Elmarit M 28mm (iii)

[seneschal]

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I recently acquired a 2nd user. 28mm Elmarit M and have been shooting just to try it out on my M9.

The lens‘s aperture ring was loose, moved fore and aft, and was also misaligned with the index by one stop, such that, at full aperture, it was indicating f4 instead of f2.8 and similarly was past the f22 inscription when closed down.

All click stops were working snd the lens was focusing correctly with the rangefinder.

I was pretty pleased with the little thing and decided to get it repaired, but after phoning my local repair shop, it was going to be a month before they could look at it.

SO I DECIDED TO HAVE A LOOK MYSELF.

I unscrewed the lens from the focus mount and discovered that it was simply a split retaining ring which seemed to have jumped out of its groove on the lens barrel, allowing the aperture ring to move back and forth.

Having replaced the retaining ring and screwed the lens back into the focus mount, realigned the ring and index marks I have put the lens back on the camera really pleased with myself to take some test shots.

The lens is no longer focussing correctly.

I am completely at a loss as to what I have done wrong. It was working perfectly, just with a loose and misaligned aperture ring.

Now I can focus the rangefinder, check the reading on the focus mount distance scale and it seems to be correct. The focus ring moves easily and smoothly, as it did before, from infinity to just below 0.7m.

The shot, however, when viewed is a mile out.

It’s almost as if the lens head is now screwed too far into the focus mount.

Is this possible? Surely the lens head screws into the focus mount in just the same way you would do it with a LTM lens?

Any ideas what I am missing please? I am stumped for now.... all advice (other than take it to the repair shop and be more patient) will be very gratefully received.

Thanks so much for your help in advance.

 

[capo di tutti capi]

I'm surprised. The factory uses a laser to check that each lens is installed correctly. I try not to buy used items. 

Edited May 26, 2021 by capo di tutti capi

[rcusick]

Leica cla and 6 bit coding will be $700 .   Expensive but they do quality work.  

[seneschal]

I am wondering if there is anyone with some degree of technical competence who might be able to diagnose or suggest a diagnosis for what is going on. I am pretty confused as to why I could previously focus on my M9 using the rangefinder and the photos taken would be in focus, i.e. the lens was properly calibrated with the rangefinder.

All I have done is taken the lens body out of the focusing mount, replaced the aperture retaining split ring where it should have been and screwed the lens body back into the focusing mount. The result is that the lens is no longer properly calibrated against the camera rangefinder. My other M lenses still focus correctly, on this rangefinder, I tried this in case I had unwittingly done something to the M9... but I have removed that possibility.

So, it is as if the lens body was not fully screwed in to the focusing mount previously before I did the aperture ring repair. Now, I can imagine that the loose split ring could have been preventing the lens body from screwing into the mount fully, but then why would the lens have been focusing correctly.... pure coincidence maybe, or perhaps it was set up to focus when displaced from its proper position? Should there be a "spacer" between the lens and the mount, I can't imagine why this would be the case, but it would move the lens body forward in the focusing mount, away from the film plane.

Just to make things even weirder, I have mounted the lens on my OMD E-M1 and experimented with the focus on there, to get a better view of what is actually happening. The result is that the lens is currently focused on infinity (or at least clouds in the sky... maybe 2-3000 metres) when the lens is at the close focus point (sub 0.7m), which is the point where the helicoids have moved the lens furthest from the film plane. So what is effectively happening is the lens is focused on infinity at the closest focus point on the scale but is then focusing past infinity when the helicoid is closed, bringing the lens body closer to the film plane.

Does this help diagnose? There is nothing in the smooth movement of the helicoids that suggests it was disassembled and put together incorrectly in the past, but it is clear to me that the lens body is too close to the film plane since I put it back together again and was not too close previously.

Anybody got any ideas on what is going on? It's clearly not a problem from the factory, how could it be, no surprise there at all, it is a third generation 28mm Elmarit, not a current 28mm Elmarit ASPH, it is a used lens with known provenance from the estate of someone closely attached to design and the art of photography. Yes, I could send the lens to a Leica specialist repair shop or even Leica themselves, but it was the necessary wait and my impatience that tempted me to repair the aperture ring myself in the first place.

I am interested in understanding what is going on, if anyone who is technically competent can make any useful suggestions? Please? I do not need to be told that a repair shop could fix it, I already know that. What I don't know is why the lens is now exhibiting this strange and rather particular behaviour. That is what is interesting and worthy of understanding. Anybody got a parts diagram for a third gen Elmarit 28mm?

