Pre-war Fed lens registration -- again

[rfaspen]

I know this subject is often discussed. I'm hoping to hear from people who have actually done something about it -- experiences.

I recently bought a pre-war Fed 1 (looks to be early 1d to me) from someone here on RFF (thanks David!). Its a very nice example -- nicer than I thought it would be. I should say I really like *both* Leica and FSU gear very much. I don't make serious comparisons between them because each has its own qualities. The pre-war Fed 1 bodies are really very nice (as most of us know) and I prefer to actually use my gear and not let it sit on a shelf.

So, I checked the film-to-flange distance on this Fed and I get about 25.5mm. Somewhere in the swirling, confusing, literature and lore about early FSU, I read that some really early stuff was made with 25.5mm filmtoflange distance. Well, OK. I'm not trying to solicit a discussion of when, where, why the 25.5mm distance. I'm aware that Fed 1d is kind of "late" for pre-war bodies and that they may have been attempting 28.8mm by then. All I know is my measuring instruments are pretty reliable, accurate, and precise.

Now, if I'm to use this body with my selection of post-war FSU, Leica, Japanese, etc. LTM lenses, I need to do something about the film to flange distance. Shim? Seems to be the prevailing approach. I'm also aware that the current lens mount ring has a different start point making the "fix" a bit more challenging. It has been mentioned elsewhere on this forum that if I rotate my lens mount 90 degrees to address lens resting position, I would have to mill a new flat on the backside at top to make clearance for the rangefinder arm. More on that in a minute...

I'd love to hear experiences from anyone who has dealt with this. First off, the difference between 25.5 and 28.8mm is 3.3mm. That's quite a lot! So, if I'm thinking clearly, I'm looking at finding a lens mount ring from a post-war body (e.g., Fed2), determining its thickness because it will likely be different than the original mount ring on the camera now, then place something like 3.3mm of shim material between mount ring and body casing (actual amount of shim determined by thickness of Fed 2 mount ring). This just seems like a lot of shim. Could this be right? If so, I think I could drop the need for the Fed 2 mount ring because I could easily incorporate clearance for the rangefinder arm in 3+mm of shim!

Sorry if this topic (shimming for leica standard) has been beaten to death. I just didn't see anything conclusive in my searches, and I'd dearly love to hear firsthand experiences. I'm certain there's more to this idea than I think.

Thanks!

 

[wolves3012]

Here's my understanding of it. It's based partly on what I've read as "fact", partly on what I've read as opinion and partly on personal experience. In other words, don't treat it as gospel. Others may shed more light or correct me. Also, remember there were a few changes along the way plus the notorious QC (or lack of) issues, just to throw in a few more variables!

Pre-war FEDs were made to no particular flange-to-film spec, or not an accurate one anyway. Each lens was matched to the body it came with, at the factory. Therefore, it was more theory than practice that said it had interchangeable lenses. Additional lenses had to be adjusted to suit the body. The lens-mount also had a different pitch thread than the "standard" Leica-thread. Given some wear in the threads, later lenses may or may not thread properly, or at all. Later mounts are not noticeably thicker (AFAIK) so fitting a later mount doesn't solve the flange-to-film distance issue. Adding a thick shim also messes up the RF and that may well not be within its range of adjustment with such a shim. In fact, I'm pretty certain that a 3mm+ shim will make the RF useless. As it happens, my 1939 NKVD was set as 27.8mm but the thread won't take most later lenses so it's academic anyway.

The mount threads are not cut with a specific entry point either, there's quite a variation where the lenses "park" but again, it's not the same as later mounts anyway (well, often not). Rotating a mount and milling the flat isn't for the faint-hearted, that would need to be very accurate indeed and parallel. The flat mates with the body, so you'd also end up with a gap where half of the old flat remained, which would weaken the mount and risk distorting it when fitting the screws/retaining plates. I don't know if anyone has done this, I suspect not with any great success.

