This is a fantastic thread, thanks for posting all the detailed technical and background information Brett! It's particularly relevant for me as I recently added a beautiful IIIf to my Leica [insert word for a collection of 3 or more]. I rapidly went from 1 and 3/4 Leicas (an M2 and IIIg that I was restoring) to 4 Leicas: the final parts to reassemble the IIIg self timer arrived after a 12 month search; then the IIIf was offered to me, with 3.5 Elmar, for around AUD500, then I was lucky to find, in the same week as the IIIf, the cheap M4 I posted on another thread.
My IIIf has an issue that the second shutter curtain follows the first slowly, it takes a second or 2 to close the shutter, so perhaps the tension is wrong. In your opinion is that something fixable without needing the measurement equipment you have used? I'm interested to know whether this is something that can be fixed through simple adjustments (by me), or would require a proper overhaul (by someone experienced, perhaps someone in Tasmania...!).
Also, the Elmar helicoid grease was completely dry. I have removed most of it without disassembling the helicoid - it's much better now but in need of some new grease. Is there a particular helicoid grease recommended for Leica lenses?
Hi
I'm glad you're getting something out of the words and images, thank you for the feedback.
Just to clarify, with your IIIf, what you're saying is that the second curtain isn't just pausing before it caps off the film gate—it's basically creeping across the gate, slowly? Is that correct?
If the curtain was running normally, but not immediately, my first thoughts would be to investigate the second curtain latch in the event it's sticking. But the latch holds the curtain back until it's tripped. Once it's tripped the curtain will (all other things being equal) just run at its proper speed.
If the curtain is crawling across the gate at a snails pace, at face value two things come to mind.
A:
perhaps somebody has fiddled with the curtain tensions?
I have come across certain cameras with curtain springs that kark it with age. The Zeiss Icarex SLRs are a great example. But this is a IIIf, a much better quality design. So, unless some total numpty has over tensioned its spring to the point of permanently deforming (or even, perhaps, breaking) it—the only way it could have slowed so badly (if it's running free) must be, if it's badly adjusted?
B:
I mentioned "running free" above. Something that might, conceivably, slow a curtain down is a foreign object in the works. Film chips are the obvious suspect. I've pulled a few out of screw mount bodies. (Incidentally, this seems, to me to be a good reason to not be too ambitious about sneaking that 37th or 38th frame from a roll—the residue I've extracted was from a film gate was stripped perforations, no doubt due to forcing the wind knob for that extra frame).
There are, of course, other unpleasant scenarios that might make a curtain hang up. A detached ribbon fouling the works is an obvious one. But you'd have a curtain misaligned and moving unevenly top/bottom were this to be the case.
Similarly, if a curtain has aged really badly (storage conditions may be germane) and its lightproof coating has become very stiff, it could retard the speed (being less willing to unspool, and possibly, so inflexible as to foul the inside of the gate, for instance). I've got a pre-war Kine Exakta here with a bit of that going on. To its credit, its shutter gamely tries to do its thing. But the fabric is more akin to thin cardboard than flexible fabric, now (Exaktas in general, as charming as they are unusual, aren't exactly known for being fitted with curtains which age gracefully, so this is not news).
But we can safely discount both these reasons. If a curtain wasn't securely attached at both ends, you'd see misalignment where the laths of each curtain meet. And I've never seen anything to the effect that Leica curtains are worse quality than most—except, perhaps, some wartime red fabric examples, of course. The curtains being that badly deteriorated is extremely unlikely, and if they were—you'd be able to tell.
So, there is quite a laundry list above, of different types of ailments which might virtually stop a curtain in its tracks. But as discussed, for various reasons, we can probably discount most of them. Tampering with the adjustment, or foreign object interference, would seem to me the most likely scenarios, yes?
In terms of making things right: the mechanism will be coming out of its casing (or housing, if you prefer). I'd suggest you'd have to be very lucky, but it's just possible, I suppose, that removing a jam might see it happy again.