[pedaes]

You took lens apart and created a problem. Go back over what you did.

Most here would leave it to experts.

Edited May 27, 2021 by pedaes

[capo di tutti capi]

1 hour ago, seneschal said:

I am wondering if there is anyone with some degree of technical competence who might be able to diagnose or suggest a diagnosis for what is going on. I am pretty confused as to why I could previously focus on my M9 using the rangefinder and the photos taken would be in focus, i.e. the lens was properly calibrated with the rangefinder.

All I have done is taken the lens body out of the focusing mount, replaced the aperture retaining split ring where it should have been and screwed the lens body back into the focusing mount. The result is that the lens is no longer properly calibrated against the camera rangefinder. My other M lenses still focus correctly, on this rangefinder, I tried this in case I had unwittingly done something to the M9... but I have removed that possibility.

So, it is as if the lens body was not fully screwed in to the focusing mount previously before I did the aperture ring repair. Now, I can imagine that the loose split ring could have been preventing the lens body from screwing into the mount fully, but then why would the lens have been focusing correctly.... pure coincidence maybe, or perhaps it was set up to focus when displaced from its proper position? Should there be a "spacer" between the lens and the mount, I can't imagine why this would be the case, but it would move the lens body forward in the focusing mount, away from the film plane.

Just to make things even weirder, I have mounted the lens on my OMD E-M1 and experimented with the focus on there, to get a better view of what is actually happening. The result is that the lens is currently focused on infinity (or at least clouds in the sky... maybe 2-3000 metres) when the lens is at the close focus point (sub 0.7m), which is the point where the helicoids have moved the lens furthest from the film plane. So what is effectively happening is the lens is focused on infinity at the closest focus point on the scale but is then focusing past infinity when the helicoid is closed, bringing the lens body closer to the film plane.

Does this help diagnose? There is nothing in the smooth movement of the helicoids that suggests it was disassembled and put together incorrectly in the past, but it is clear to me that the lens body is too close to the film plane since I put it back together again and was not too close previously.

Anybody got any ideas on what is going on? It's clearly not a problem from the factory, how could it be, no surprise there at all, it is a third generation 28mm Elmarit, not a current 28mm Elmarit ASPH, it is a used lens with known provenance from the estate of someone closely attached to design and the art of photography. Yes, I could send the lens to a Leica specialist repair shop or even Leica themselves, but it was the necessary wait and my impatience that tempted me to repair the aperture ring myself in the first place.

I am interested in understanding what is going on, if anyone who is technically competent can make any useful suggestions? Please? I do not need to be told that a repair shop could fix it, I already know that. What I don't know is why the lens is now exhibiting this strange and rather particular behaviour. That is what is interesting and worthy of understanding. Anybody got a parts diagram for a third gen Elmarit 28mm?

There are usually several starting points. To start the carving. You started to twist in the wrong carving. Before unwinding it was necessary to mark with a pencil. So that later it will coincide 

Edited May 27, 2021 by capo di tutti capi

[seneschal]

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Mmm, advising me to go back over what I did. Mmm, hadn't thought of that. I have dismantled and re-built many lenses, clocks, watches, gearboxes, car engines over the years... I am not afraid of engineering and not so mentally challenged that I feel the need to always leave it to the experts. I am looking for some technical advice, from someone who is an expert. Eventually, I will work out for myself what is going on, all I am doing is trying to shortcut my process of learning. If we do not challenge ourselves every day then how do we learn? I am sure that you are right, "most here" would leave it to the experts.

It's just about mindset... and I get it, some people are not interested to know how things work, and could not understand even if they applied their mind to it, but I am. I remember a friend of mine in Zürich telling me a story one day down by the Zürichsee, he'd been talking with his neighbour about how he'd been having trouble with the remote control for his Tiefgarage over a couple of days and so decided to replace the battery in the handset. His neighbour was horrified... "what?? you replaced the battery?? yourself?? what do you know about remote controls or garage doors or batteries?? who knows what damage you could have done?? it's people like you who are putting the garage door repair man out of business"

It's all just a matter of scale, we are all at different levels of technical competence and understanding, my degree was in Mathematical Physics so I am naturally inquisitive, where would we be if Einstein had not mused about travelling on a light beam? "most here" probably would not waste their energies on such musings, far better to muse on which aspherical masterpiece to buy next... CLA, heaven forbid... leave it in a drawer and buy a new one... it's obsolete anyway.

