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Rlc
Tinkerer
Username: Rlc
Post Number: 20
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 23, 2007 - 08:43 am: | 
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I recently aquired this Pentacon ZI.(Same as Contax D ???) The first curtain stops at about 1/4" from completing it's travel on slow speed and Bulb settings. A gentle nudge allows it to complete it's travel.
Does this suggest a need for lubrication of the first curtain spindle? If yes, can anyone help with information on this procedure?
Thanks for any help. Richard. |
Dgillette4
Tinkerer
Username: Dgillette4
Post Number: 101
Registered: 04-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 23, 2007 - 11:21 am: |
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Hello Richard: It could need clean and lube. Also if that doesen't work you may have to check spring tension on curtain. Don |
Rlc
Tinkerer
Username: Rlc
Post Number: 21
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 23, 2007 - 05:40 pm: |
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Thanks Don. Have you, or has anyone else on this forum, performed this operation on a Pentacon ZI ? I have searched for details but alas no success.
I did find that by warming the camera very slightly in front of a space heater the shutter will operate properly at the slow speeds and B. When camera cools down to ambient temp the same problem re-occurs. Thus my conclusion that it may be congealed lubricant on the curtain shaft.
Thanks for any and all comments regarding getting to the inside to service the curtain spindles. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 416
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 23, 2007 - 06:47 pm: |
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Sure! It is NOT lubricant. This is very common with Pentacons and some other cameras of that age; the curtains harden to the point that the mechanism can no longer move them, and you need to replace the curtains. The basics are at http://rick_oleson.tripod.com/index-87.html
(kind of surprised you didn't find it - if you type "contax pentacon shutter curtain" into Google, this comes up as the first entry)
For more details and higher resolution sketches, email me at [email protected] |
Rlc
Tinkerer
Username: Rlc
Post Number: 22
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 24, 2007 - 08:05 am: |
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Rick; I am greatly indebted to you for your insight into my problem with the Pentacon.
I notice one small screw head under bottom right corner of film gate. Does this screw have to be removed as well as the four screws which are securing the gate?
I have reviewed you excellent "tripod" site and am fascinated by your vast warehouse of knowledge regarding so many diverse camera subjects.
Have there been any attempts to recondition the existing curtain material to restore it to original flexibility?
Thanks again for the generous sharing of your expert knowledge. Richard. |
Glenn
Tinkerer
Username: Glenn
Post Number: 200
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 24, 2007 - 10:28 am: |
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There is no way of reconditioning 'perished' curtain materials. You have to stripdown the camera to reach the damaged curtains, so replacing them is not much more work anyway. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 419
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 24, 2007 - 03:17 pm: |
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I don't think I've ever encountered the 5th screw you're referring to. If you could email me a photo of it maybe I could figure it out.... all of the PentaContaxes I've dealt with just had the 4 screws to pull out. You do have to fiddle a bit, the gate will not come off until the slot at the top of the sprocket shaft is aligned perfectly fore/aft.
The curtains are stiff because the rubber coating on them has hardened. The only way to make them flexible is to crumble the coating so badly that the curtains will bend again, by which point they block light about as well as a window screen. I did this on my very first Contax S and confirmed that the mechanism was okay, but it was no use for photography until the curtains were replaced. |
Rlc
Tinkerer
Username: Rlc
Post Number: 23
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 26, 2007 - 12:00 pm: |
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Thanks Rick. Photo has been emailed. Also need to know a source for high quality curtain material. I have read some negative comments regarding Microtools as a source.
Richard. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 422
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 26, 2007 - 07:02 pm: |
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Hi Richard! I haven't received your email, or maybe it got snagged in my spam filter and I missed it. Please re-send. [email protected]
Micro-tools has a range of products from very good to pretty shoddy - experience can vary widely. Generally I have been pleased with them, but not 100%. In particular, avoid their RED shutter curtain material, as it is not light-tight! Other than that, the Pentacons are pretty forgiving... Micro-Tools' black stock should be fine. I like to use darkroom curtain fabric, but I don't know if that's even made any more. |
Mikel
Tinkerer
Username: Mikel
Post Number: 59
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 26, 2007 - 08:48 pm: |
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Not to ever disagree with Rick, who is helpful to everyone including me.
But I would say that I have had these cameras with completely stiff and unusable curtains but also have found them with supple like-new curtains which I had no reason to believe were not original. Your mileage may vary. Things were fairly variable in the former East Germany.
When replacing curtains in these classics, I use material from a film changing bag. Mine is a Spiratone I bought for $12 or so on the bay a few years back. It has furnished some Contax and Exakta replacement curtains which satisfy completely. |
Rlc
Tinkerer
Username: Rlc
Post Number: 24
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 26, 2007 - 09:09 pm: |
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Thanks Mikel & Rick.This curtain seems quite flexible and I see no rubber coating on either side of it. It does have one very small(Less than 1/2mm hole) which I had hoped to repair with a dab of black liquid tape.
