largedrink
Down Under
Another great source of information about Zeiss is the complete set of Zeiss Historica issues on Mike Eckman's website:
https://mikeeckman.com/zeiss-historica/
https://mikeeckman.com/zeiss-historica/
flavio81
Well-known
Wow, this was a really good read, i glanced over some issues.
Thus I learned about the Contax post-war prototypes with 50/85/135 built-in finders, and lenses like the 28/2.0 and 85/1.4 that were completed and ready to put in production (for the Contax) but that Zeiss decided against producing since they were going to concentrate on the Contarex system. A 28/2.0 in the mid 1950s would have been quite a shock and no doubt would have given a renewed competition against Leica with its new M3.
Other issues also tell us that they were much more lenses (rare) available for the Contax RF mount, like even a Voigtlander Nokton 50/1.5...
Well, this is off topic, but many thanks for the link!
largedrink
Down Under
I found some more CLA information in Camera Maintenance & Repair Book 2 by Thomas Tomosy, Amherst Media 1997.
Update: these were for the Contax II/III not IIa/IIIa so deleted to avoid confusion.
Update: these were for the Contax II/III not IIa/IIIa so deleted to avoid confusion.
flavio81
Well-known
Yes, but this is for the Contax II and III. This thread is about the Contax IIa and IIIa, which have an entirely different shutter with nothing in common. Even the operational principle is different.
largedrink
Down Under
Oops sorry, I updated the post to avoid confusion.
Philip Whiteman
Well-known
Can I take us back to getting the higher shuttter speeds of a IIa/IIIa to work? As mentioned on the main Contax thread, I have recently picked up a colour-dial IIa that was in almost as-new cosmetic condition but had a non-functioning rangefinder and shutter that ran it only one speed. Doing a minimum strip-down and just carefully cleaning and lubricating the shutter components under the top plate, and lubricating the rangefinder prism pivot proved a 90% fix, as I had hoped it would. However, at 1/1250th the shutter travels closed and it does the same randomly at 1/500th. I am not sure this is simply a case of the inaccessible bearings needing to be lubricated - obviously something to try and eliminate as the problem - or it being a better (or even good) idea to loosen the ring nut and adjust the disc on top of the first curtain to delay release of the second. Has anyone tried this/have a cautionary tale of why you shouldn't?
flavio81
Well-known
Hi,
When you have a camera that has no signs of having been tampered with on the inside, and is just malfunctioning due of lack of lubrication or lack of cleaning, never ever change the calibration on it. That is, never ever adjust anything.
You would always first do a proper cleaning and lubrication. I wrote previously, before speaking about calibration: "assuming the shutter and gears were properly cleaned and lubricated"
This means doing a almost full strip-down(*) of the shutter assembly itself, cleaning the parts, ideally using an ultrasonic bath, otherwise by manual cleaning. It's important that the inner springs (on the shutter itself) to be cleaned and lubricated, as well as it's important that the curtain ribbon isn't frayed. Then, of course, apply very light lubrication on spindles and moving stuff using a watch oilier.
(*) The timing cams and sprockets should be also cleaned and lubed, and I say this ought to be made with them in place, because the alignment of the high-speed cam requires a Zeiss alignment jig so that's what makes doing a full-strip down not a doable idea. So better to do a Clean-lube without messing with the calibration of the high-speed cam and associated components.
Assembling the shutter back again and increasing tension very slowly until getting good 1/25 (assuming the governor was properly cleaned), should restore operation of fast speeds.
Again, no high-speed cam calibration should be ever attempted before being absolutely sure all parts linked to curtain movement are completely smooth and lubed.
Philip Whiteman
Well-known
Sound advice, Flávio. Clearly, I need to strip down my camera further: deep breath...
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Philip Whiteman
Well-known
Having taken the top plate off again, I note that both shutter discs/cams are marked with light scratches across shaft and disc, suggesting evertything is aligned correctly, further emphasising your point
Coldkennels
Barnack-toting Brit.
I recently picked up a Contax IIa in decent condition, but shutter testing reveals tapering on the top two speeds:
From those in this thread who are much more well-versed in the arcane ways of the Contax than I am, what's the prognosis here? As 1/250 seems okay and shutter speeds otherwise seem fairly accurate/consistent across the board, is this likely to be a simple clean and relubricate of gears under the top plate, as some of this thread suggests?
From those in this thread who are much more well-versed in the arcane ways of the Contax than I am, what's the prognosis here? As 1/250 seems okay and shutter speeds otherwise seem fairly accurate/consistent across the board, is this likely to be a simple clean and relubricate of gears under the top plate, as some of this thread suggests?
Seboyes
Newbie
Hi everyone new member here. Just thought I'd add to this resource with information I've received from Henry Scherer of ZeissCamera.com.
On the tension of the shutter curtains, several things should be noted. Firstly tensioning the curtain will decrease the top 3 speeds therefore having a lower curtain speed is ideal. The method for which Henry told me was to tension the shutter just enough that it does not hang loose and then completely assemble the camera. after assembly, the shutter can be tensioned until there is no blanking at 1/1250.