So, I enjoy tinkering with things, I enjoy fixing stuff and I enjoy the process of learning how to do it, it gives me a feeling of success, satisfaction and achievement when I finally complete a job... each to his own. I will happily change the brake pads on my 911 Turbo, but I would not rebuild the turbochargers... special equipment and expertise needed, nor would I just buy a new car!

I will happily dismantle a lens head from a focusing mount to  fix an aperture ring but would not dream of dismantling the lens head itself... I am pretty wary of taking the focus mount to pieces to see if the helicoids are not actually assembled correctly...

Anyway, please... if there is any expertise out there, I will be happy to receive proper considered technical advice rather than vacuous statements of the obvious.

[capo di tutti capi]

I also like to disassemble. Last time my front and back lenses cracked. They are very thin. I have no desire to repeat this experience. Good luck! 

[AndreasG]

According to my knowledge the focussing thread has a multiple lead - double or even triple. Most probably you simply caught the wrong thread "entrance" upon assembly, resulting in the malfunction of focussing. Simply disassemble again and try out the various leads until you succeed.

[seneschal]

Point in hand, our cleaner just told me that the Dyson's stopped working.... do I call out a repair man? do I buy a new Dyson? do I sack the cleaner?

No, I go through a process of elimination and discover that there is a blockage in a pipe from the rotating brush head, under the motor assembly running up to the cyclones... it's a bit difficult to find, but there it is. Removing the detritus of my second daughter's pencil shavings and other waste from he arts and crafts activities with a quickly fashioned tool made from an old coat hanger means the Dyson is reassembled in less than ten minutes and works like new again.

A similar process will lead me to discover why the lens is now too close to the sensor/film plane.

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[AndreasG]

vor 3 Minuten schrieb seneschal:

A similar process will lead me to discover why the lens is now too close to the sensor/film plane.

Just follow #6 and 9#.

[seneschal]

I have not dismantled the focusing helicoid at all... I just took the lens body out of the focus mount. The helicoids are all intact... but I do suspect that someone has previously had it apart and perhaps put it together wrongly... but, if they did that, then I do not understand why they didn't fix the aperture ring. Maybe they accidentally dismantled the helicoids when they were attempting to fix the aperture ring and discovered that's not how you do it... and then gave up?

That would explain things possibly, they never discovered how to repair the aperture ring after reassembling the helicoids wrongly.

And.. bizarre coincidence... the wrongly assembled helicoids meant that the lens body not being fully assembled into the focusing mount was somehow strangely in focus with the rangefinder...

Nightmare!

 

[pedaes]

1 hour ago, seneschal said:

Mmm, advising me to go back over what I did. Mmm, hadn't thought of that

Love your attitude. You have buggered it, end of.

[Gobert]

1 hour ago, seneschal said:

I have not dismantled the focusing helicoid at all... I just took the lens body out of the focus mount. The helicoids are all intact... but I do suspect that someone has previously had it apart and perhaps put it together wrongly... but, if they did that, then I do not understand why they didn't fix the aperture ring. Maybe they accidentally dismantled the helicoids when they were attempting to fix the aperture ring and discovered that's not how you do it... and then gave up?

That would explain things possibly, they never discovered how to repair the aperture ring after reassembling the helicoids wrongly.

And.. bizarre coincidence... the wrongly assembled helicoids meant that the lens body not being fully assembled into the focusing mount was somehow strangely in focus with the rangefinder...

Nightmare!

 

It is not a nightmare, it is an opportunity to learn more about your lens.

[seneschal]

39 minutes ago, Gobert said:

It is not a nightmare, it is an opportunity to learn more about your lens.

OK, man up... I say to myself, double helicoids one operating the rangefinder focus cam, I know that is right because the rangefinder and distance scale match for the subject when locked in to focus in the rangefinder patch. I need that to go back where it is now.

Second helicoid carries the thread for the lens body as it mounts into the focusing mechanism. I know this is in the wrong position because the lens is focused on infinity when the distance scale is on 0.7m. So that helicoid needs to be further forward.

I am not comfortable with this but @AndreasG has tempted me to try (you are a braver man than me) and @Gobert has reinforced my learning Mantra. @pedaes, I haven’t buggered it yet, but I am probably about to!

PH00 at the ready....

 

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[luigi bertolotti]

Can you post a pic of the removed lenshead, with its thread well visible ? 

And... a silly question... when remounted, is the lenshead correctly positioned in angular terms ? (In the Elmarit III, seems to me that the f stop index is aligned with the focus index on the focusing mount... but don't know by sure if it's exactly like this)

Years ago have a similar problem with a Summaron 35... it arrived in my hands with correct RF coupling and total misfocus (in the same sense as yours... "too much inside").... it was easily (and free) adjusted by the seller... but dunno how he did...

