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10-29-2009, 06:43 AM   #1
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Help getting this Jena Pancolar open?

Cute little 50/2 lens, with funky red DOF indicator needles that move when you set the aperture....

The only problem is the coupling between the aperture blades and the pin on the rear appears to be broken, so there is no way to stop down the lens. The little DOF preview button on the side of the lens doesn't work either.

Unlike most lenses, there are no screws on the mount area, or in fact, any screws at all except for the one shown in the photo just next to the DOF tab on the right hand side there.

If I could somehow get the back off it I figure I could dig down to the aperture blades and try to reattach or otherwise fix the coupling... I'd rather not disassemble the rear lens elements as this usually doesn't get you anywhere useful anyway.

Help!?

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10-29-2009, 02:20 PM   #2
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Unfortunately I do not have this Pancolar (this is the rare "star wars" version with bakelite focusing ring I think), but try to focus the lens to the shortest distance and then try to unscrew the extended lens barrel. Some lenses can be disassembled this way, for instance the 80mm f/1.8 Pancolar (which I have and which is also the easiest lens to work on).
10-29-2009, 03:38 PM   #3
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Peter, thanks for the hint with the Pancolar.

Welcome rjm,
I bet you have already vanished away in the depths of the cyberspace a.k.a. forum.manualfocus.org a.k.a. mflenses.com.

But, for the sheer satisfaction of typing, I guess you can't get this lens apart, cause only real specialists can do that - send it to me and I'll see if it's a hopeless case .-)

Really not, but there's two things you can try:

Unscrew the name ring - a back lens cap in the right size and the edge wrapped with double side sticky tape helps.

Try to unscrew the back end of the lens as a whole - this works on the Domiplan of the same era (and same country but not same factory).

Good byyyye (no echos in cyperspace)
Georg the kosmonaut
10-29-2009, 11:25 PM   #4
rjm
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Hi Georg and Asahiflex

No, I'm still here. :-) Still can't get the lens open. Funny thing is the single screw seems to loosen absolutely nothing.

The back seems like it might screw off, but does not budge. To my eyes the front barrel unscrewing when fully extended seems the slightly more likely.

I will stare at it some more before deciding which way to try first. It would be a shame to break it.

10-30-2009, 04:01 AM   #5
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One more word of caution:
If you start torsioning the front barrel on macro position, all the pressure goes on the two guiding rails inside, and only on the tips cause you're at macro. Could happen that those rails loosen and then you have another problem.
Going all the way out to macro is good for checking if there are tiny stop screws to loosen. Then, the unscrewing of the barrel I would always try at infinity position because then those rails are in fullest joint contact with the barrel (more support to counter the pressure).

The other thing you could try on any lens is to unscrew the back lens - depending on how and where you are able to apply torsion you can luckily end up with unscrewing the whole back lens unit (so you'd end up on the rear part of the aperture) or only the back retaining ring.

Last resort: You could apply good zipper fluid into the opening of the stopdown lever on the lateral side (where the screw is) and see if you can get the blades moving - leave the lens with the lever on the bottom to not spill the fluid all over into the lens.

That's what you get when you come back from cyberspace :-)
Georg

Last edited by georgweb; 10-30-2009 at 04:10 AM.
11-02-2009, 09:08 PM   #6
rjm
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Thanks for all your help but I've decided this is best left to someone with more experience that I. I've put the lens on ebay from $1, its up from Nov 3. Just search for "pancolar" if you want to grab it.
11-16-2009, 01:11 PM   #7
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Hi folks - I have 50mm and 80mm f1.8 pancolars, both with malfunctioning blades, so i'm planning to disassemble them - I've taken the backs off and on, and got my head around the aperture and focus controls, but can't get the front elements off the aperture section - should i have unscrewed this first, while the lens was assembled? as mentioned above i'd worry that that would put all the turning force on the two focus rails..

Any tips? gotchas?
Thankyou
11-16-2009, 01:20 PM   #8
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QuoteOriginally posted by Mark Littlewood Quote
Hi folks - I have 50mm and 80mm f1.8 pancolars, both with malfunctioning blades, so i'm planning to disassemble them - I've taken the backs off and on, and got my head around the aperture and focus controls, but can't get the front elements off the aperture section - should i have unscrewed this first, while the lens was assembled? as mentioned above i'd worry that that would put all the turning force on the two focus rails..

Any tips? gotchas?
Thankyou
I only have experience with the 80mm f/1.8 Pancolar - I have disassembled three of them including mine, and this lens is one of the easiest ever to work on.

I guess by now you already have figured out how to disassemble the back part. When you have removed the mount then removing the back group is easy: just turn the small lens barrel counterclockwise and it unscrews, exposing the diaphragm blades.

The front group can be disassembled as follows: just grab the front ring and turn it counterclockwise. This ring (with the lens information ring inside it) can then be screwed off. Now the barrel with the front group is exposed. Just grab this like the back group and unscrew it counterclockwise.

Tadaa! You are now left with the focusing helicoid and the diaphragm assembly, which can be cleaned with some naphta.







11-16-2009, 01:36 PM   #9
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Tadaa, (you must have a MacIntosh .-)
Thanks for sharing Peter!
11-18-2009, 03:53 PM   #10
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QuoteOriginally posted by Asahiflex Quote
just grab the front ring and turn it counterclockwise. This ring (with the lens information ring inside it) can then be screwed off.
Yeah thanks for the instructions and photos! It's this part above i'm worried about - I get no sense that the front ring of my lens is keen to come undone, and am hesitant to apply maximum force (turning against my other hand holding the focusing ring) until someone (perhaps yourself!) convinces me that such an action doesn't stress the focus rails or internal arrangements...

Thanks
11-18-2009, 04:03 PM   #11
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well i bit the bullet and twisted.... and it came off fine. Nice one, thanks all.
11-23-2009, 03:03 AM   #12
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QuoteOriginally posted by Mark Littlewood Quote
well i bit the bullet and twisted.... and it came off fine. Nice one, thanks all.
Sorry, I missed your post but great that it worked out well. How's the Pancolar doing now?
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