Jupiter 11 135 f4 m39 ltm Focus issues

[fanam08]

Hello Everyone,

I´ve recently bought a Jupiter 11 on Ebay, for use with my FED 2 and Zorki 4K. As it turns out, when using my FED 2 and the Jupiter, I can´t seem to match both images when focussing on infinity, although with several other lens I own, I have no problem at all. Same thing with the Zorki. I´ve also noticed that the barrel markings for infinity don´t coincide. Meaning that the mark for infinity goes beyond the scale.
I´ve searched the web but with little luck. Can you provide some feedback on this?

Thanks,

Fernando

 

[Dez]

One thing in your posting is unclear- 'Same thing with the Zorki" . Does that mean it focuses incorrectly on the Zorki the same as it does on the FED 2? I am going to assume that is the case.
The lens has probably been taken apart and reassembled incorrectly. If so, it is not hard to fix. Focused at infinity, the focusing ring at the back of the lens should protrude approximately 6.8mm behind the surface of the mounting flange- not the end of the threads, but the surface that buts onto the lens mount on the camera body. If this is significantly different, I suspect the focusing helical, which is a multi-start thread, was assembled with the wrong start, a very easy mistake to make. How far past the fixed infinity mark does the moving mark go? If the infinity point of the lens is something like 1/6 of a turn wrong, that is almost certainly the problem.
Another thing you should check is where the lens is actually focusing. To do this take the back off your FED 2 and put matte Scotch tape across the rails over the film aperture, so the tape is in the exact plane that the film would be in. Hold the shutter open on B and with the lens wide open, and look at the image projected onto the tape to see how it focuses at infinity. I suspect you will not be able to turn it far enough to get a sharp image. This will definitely verify the "wrong start" theory.

Cheers,
Dez

 

[xayraa33]

Hello Everyone,

I´ve recently bought a Jupiter 11 on Ebay, for use with my FED 2 and Zorki 4K. As it turns out, when using my FED 2 and the Jupiter, I can´t seem to match both images when focussing on infinity, although with several other lens I own, I have no problem at all. Same thing with the Zorki. I´ve also noticed that the barrel markings for infinity don´t coincide. Meaning that the mark for infinity goes beyond the scale.
I´ve searched the web but with little luck. Can you provide some feedback on this?

Thanks,

Fernando

I am presuming that the lens is for LTM RF cameras and not the Zenit C SLR.

Make sure the lens cam is fully engaging the RF cam on the FED 2.

You can check this visually from the back on an empty camera set on B and holding the shutter open.

I had this problem on my Fed 2 when using a J-12 lens and I had to slightly push down the RF arm for the triangular RF cam to engage the thin lens tube cam.

You might have to adjust the RF for infinity on the FED 2 if you do this simple procedure.

 

[fanam08]

One thing in your posting is unclear- 'Same thing with the Zorki" . Does that mean it focuses incorrectly on the Zorki the same as it does on the FED 2? I am going to assume that is the case.
The lens has probably been taken apart and reassembled incorrectly. If so, it is not hard to fix. Focused at infinity, the focusing ring at the back of the lens should protrude approximately 6.8mm behind the surface of the mounting flange- not the end of the threads, but the surface that buts onto the lens mount on the camera body. If this is significantly different, I suspect the focusing helical, which is a multi-start thread, was assembled with the wrong start, a very easy mistake to make. How far past the fixed infinity mark does the moving mark go? If the infinity point of the lens is something like 1/6 of a turn wrong, that is almost certainly the problem.
Another thing you should check is where the lens is actually focusing. To do this take the back off your FED 2 and put matte Scotch tape across the rails over the film aperture, so the tape is in the exact plane that the film would be in. Hold the shutter open on B and with the lens wide open, and look at the image projected onto the tape to see how it focuses at infinity. I suspect you will not be able to turn it far enough to get a sharp image. This will definitely verify the "wrong start" theory.

Cheers,
Dez

Hi Dez,

Thanks for the quick answer. I´ve checked the back of the lens and it protudes just a little bit over 6.8mm like you said. I´ve measeured it and it protudes 8mm. Also the infinity mark is right were it reads "4" in the depth of field scale, to the right side, with the front of the lens opposite from you. Don´t know if this is too bad or not, what do you think?

Cheers
Fernando

 

[Dez]

So on your camera bodies, it focuses way PAST infinity according to the rangefinder, but the focusing scale on the lens does not make it to infinity, is that correct? Please do the Scotch tape test.