 

 

Edited May 27, 2021 by luigi bertolotti

[AndreasG]

vor einer Stunde schrieb luigi bertolotti:

(In the Elmarit III, seems to me that the f stop index is aligned with the focus index on the focusing mount... but don't know by sure if it's exactly like this)

This is correct, see the photo:

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[fotografr]

My advice is to email Don Goldberg with your question and photos. He's one of the world's best when it comes to fixing Leica lenses.

dagcam@chorus.net

 

 

[seneschal]

12 hours ago, fotografr said:

My advice is to email Don Goldberg with your question and photos. He's one of the world's best when it comes to fixing Leica lenses.

dagcam@chorus.net

 

 

OK, that‘s a very helpful piece of advice @fotografrI will do that.

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[seneschal]

@luigi bertolotti and @AndreasG Thanks, for the questions and picture... I had already checked various photos on the internet for that particular alignment. You are right, that is exactly how it should look. It is really easy to achieve the alignment once the lens body is in the correct place in the focusing mount. There are three grub screws in the Aperture ring which clamp the ring against the diaphragm operating ring inside the barrel. Set the lens to maximum aperture and once you have loosened the screws you can rotate the ring to align the correct number along the axis that includes the focus mark.

Similarly the bezel on the front has three smaller set screws which clamp the bezel to the barrel, these can also be loosened to rotate the bezel to align with the same axis, this position is more critical... whilst you can easily still read the aperture if you were a couple of degrees out, with the bezel it needs to be correct or the rectangular lens hood does not align parallel with the base and top plate of the camera (and therefore the sensor or film plane) if it is not quite right. I doubt it is noticeable on the photos, or causes any kind of vignetting unless it is a mile out, but it is irritating to see when the hood is just that tiny bit not straight!

I now know exactly how this lens operates, once you get inside the helicoids, three screws on the mount for the lens body and six screws underneath on the bayonet. It can only go together in a particular configuration. Since I was happy with the rangefinder helicoid I ensured that did not move and just changed the lens mount helicoid. I made the assumption that it had not been completely unscrewed, and perhaps put together wrongly with the incorrect start points, but maybe had been accidentally rotated. Because of the configuration of the helicoids, it can only be reassembled in one way, there are two guide tabs and grooves on one side and one guide tab and groove on the other side, these ensure that the helicoids move in synchronisation, one focusing the lens, the other operating the rangefinder cam.

The focusing helicoid can, therefore only be rotated by 180 degrees until the tabs align again if it will be able to go back together. I tried it two half turns out... and turned the lens into an interesting close focus macro lens!! Obviously wrong.

I then tried half a turn in and could not achieve minimum focus, the helicoid will not achieve two full half turns in.

All of the testing was completed initially on a Pen E-PL5 rather than the OMD E-M1.

So, it was clear that the helicoids needed to be back the way I had found them, no issue at all with those and the focusing mount could be put back together.

The next step was to find where the lens body should be in the focusing mount itself. If I screw it all the way in to the mount it is too close and therefore focusing past infinity. By adjusting initially against measured distance objects on the Pen I could get it there or thereabouts. The lens is not screwed all the way in to the mount.

I then moved on to the M9 and degree by degree moved the lens body, focus using the rangefinder, took a shot, inspected and repeated until I was satisfied that I was getting sharp results, close focus, infinity and intermediate distances.

It is now working perfectly, spot on... but the big "but" is that the lens body is not screwed into the focusing mount as far as it can be screwed. Something must be in place from the factory that stops the lens from being screwed all the way in but allows the build and test adjustments to be made to get the lens perfectly synchronised with the standard rangefinder.

There is no sign of any Loctite or other thread treatment, so I am convinced that there is a spacer, or shim of some kind missing.

Anybody know? Anybody fancy unscrewing theirs and telling me if there is a spacer (don't do this!) I now know the helicoids work and focus properly, the lens body itself is in immaculate condition and produces beautiful images for something from the late '70s/early '80s.

I am delighted, learned a lot, not buggered it up thankfully... but I still need to know how the lens body is supposed to be secured in the focusing mount safely and securely.

I will unscrew the lens again, take a picture as @luigi bertolottirequested, but maybe tomorrow in bright daylight and outside when I can perhaps fine tune it even further... I'll use some tape to mark up and make sure I don't completely lose my hard won progress from today.