Realistically, though, these are not young cameras any more. If, for instance, a previous owner upset the curtain adjustment, this will have been because the shutter wasn't 100% in the first place. So even if you were able to get the curtain closer to proper speed, it's odds on the shutter won't, then, be running at its best anyway. Cleaning and lubrication is very likely needed, and, because of age, the curtains may manifest some pinholes. But, my friend's IIIf passed a pinhole check with flying colours and its curtains are still supple. So, whereas curtain replacement isn't a fait accompli, it is, however a distinct possibility after 50+ years.
To accurately set focal plane shutter times correctly, a test device sophisticated enough to accurately read effective exposure in at least the opening and closing portions of the film gate is a huge assist. My Kyoritsu sensor can read the times at the start, centre and end of the curtain run. (Getting it years ago was a major score since it had been lightly used prior to coming into my hands, and with little interest in film equipment before the renaissance we're experiencing now, I was gifted it at no cost.)
Prior to acquiring it however I had adjusted many focal plane shutters using nothing more than an old cathode ray tube television receiver. If this seems a low tech approach, revisit some of the detail in my first post—specifically, the page from the Leitz IIIf service manual and my associated comments—and then consider that Leitz themselves originally calibrated these cameras using equipment not very much more sophisticated.
One of the better summaries of how a CRT set can be used to check speeds can be found at Rick Oleson's site:
http://rick_oleson.tripod.com/index-135.html
The biggest drawback with this idea, is that the degree of accuracy possible depends largely on the experience of the person checking a shutter. Speaking from my own experience. Sure—if you have never tried this before, after five minutes, you'll certainly have a broad brush idea of how well a shutter works. But getting the best results hinges on a trained eye—more correctly—a trained brain. You can get a good indication of the relationship between the curtains by the overall shape of the slit, its acceleration by the change of slit angle across the gate, and consistency of exposure by the relative width of a slit across the whole gate. But the slit is only visible very briefly, hence, considerable concentration is needed to observe the slits, remember their width, and interpret what a particular speed is doing, overall. In short: the more experience you have with it, the more precise—within limits—you'll be. Can it ever be as precise as a three digit digital tester set up? No, of course not. It's not as quick to use, either. That said: I've got very satisfactory exposures on Fujichrome, using shutters I've corrected with a CRT. So (with a bit of practice and experience) it can be quite a viable way to get reasonable results, and it's a darned sight better than photographing spinning turntables IMHO. I keep a small CRT set on the shelf next to my Kyoritsu. It's rarely used these days but occasionally, when setting a shutter up from zero tensions, it can actually be quicker and easier, initially, to get it in the ballpark visually before switching on the tester to optimise the times. But my Kyoritsu, whilst in excellent repair, is a 1970s model that doesn't provide curtain travel times. If it did, I'd only use the CRT very rarely, indeed.
I used Helimax XP optical grease ex-eBay for my Summarit. Eg:
https://www.ebay.com/itm/271211561097
Whether it's the ideal lubricant for Leitz threads, I don't know. I found it OK though, the lens is smooth to adjust without being too stiff. Most German manufacturers would have used (still use) special optical grease from German specialist Losimol, who have been in the trade many decades. When new, a particular Losoid formulation would have been applied by Leitz. Losimol are still in business, but definitely not geared to supporting small scale or hobbyist users. They'll sell you all manner of wonderful, tailor made formulations for optical/photographic applications on request: if Eg you can afford $1000 for a one kilogram container. Yes—I've spoken with them, and that was the quote!
For quantities of special purpose lubricants that are more sane for occasional users, Japan Hobby Tool do list several different viscosities of optical grease. See here:
https://www.ebay.com/sch/m.html?_ss...ksid=p2046732.m570.l1313&_nkw=grease&_sacat=0
And Micro-Tools list (used to list?) certain types as well.
https://www.micro-tools.com
I've got yet another IIIf and a IIIc coming to me in next couple of weeks, so it seems I will be getting a bit more practice in getting screw mount Leicas working again. If you think getting the IIIf going may be problematic for you, you can message me and we can see what we can work out.
😉
Cheers,
Brett