Cheers,
Dez

 

[fanam08]

So on your camera bodies, it focuses way PAST infinity according to the rangefinder, but the focusing scale on the lens does not make it to infinity, is that correct? Please do the Scotch tape test.

Cheers,
Dez

No, I must have explained myself wrong. It never reaches the infinity mark. The red marking on the scale, never reaches the infinity mark.
Meanwhile i´ll do the the scotch tape test.

Cheers,

Fernando

 

[Dez]

My error. I forgot that the lens turned clockwise to infinity. That small scale error can possibly be set down to normal Soviet precision in a consumer product or it could be caused by simply running out of thread in the focus mount- I suspect the latter. If the focus ridge comes out 8mm at infinity, the RF must be indicating that it is focusing far PAST infinity, correct? Please confirm. What is the lens distance indication when the RF says it should be at infinity?

Cheers,
Dez

 

[fanam08]

My error. I forgot that the lens turned clockwise to infinity. That small scale error can possibly be set down to normal Soviet precision in a consumer product or it could be caused by simply running out of thread in the focus mount- I suspect the latter. If the focus ridge comes out 8mm at infinity, the RF must be indicating that it is focusing far PAST infinity, correct? Please confirm. What is the lens distance indication when the RF says it should be at infinity?

Cheers,
Dez

Now i´m a little confused. The RF does not align the images on a subject at a great distance, meaning, it never reaches infinity. But with other lenses I have (Jupiter 8, Industar 26, Industar 22 and Jupiter 12) the alignment is dead on (with results shown on film). Also I´ve been checking the focus ridge on other lenses and they all protude about 8mm. Strange? Tomorrow in the morning I´ll be trying to do the test as you suggested. May it´ll shed some light on the matter. But thanks for the support, Dez!

Best regards,

Fernando

 

[wolves3012]

Just FYI, the cam on my J11 protrudes 6.25mm from the mount-face at closest focus (2.5m) and 7.50mm at infinity. The closer-focussing J8 moves from 4.40mm-7.50mm. If yours is not similar then it's possible it has been re-assembled incorrectly at some point in its life.

By the way, it's nothing unusual for there to be a slight variation in the RF indication of infinity between lenses. It should, however, be very slight and insignificant. I can mount J8, I61 etc and find they do not quite agree at infinity on the same body. RF images are very close but not in perfect alignment.

 

[fanam08]

Hi,

I did the test as Dez told me, the mate Scotch tape glued onto the film opening, and guess what?! The image was sharp at infinity! For me at least!!! I´ve tried it on the FED and the Zorki, and both the same result. Sharp! Nice method by the way! It´s interesting seeing the image appear in the tape, upside down of course!
I guess as Wolves3012 said, on the same body sometimes images don´t quite align on the RF, with different lenses.
Now for the ultimate test, let´s put some film in it!

Cheers to all

Fernando

 

[David Hughes]

Hi,

I have often thought that, with age and rough handling, the marks on these rings on the lenses will drift out of alignment. That applies to all the marking, imo. But it's only a guess.

Is there some way to loosen a screw or three and re-align them all; even aperture rings?

Regards, David

 

[wolves3012]

Hi,

I have often thought that, with age and rough handling, the marks on these rings on the lenses will drift out of alignment. That applies to all the marking, imo. But it's only a guess.

Is there some way to loosen a screw or three and re-align them all; even aperture rings?

Regards, David

Indeed there is "a screw or three" - usually three - to align the scales. It's a case of knowing which ones since not all lenses have them in the same places. For most but not all FSU lenses, you won't need to re-tap screw holes or anything drastic. Moving aperture-ring scales alone can be more troublesome, if it's possible at all on a particular lens.

Did you have any specific lens(es) in mind?

 

[David Hughes]

Indeed there is "a screw or three" - usually three - to align the scales. It's a case of knowing which ones since not all lenses have them in the same places. For most but not all FSU lenses, you won't need to re-tap screw holes or anything drastic. Moving aperture-ring scales alone can be more troublesome, if it's possible at all on a particular lens.

Did you have any specific lens(es) in mind?

Hi,

Thanks; nothing in mind but I assumed that they were assembled or fitted to a standard position and then fixed in place and three screws would seem to be logical. It would also explain the drift or creep people get with aperture rings, infinity marks and so on after a few years/decades use. And the tab alignment, of course.

And I assumed the lens mount would have the same treatment and the position of the 4 holes marked and then drilled. Like screw slots years ago, when oversized heads were used and then machined off with the slots' position marked...

Taking one to bits would answer the problem but it would raise a few more and so I left it until now.

Regards, David