Jupiter 9 calibration

[fgianni]

Hi All, I have a bit of a problem here: a few days ago I posted a message asking for help about my LTM Jupiter 9 (the 85m mf2) focusing about 2-3 inches behind the rangefinder indication on my RD-1 with adapter at the closest focusing distance, and was advised to contact Oleg.

I sent Oleg an e-mail asking if he could service my J9, but he replied saying that it would be difficult to check without my camera, of course I 'd rather not send him my RD-1.

Essentially it might be a problem with adapters (I tried with two) since it looks as if the lens does not get far enough inside the camera, probably about 1mm would do the trick, the camera is ok since the RF is spot on with other lenses.

Are there different adapters that could do the trick, or is there somewhere a simple guide on how to calibrate a J9 lens, so I can try to do it myself.

I dont want to send the lens to Oleg for servicing and later discover that is is a problem with the adapter/camera combination.

Any help would be greatly appreciated.

 

[fgianni]

You could use some thin copper tape to build up the RF coupling to the camera. The real problem is the J9 is built to the Contax 52.3mm standard. The RD-1 uses the 51.6mm Leica standard. Building up the cam has the same "net effect" as moving the lens out. You are essentially using the len's helical for the stand-off. The distance scale will be inaccurate, but if you use the RF patch for focus you will be okay.

Hmm any more details on the procedure please? (I am a bit of a newbie in the RF area so I don't really understand what you are talking about) :bang:

If I understand what you are saying looks like my jupiter should get about 0.7 mm more inside the camera, to have a distance of 51.6 mm from the sensor plane, it would be nice if someone simply made such an adapter 😉

 

[chenick]

How important is that distance, and are all Russian LTM lenses built to the Contax standard?
I have a 50mm F1.5 Nokton for my Bessa, which is huge, so I decided that a smaller Russian lens would complement it nicely... I decided on an I-61, as the F2.8 max aperture would be slightly more forgiviing of focusing than an F2 Jupiter 8...

Anyway, my real question is, is the I-61 usable at close distances without modification?

Cheers!
Nick

 

[Nickfed]

How important is that distance, and are all Russian LTM lenses built to the Contax standard?

Anyway, my real question is, is the I-61 usable at close distances without modification?

Cheers!
Nick

I think you should should reflect on the logic of the statement before you get too worried about this. You will rapidly come to the conclusion that there isn't any.
The LTM and the Contax mount are completely different and there is no means, method, reason, or necessity to try to adopt the "standard" of one to the other.

I recognise that some I-61s may be badly made or butchered by some repairman in their long career, but essentially nonetheless, the real answer to your real question is that the I-61 is just as usable at close distances as any other LTM lens. If you find that you are consistently shooting at distances like one metre, and sweating over the accuracy, you can always, after recovering from the financial outlay on the I-61, namely $5, do what you should have done in the first place, get an SLR.

Cheers, Nick!
Nick

 

[fgianni]

An aperture of F2 on a 52.3mm lens should cover the difference in focus on a RF for the Leica. The telephoto lenses do not have enough DOF when used wide-open to cover the difference. The J3 at F1.5 is also a problem when used wide-open, but mine was much worse than it should have been.

Which is probably why the focus on my jupiter 12 seems spot on.

 

[Hektor]

Brian, I've checked fgianni's RD-1 with a noctilux wide open at about 4 feet and I think it's spot on focus. - just in case this helps. Regards John C.

 

[Hektor]

Yeah,..... One thing that's puzzling(sp) me is that the pitch of the focussing helix is matched to the focal length of the lens if the cam has a plane surface,.... then, on the russian cameras you can correct a minor deficiency at close range by adjusting the foot on the cam follower. This facility doesn't exist on leica bodies,.. they seem to modify the plane of the cam.

Therefore which situation is appropriate here ?.......... Hmmmmm.

Regards JC.

 

[Hektor]

Thinking about it a bit more i reckon the "russian" issue is that their QC is not good enough to keep the focal length consistent on all samples, which means some of the focussing helices are slightly inappropriate, - hence the need for the adjustable foot on the cam follower.

Leica and others with better QC and a choice of helix available just don't need it !

 

[Hektor]

No,..... I've changed my mind,.... I think the FSU adjustable foot is entirely to do with the rangefinder geometry, not the lens,... Oh well,....durr,.... brain hurts !!

 

[Nickfed]

Now you are getting it......... The next thing to wonder is, in the light of other adjustmnents more available, is it actually supposed to be adjustable? Don't even bother asking, how, by whom, and under what circumstances.

 

[Hektor]

.............ok.

 

[fgianni]

So anyone has details, instructions and/or pictures on how to build up the RF cam on the lens to operate correctly?
Please make it simple, when it comes to DIY I have two left hands.

Hektor, are you still on for the camera fair on sunday?

 

[Solinar]

Sorry to be the bring this up, but I'll bet dollars to donuts that your Jupiter 9 will no longer focus properly at or near infinity once you do this modification.

 

[fgianni]

Currently, the lens' focus is farther than what is should be. It basically will focus "To Infinity and Beyond" (To quote Buzz Lightyear). If done correctly, it will focus to infinity. The J9 that I sold to Oscar focussed properly and would focus to infinity on my Canon 7.

Okay, I cannot remember: Does the RF cam on the J9 "rotate" with focus, or does it move in-out without rotating? If the latter, putting a layer of copper tape or something similar on the portion of the RF cam that is at the top of the lens (makes contact with RF pickup) will work. If the whole thing rotates, you need a thin ring of material.

Are you ready to buy a Nikkor 8.5cm F2 yet?

This must be frustrating for you. Must shoot some photo's, need to get SB29 on Nikon E3 with the Micro-Nikkor for these shots.

It does not rotate, has it got to be copper? Or anythng that increases the thickness will do?

 

[Nickfed]

....Paint?

 

[Hektor]

I think I've got some of that self adhesive copper tape somewhere, at least I did about twenty years ago. I'll look for it and bell you if I find it Ian. Yep OK for Sunday, probably see you there 'cause I'll be going at 7.

 

[Hektor]

Found it !!!!! ....

Brian, mine says 3M Scotch Electrical tape, electrical specialities division 1739.7
was supplied by Farnell, part No 751-522 description 1194: foilsheilding plain copper DN742306.

in case it's of interest !

 

[fgianni]

Yep OK for Sunday, probably see you there 'cause I'll be going at 7.

Lucky you, with my kids still waking me up at least 3-4 times per night I won't be out of bed until 9 on sunday, probably I'll be there at about 10:30

 

[fgianni]

Ok I tried with insulating tape, and one layer did the trick, just needed to have a good look at the lens and see haow it worked I guess.
The problem with insulating tape is that, being plastic will probably deformate with time, I will have to find some of that copper tape, I tried Wickes but they don't stock it.

 

[Hektor]

I,ve got some.......you can have a piece.