I found this curtain material listed from Micro-Tools at:
( http://www.micro-tools.com/store/item_detail.aspx?ItemCode=SCM )a very reasonable price for 9" X 11". Would this be a suitable material?
Rick I have re-sent the picture of the fifth screw in the film gate to your email.
Thanks for the help from all.
High Regards, Richard. |
Rlc
Tinkerer
Username: Rlc
Post Number: 25
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 30, 2007 - 07:13 pm: |
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Success! Thanks to Rick, Mikel and all others.
After removing the film gate I applied a drop of watch oil to all four curtain spool pivot bushings, using a long hypodermic syringe.
The first curtain now completes it's travel at all slow speeds and bulb. Slow speeds seem accurate and operating properly.
I have repeated the test dozens of times at all speeds and with varying temperatures, from very cold to warm, with 100% success.
Hope this means that all fast speeds are also accurate since no adjustments were made???
There is no capping (Fading) at 1/1000.
Now to experiment with black liquid tape, (Perhaps Thinned) on a piece of scrap cloth before patching the very small pinhole in curtain. Thanks, Richard |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 424
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 30, 2007 - 08:27 pm: |
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Sounds like good news! In the 20+ years I've been working on these, I don't think I've ever found one that as hanging up due to a lubrication problem in the curtain spools. Just goes to show, you've never seen all of them.
Your speeds are probably accurate - this timing system is very robust, practically never needs adjustment. Apply the liquid tape stuff to the fabric side of the curtain, it will adhere to the fibers better than to the rubber surface on the other side. |
Glenn
Tinkerer
Username: Glenn
Post Number: 208
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 31, 2007 - 03:23 pm: |
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Ric,
When you removed the film gate, did the inside of the camera look clean? I just wonder if somebody has been a bit liberal with the Ronsonol, washing all the lube out and not replacing same. Obviously the shutter mechanism was lubricated on assembly, thus it does not run properly dry. |
Rlc
Tinkerer
Username: Rlc
Post Number: 28
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 31, 2007 - 04:55 pm: |
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Glenn; Yes the interior of the film gate was spotlessly clean except for one tiny bit of film from a broken film sprocket hole. I first thought this may have been causing the problem but upon reassembly and testing the problem still existed. I removed the gate again and applied the watch oil.
We must remember that this camera is over 50 years old. Who can say what type of lube was used originally? Richard. |
Mikel
Tinkerer
Username: Mikel
Post Number: 60
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 01, 2007 - 08:36 pm: |
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"Who can say what type of lube was used originally? Richard."
Well, that is a good point. Whatever is in there I usually clean out with some Ronsonol and replace with some Nyoil.
It was probably variable. But these old Contax S & D derivatives are amazing historic cameras.
It is not well known today, except for the likes of Herbert Keppler of Popular Photography, what these cameras meant in the early 1950's.
He recently did a column on the Zeiss Biotar 2/58 of the early 50's. It was an exceptional review. He posted a portrait of Alfred Eisenstadt taken with a Biotar. He sent the lens downstairs to the lab at PopPhoto and had it tested against the latest Nikkor 50/1.8.
I would not have had the courage to do that.
They published the results.
With it's single coating and glass bubbles, it equaled or beat the Nikkor in all of the tests. |
Rlc
Tinkerer
Username: Rlc
Post Number: 30
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 10, 2007 - 02:22 pm: |
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Two problems solved. Curtain working fine, thanks to help from all. I successfully repaired the pin hole in curtain with a dab of black model paint. I found that liquid tape was far too thick when tested on scrap piece of fabric. After thinning it became translucent. Now I am wondering if very stiff focusing (from congealed lube)can be corrected without disturbing the focus. It seems that the name ring in front must be removed with friction driver. I have searched for details but have had no luck.
Help! Rick and Mikel. Thanks,Richard. |
Rlc
Tinkerer
Username: Rlc
Post Number: 31
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 10, 2007 - 02:27 pm: |
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P.S. The lens is "C.Z.Jena Biotar 1:2 f=58.
Richard. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 428
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 10, 2007 - 03:34 pm: |
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Hi Richard:
I have some notes on CZJ lenses here: http://rick_oleson.tripod.com/index-81.html
.... your Biotar's construction is probably closer to the 80mm Tessar than the 58 Biotar in the sketches. Write me if these are unclear or inadequate and I'll see if I have anything better.
I'm a little surprised that the liquid tape wasn't satisfactory; I have 2 cameras here that I have patched up (large areas) with that stuff and have never gotten around to doing a replacement, they seem to be fine. Glad the model paint worked.
