Traut
Well-known
I tried mounting my Nokton 1.1 on a few bodies and it will not click on. It feels like a hard stop after matching the dot and begin to turn. Any ideas?
35photo
Well-known
On what camera exactly?
mdarnton
Well-known
Is one of the screws on the face of the mount loose and hanging out a bit?
peterm1
Veteran
The first thing I would be checking is, as a poster mentioned above, the screws on the mounting flange to make sure they are fully seated. This is a simple thing to check hence do this first.
The second thing I would check are the lugs on the mounting flange of the lens (the four protruding metal bits around the mounting base that engage with the corresponding slots on the camera mount). I happen to have my Voigtlander f1.1 sitting in front of me at this moment and can confirm that on the Voigtlander Nokton (in fact on all M mount lenses, I suspect having had a quick look at a couple of others) these are quite thin and fragile looking and it would not take too much of a clumsy bump (such as if placed or dropped base down onto a hard surface too hard without the lens base cap being in place) to cause one of these to bend inwards / downwards slightly. This bend could easily misalign one of the lens' mounting lugs enough to prevent that lug from seating below the corresponding projections on the camera's lens mount and this in turn would be likely to impede rotation of the whole lens to lock it in place. Engineering tolerances are very tight for these lugs so as to make sure that lenses do not move or wobble when mounted and that proper tolerances are maintained for focusing. Hence any misalignment of only a few thousandths of an inch can prevent proper mounting. This may not even be visible to the naked eye unless accompanied by a dent or ding.
This is only a hypothesis in that I have not had this happen to me with a lens BUT I certainly have had more than one lens adapter of ostensibly good quality come to me fresh from the factory which would not mount on the relevant camera because it was out of tolerance. Only recently for example, I had to return one (a Konica to Leica M adapter) I purchased on eBay for this reason - it simply would not rotate and mount on any M mount camera. But the replacement one they then sent me (and previous ones I had purchased from the same maker) fitted perfectly. No deformation was visible on the faulty one and the lens mount flanges all looked perfect so it is clear to me that it does not take much of a misalignment to cause this problem. Like yours mine would not even begin to rotate into locked position. For some reason during manufacture something was slightly out of whack and never picked up by QA processes.
If there are no obvious dents or dings in any of these lugs - which if present might suggest a drop onto a hard surface), one way to check further is to try a "color transfer" method. Use a thick black felt tipped pen to color the parts of the lens mount that must engage with the camera's lens mount using the felt pen. Then try mounting the lens again and check to see if there are any obvious rub marks where color has transferred from the lens to the camera's lens mount in a place which suggests it may be binding at that point. This will at least help diagnose the problem. Alternatively, if you have access to a micrometer or vernier gauge / caliper check the lugs to see if any of them are misaligned from the others. Both of these techniques are legitimate techniques used by mechanical engineers when fitting metal parts to other metal parts.
If you identify an obvious issue after doing this, come back to this thread and we can discuss options for repair. BTW felt tipped pen is ideal for this because it is thin and adds nothing to the dimensions of the lens mount and because it can be removed easily and completely with alcohol etc.
The second thing I would check are the lugs on the mounting flange of the lens (the four protruding metal bits around the mounting base that engage with the corresponding slots on the camera mount). I happen to have my Voigtlander f1.1 sitting in front of me at this moment and can confirm that on the Voigtlander Nokton (in fact on all M mount lenses, I suspect having had a quick look at a couple of others) these are quite thin and fragile looking and it would not take too much of a clumsy bump (such as if placed or dropped base down onto a hard surface too hard without the lens base cap being in place) to cause one of these to bend inwards / downwards slightly. This bend could easily misalign one of the lens' mounting lugs enough to prevent that lug from seating below the corresponding projections on the camera's lens mount and this in turn would be likely to impede rotation of the whole lens to lock it in place. Engineering tolerances are very tight for these lugs so as to make sure that lenses do not move or wobble when mounted and that proper tolerances are maintained for focusing. Hence any misalignment of only a few thousandths of an inch can prevent proper mounting. This may not even be visible to the naked eye unless accompanied by a dent or ding.
This is only a hypothesis in that I have not had this happen to me with a lens BUT I certainly have had more than one lens adapter of ostensibly good quality come to me fresh from the factory which would not mount on the relevant camera because it was out of tolerance. Only recently for example, I had to return one (a Konica to Leica M adapter) I purchased on eBay for this reason - it simply would not rotate and mount on any M mount camera. But the replacement one they then sent me (and previous ones I had purchased from the same maker) fitted perfectly. No deformation was visible on the faulty one and the lens mount flanges all looked perfect so it is clear to me that it does not take much of a misalignment to cause this problem. Like yours mine would not even begin to rotate into locked position. For some reason during manufacture something was slightly out of whack and never picked up by QA processes.