Something else to be noted is the spring mechanism in the curtain assembly works as basically an analog computer that is working out the way the two curtains share force, this process takes time. It may be the day after your tensioning the 1/1250 may blank again therefore it is necessary to tension until the 1/1250 stops blanking again. Henry has said that he has had some cameras which will keep changing even 6 months later.
Another point made to me was that due to Leica's patents, Contax had a very hard time designing around the Leica-type shutter, this led to the creation of the vertical slat shutter observed in Contax cameras. The shutter functions differently from a Leica-type shutter as instead of passing the slit of light over the film plane the whole curtain assembly remains open the whole time of the exposure with the second curtain coming down like a blade to end the exposure. This design means many shutter testers can not read the speeds correctly. A good 1/1250 may actually come up as around 1/800 on a modern shutter tester.
The last bit of info I gleamed from Henry was that due to the complications of the adjustments cameras would come out of the factory with incorrect high shutter speeds.
I hope this information is helpful to anyone brave enough to delve into these cameras but I will pass one piece of advice I got from Henry: When you are working on a Contax if you don’t know exactly what you are doing and how to get out of it if it should go wrong then don’t do it.
On the tension of the shutter curtains, several things should be noted. Firstly tensioning the curtain will decrease the top 3 speeds therefore having a lower curtain speed is ideal. The method for which Henry told me was to tension the shutter just enough that it does not hang loose and then completely assemble the camera. after assembly, the shutter can be tensioned until there is no blanking at 1/1250.
Something else to be noted is the spring mechanism in the curtain assembly works as basically an analog computer that is working out the way the two curtains share force, this process takes time. It may be the day after your tensioning the 1/1250 may blank again therefore it is necessary to tension until the 1/1250 stops blanking again. Henry has said that he has had some cameras which will keep changing even 6 months later.
Another point made to me was that due to Leica's patents, Contax had a very hard time designing around the Leica-type shutter, this led to the creation of the vertical slat shutter observed in Contax cameras. The shutter functions differently from a Leica-type shutter as instead of passing the slit of light over the film plane the whole curtain assembly remains open the whole time of the exposure with the second curtain coming down like a blade to end the exposure. This design means many shutter testers can not read the speeds correctly. A good 1/1250 may actually come up as around 1/800 on a modern shutter tester.
The last bit of info I gleamed from Henry was that due to the complications of the adjustments cameras would come out of the factory with incorrect high shutter speeds.
I hope this information is helpful to anyone brave enough to delve into these cameras but I will pass one piece of advice I got from Henry: When you are working on a Contax if you don’t know exactly what you are doing and how to get out of it if it should go wrong then don’t do it.
kaptn_kapton
Newbie
Hello,
at first a big thanks to everyone who contributed to this amazing collection of knowledge! I am currently working on a IIIa, where the slow and medium speeds seen to work fine, but at high speeds and on B, T the curtains are running down without separating. The camera is open and and looks like in a quite good condition. Does anybody have some ideas?
at first a big thanks to everyone who contributed to this amazing collection of knowledge! I am currently working on a IIIa, where the slow and medium speeds seen to work fine, but at high speeds and on B, T the curtains are running down without separating. The camera is open and and looks like in a quite good condition. Does anybody have some ideas?
kaptn_kapton
Newbie
I found the problem: the high speed lever did not engage in the high speed couples one the 2nd cam shaft. Understanding the mechanisms helps... all information was already there 😀
MarcoIIIc
Member
Does anyone have a source for this shutter cord?
kaptn_kapton
Newbie
I don't know about any source. I think this is a silk cord, but I would probably try to replace it with a Kevlar nano cord like paracord has one. May compare the diameter first. I don't know if this works and how the stiffness compares to the original one, but what are the options...
MarcoIIIc
Member
It is a 0.5mm cord, silk maybe…. Someone suggested surgical silk suture (hard to find in the size I need) or braided fishing line… I have ordered some fishing line. Will update the thread after the testing.
lucky_analogue
Newbie
Just signed up here because I ran across this thread *after* doing full services to two IIa's and wish I had this info prior. I found out through trial and error the very counter intuitive fact that decreasing tension actually increases effective top speeds. Do you understand how? Because I certainly don't. It would be very helpful to understanding these weird designs.
Also, did Henry clarify why a modern tester would read the 1250 speed wrong? As far as I can tell, these do in fact work like normal modern shutters, in that they have a fixed high speed travel time and use variable slit width to make different effective speeds. Is that not actually correct? The full gate can't possibly be open for only 1/1250, the curtain speeds are way too slow. I was able to fix 1250 traveling closed by simply delaying second curtain open (i.e. enlarging the slit width) via the first curtain cam. Once that was done, that led down the rabbit hole of finding proper tension and finding that the camera's (very high) current tension setting was only yielding 1/300 at 1250 - something I noticed Henry mentions being a common problem with previously serviced cameras sent to him. What I can't understand is *why* significantly less tension actually sped it back up to 1/1000 on my tester - all while having no meaningfully negative impact on medium and low speeds.