needed to increase the offset between front and back element. This would mean: have a larger distance ring (exactly 1 turn wider) for both lenses. Of course, I don't have that kind of material available.
This is the solution I came up with: I took a househould rubber band and twisted it around the front element's thread, thus replacing the original distance ring. Then I could screw the front element into the back element, and when reaching the point where the screwing should have been stopped by the distance ring, I now have a wide range where screwing is resisted by the rubber band's elasticity, firm enough not te be un-set by normal operation.
Also for this solution, I'm aware it's probably only temporary, until the rubber band starts to deteriorate... But then there's a next 0.1c rubber band...
SOME LUCK
now, the focusing should be ok for all distances, from 1m to infinity. If not, you're in bigger trouble!
I don't think people will offer me their elmars for repair... whatever, let's try out those lenses as long as they work!!
Groeten,
Vic
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