The long and the short of it, it's a bit of a jumble of things to sort out if you really must use other, later lenses without modifying them and hence quite a headache to achieve. It's better to view it as a fixed-lens setup and live with that. Sorry to pour cold water on the idea. It's not that it's impossible, it's just that you need to see the grief first!

 

[agfa100]

I only have one Fed prewar lens, it's a 100mm f6.3. With a ltm to M adp it will focus on M film cameras OK and it worked when I tried it on a M Monochom it seemed to work ok...I shot a couple of pic's on a friends M-6 and he was impressed with the results.... So I wonder if it's dof may make up the difference in the flange issue? Just a idea, I use it on a Ricoh GXR so I don't worry about flange issues. I was lucky to find a Russian a36 lens hood as it flares easily.

 

[rfaspen]

I forgot to mention, I don't own any pre-war FSU lenses. I don't think I own any pre-war LTM lenses of any kind. Well, actually my Summar is supposed to be 1933. But that's the only one 🙁

I'm aware of thread difference between Leica and FSU. It's never been an issue with any of my lenses and bodies. A couple of "tight fits" but nothing to stop me. I tried a number of lenses on the "new" Fed 1 and they all mount fully, even if the infinity stop ends up in the "wrong" position. Usually about 6 o clock.

I'm not worried about the history of FSU gear, or the desire to achieve a standard or not. I'm hoping to find firsthand experience with attempting to use regular LTM lenses on a body that isn't to spec for them.

I think 3mm is quite a lot to shim. But, if folks out there have successfully done that, I'd like to hear about it. I mean, it seems possible, but until one tries, it remains a big unknown. I did wonder about the RF and 3mm of shimming. There are ways of managing that, but it adds to the "effort".

I don't own any pre-war lenses to dedicate to this body, so my desire is to make LTM work with it because I'm not into "shelf queens". But, if its not feasible I guess I'll look for an opportune pre-war lens. Its not a priority.

Thanks. I sure hope someone out there has a specific experience to share.

 

[wolves3012]

If you decide to go ahead and attempt to modify it, I'll be interested to know how you solved the issues and I'm sure others would too...please let us know how you get on.

 

[johannielscom]

I've never read about anyone covering 3.3mms with shims on a prewar FED and am amazed about it even being possible, regarding the RF issue.

Can you share a link?

Getting the body and lens combo to agree fully on a prewar FED Komandirski I once owned was done by Fedka.com, Yuri's repairman set it straight and it was spot on after that. As I understood, Fedka.com nowadays send repairs out to Russia, since their repairman either retired or died.

Getting the body and the current (or extra) lens to agree 100% certainly can be done, but unlikely that this will be at Leica specs! YMMV.

 

[Penny Lane]

3.3 millimeters difference is a HUGE gap to bridge. Normally when you're within spec, there's a +/- 0.02mm tolerance...

My own pre-war FED came out at 28.5 millimeters or thereabouts, based on the pre-war lens that was sold to me on a post-war Zorki (which combo didn't work well at all). I shimmed the FED body to match the lens, which was a hassle but worth it in the end.

IIRC the early film-to-flange distance should be around 28.5 millimeters (ish), corroborated by my experience with my own FED-1 where I had a lens to check the register depth from. I had tried to bridge the .3mm gap to 28.8 and that was pretty easily done, but I decided to set the body to match the pre-war FED lens and call it a fixed combination.

At 25.5mm we're talking about a pretty major design revision, and a difference that's 3 times or more the thickness of the vulcanite body covering which tells you there's something really off. I hope that the 25.5mm was simply a typo...

Derk

 

[rfaspen]

As a woodworker, I know that we measure twice before performing any operation. I thought 25.5mm was wrong as well, but measured twice. Also measured a couple of my Leicas, a Zorki and a Fed 3 using the same instrument and method. Those all came out close enough to 28.8 for me.