A little trivia on the history of the Contax... in 1951, it was listed here in the US at $475. I'm pretty sure that this made it the most expensive 35mm camera you could buy at that time. Small wonder then that it didn't sell in huge numbers (on top of all the political and legal complications of the time).
rick  = |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 85
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 11, 2007 - 04:50 pm: |
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Hello Richard,
Since your camera is a "Pentacon" rather than the Pentacon F or FM, your Biotar is presumably the pre-set version rather than the semi-auto. This is a pity, because it is very easy to separate the focus-mount from the optics on the semi-auto, but very, very hard on the pre-set! You really have to remove the rear optics to get at the retaining ring, and even then it is pretty difficult.
I made notes and took pictures when I did mine, and made an html page as an experiment. It is still a bit of a work-in-progress, but I have uploaded it this evening in case it helps:
http://www.ydo.abelgratis.co.uk/biotar_ps.html
You won't have to do all of it if all you need to do is regrease the helical. For a start you can skip step 1!
Any comments or suggested improvements would be welcome.
Best of luck! |
Rlc
Tinkerer
Username: Rlc
Post Number: 32
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 12, 2007 - 07:37 pm: |
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Thanks Rick & Steve. Yes Steve my lens is pre-set diaphragm type. It looks the same as yours on your page.I'm awed by the pics and text on your page!
I find that looking into rear of lens (At minimum close focus setting) I can see the helical (very fine threads). Also there are two rectangular bars approx. 3mm wide 180 degrees apart. (Guide bars?)
I can access the helical threads without disassembly. Wondering if a solvent (naptha or acetone) saturated, lint free, swab carefully applied to the threads would remove some of the grease & help reduce the friction? Richard. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 429
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 12, 2007 - 09:42 pm: |
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I love that spanner, Steve! I don't know if I've had the 58/2 preset apart, I don't recall it being as hard as it looks so that probably means I haven't done it.
Richard, acetone generally is more trouble than benefit. Naphtha will clean out some of the old grease, and you can relube the parts that you can reach... but you probably won't be able to reach enough that way to do a whole lot of good. A non-rotating focus mount has 2 sets of helicals: the stationary female thread in the rear barrel, the stationary male thread on the lens, and the focus ring which has both male and female threads on it to engage both of the above. Reaching part of one of the helicals only takes care of a small percentage of the thread area. Still, sometimes it does help.
The rectangular bars are, as you guessed, guide bars to keep the non-rotating parts of the lens from rotating as you turn the ring in between them. If you can remove the bars you can unscrew and separate the helical (if you do, take extreme pains to document exactly how everything was together and the exact relative orientation at the moment the pieces separate... putting it back together is harder than getting it apart). |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 86
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 13, 2007 - 03:26 am: |
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Rick is absolutely right. Solvent will only have a temporary effect, if any, and may make things worse.
One of the several "interesting" features of this lens is that the helical guide bars actually form part of the focus-mount (the rear-most part of the lens), so they are not detachable - hence my convoluted description of how to get the helical apart! Also, being quite thin aluminium, they appear very fragile. The focus on my lens was almost solid, and I'm surprised they survived my attempts to turn it.
I'm still a bit of a beginner myself lens-wise, but I'd have to say that if you haven't already stripped a few lenses, Richard, you'd have to be a brave (or foolhardy!) man to start on this one! If you do, take it very, very slowly, and shout (via this thread) if you run into problems.
The semi-auto Biotar is a totally different prospect. Just like Rick's diagrams, you take out the easily accessible large retaining ring at the rear and the optics separate from the mount. |
Rlc
Tinkerer
Username: Rlc
Post Number: 33
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 14, 2007 - 03:08 pm: |
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Being niether brave but only occaisionlly foolhardy I have decided to leave well enough alone, even after my recent cataract surgery I would not venture to undertake such a daunting task.
I scrubbed the visable helix threads with Ronsonal and applied Watch Oil with slight decrease in friction noticed on focusing.
It is now time to load with film and hope for good results.
Captain Jack's web page on "Contax/Pentacon" indicates that the "Contax" name was reserved for the European market while the name "Pentacon" was used for the American market. Can you verify this. McKeown's price guide sheds little light on this. My model has the flash sync. connection on top and has the small knobs. I have searched eBay listings both current and past (Closed) listings and can find none listed. Not too popular apparantly, perhaps due the high retail price when new as Rick noted.
Another matter of confusion; Two different S/N's appear, one at bottom outside on the back the other inside on the body. Maybe back has been replaced??
Well, it's time for this old man to close this very lengthy thread with my sincere thanks to you generous souls, Rick, Steve_s and others who have so unselfishly dedicated themselves to our
education and preservation of these marvelous mechanical works of art. Richard. |