If there are no obvious dents or dings in any of these lugs - which if present might suggest a drop onto a hard surface), one way to check further is to try a "color transfer" method. Use a thick black felt tipped pen to color the parts of the lens mount that must engage with the camera's lens mount using the felt pen. Then try mounting the lens again and check to see if there are any obvious rub marks where color has transferred from the lens to the camera's lens mount in a place which suggests it may be binding at that point. This will at least help diagnose the problem. Alternatively, if you have access to a micrometer or vernier gauge / caliper check the lugs to see if any of them are misaligned from the others. Both of these techniques are legitimate techniques used by mechanical engineers when fitting metal parts to other metal parts.
If you identify an obvious issue after doing this, come back to this thread and we can discuss options for repair. BTW felt tipped pen is ideal for this because it is thin and adds nothing to the dimensions of the lens mount and because it can be removed easily and completely with alcohol etc.
Last edited:
It would be helpful to post some pictures of the back of the lens.
Traut
Well-known
Thank you all. The screws do not seem to be the issue. The tabs may be the culprit. I will post some photos.
Traut
Well-known
peterm1
Veteran
I could be wrong but in this image it looks to me as if there is a slight distortion in the circumference of the lens base at the area where I I have placed a star shape. This may be enough to throw the geometry out of whack. Or it may be some kind of artifact of the photo, but needless to say the entire circumference of the base should be perfectly circular apart of course from the locking lugs etc. The image is IMG 5315 in your series BTW. This is the only thing I could notice though there appear to be some wear marks elsewhere as well, but these are indistinct. However, from what I could see, they do not appear to show any other distortion of the sort that I would expect to cause mounting issues. You may need to carefully measure the lugs etc.
Last edited:
I saw the same problem as Peter caught, it looks like the mount is bent.
peterm1
Veteran
BTW if it is simply a matter of correcting an inwards dent to the circumference of this ring I suspect a good technician could do it using one of those tools which are used to correct dents on a lenses' filter ring. (Look up "filter ring repair tool" if you are not familiar with them). But I suspect from your description of what happens when you try to mount the lens, that it is more complex than this and that the nearest protruding lug is also actually displaced slight downwards into the path of the lug which is meant to receive it on your cameras. (Indeed if you look closely at that lug it looks like it is slanted downwards more than it should be on the underside).
This would cause the symptom you described of it coming to a dead halt and refusing to turn at all. I am not entirely sure what would be the best way of rectifying that problem. When I have had some issues of lens adapters similarly refusing to mount because the lugs are not positioned correctly, one thing I have done is to use a thin diamond lapping plate to lap the undersides of the offending lugs till enough clearance has been achieved for the lens to mount correctly (i.e. snug but not too snug and with no binding). This may be feasible but unless you have the skills to work with metalworking tools I would suggest you entrust it to a good technician. With an offending $30 adapter I was willing to take the risk myself. However I might not be with one of these lenses which still attract a reasonably high price and when the accuracy of the repair could affect its image quality if the planes of th lens no longer aligns with the plane of the sensor......................... Up to you though.
This would cause the symptom you described of it coming to a dead halt and refusing to turn at all. I am not entirely sure what would be the best way of rectifying that problem. When I have had some issues of lens adapters similarly refusing to mount because the lugs are not positioned correctly, one thing I have done is to use a thin diamond lapping plate to lap the undersides of the offending lugs till enough clearance has been achieved for the lens to mount correctly (i.e. snug but not too snug and with no binding). This may be feasible but unless you have the skills to work with metalworking tools I would suggest you entrust it to a good technician. With an offending $30 adapter I was willing to take the risk myself. However I might not be with one of these lenses which still attract a reasonably high price and when the accuracy of the repair could affect its image quality if the planes of th lens no longer aligns with the plane of the sensor......................... Up to you though.
Traut
Well-known
Thank you. Any suggestions who to send it to evaluate and repair for a reasonable cost? Thanks again. H
Traut
Well-known
Strange thing. The lens mounted to a helicoid adapter without issue. Still won’t attach to a body. It has “hard stop”.
peterm1
Veteran
Yes this kind of thing can happen I ahve noticed with my own adapters. I have many of them as I shoot with a few different camera systems and many vintage lens makes. Differences in the manufacturing tolerances can work together or work against each other. I would expect camera mounts to be precise as a general rule- especially if you are mounting onto a Leica M mount. But I have not infrequently found lens adapters to be a little too loose or a little too tight when fitting a lens. Usually not enough to make much difference in practice but noticeable, nevertheless. Most adapters coming out of China for example are really quite cheap items when bought - $30-$50 - and so the makers do not put the same effort into quality assurance. For example, it is known that many adapters are designed to focus beyond infinity with a lens mounted because fewer people complain about this than would complain if their lens could not reach infinity. And if the makers did what they should do - design their adapters with tight manufacturing tolerances and stuck to a tight quality regime this would increase reject costs, manufacturing costs and hence selling price and reduce their market competitiveness. So they take the easy way out.
Some will makers make lenses mount on their adapters a little more loosely on the same kind of principle. In this case it works in your favour I guess.