I completely agree that 3+mm is huge. I just can't imagine that much shimming which is why I figured I'd ask around to see if anyone has really done such a thing.

I'm going to measure my film to flange distance again later today. Who knows, something may have been odd about the other day and now the stars and planets have aligned to make good measurements again.

I've been mulling over the situation with this Fed, and probably won't attempt 3+mm shimming unless I hear from someone who has successfully done it. If I have to, I don't mind keeping an eye out for a pre-war lens, although it still might require some effort to get that fixed combination right. This little Fed really is a nice little camera; A "Kombinat" in good condition and the shutter appears to agree with nominal speeds. In all, its ready to go out shooting, just needs a lens.

BTW, its really unfortunate that Yuri's repair services have ended. There remains a genuine need (market) for competent FSU work in the U.S. I do think that one of the competent shops should invest in whatever needed to offer FSU services. An FSU-only shop would result in someone starving, but FSU services as part of a suite of repair capabilities at a larger comprehensive repair shop, I think that would pay off.

Thanks everyone for your comments.

 

[Ron (Netherlands)]

Just to give some food for ideas...
Once I had a Zorki 6 that wouldn't focus at close distance. A shim couldn't work since the flange - film plane distance was already too long. Taking some additional test revealed the the camera had a wrong lens mount installed: it seemed to be the lens mount of an early Zorki 3C or Zorki 4 that is a bit ticker than the original Z6 and Z5 mounts, so changing the mount made the Z6 focussing again correctly.

 

[David Hughes]

Hi,

3+ mm would throw out the rest of the body in several ways so I'm hoping we can get to the bottom of this and I can sleep at nights again...

Regards, David

 

[rfaspen]

Ummm,

OK, here's what happened. Aliens landed in my neighbors yard and started eating the landscaping and I was just too distracted while making a delicate measurement... It could happen to anybody...

Today the film to flange is 27.8mm. I did something wrong.:bang:

Many many thanks to everyone who aren't laughing now.

My guess is I can use that Fed2 mount now or just get a pre-war lens. Either way, nothing out of the ordinary here😀

 

[outfitter]

Measuring the flange to film plane distance is tricky as the film plate is on springs - don't think I've ever had a reading I felt confident with. Additionally the threads on the pre-war Feds are at a different pitch than post-war, but most - but not all - can the screwed on. I have taken a turn the ladder rather than turn the light bulb approach. I took the many pre-war lenses I have, picked the best looking pre-war body and took photos of a sign outdoors from a tripod (keeping good notes). Crude but effective as I was able to find body lens matches without shims etc.

 

[wolves3012]

Ummm,

OK, here's what happened. Aliens landed in my neighbors yard and started eating the landscaping and I was just too distracted while making a delicate measurement... It could happen to anybody...

Today the film to flange is 27.8mm. I did something wrong.:bang:

Many many thanks to everyone who aren't laughing now.

My guess is I can use that Fed2 mount now or just get a pre-war lens. Either way, nothing out of the ordinary here😀

Interesting result since it's exactly the same as my NKVD.

 

[rfaspen]

Wolves, yeah I just went back through the thread and noticed that you mentioned your NKVD is 27.8mm. I suppose mine would actually round up to 27.9 but I consider the precision of the indicator and the inevitable flex of the pressure plate. I guess I'm lucky because I've been able to mount most any lens I attempt so far. Aside from FSU stuff, a Canon 50/1.8 and a CV 21/4 went on without much resistance. I'll try others when I get a chance.

Anyway, I'm much happier to realize I'm not looking at 3+mm. That just wasn't sitting right, for several reasons.

 

[David Hughes]

I can sleep at night again...

Seriously, I was worried as I often use early FED lenses (like the f/2 Summar clone) on M series cameras and haven't started worrying about them.

Regards, David

PS Those aliens must have taken over from "the cat must have done it" as the all time, all purpose answer.