Voigtlander S NOKTON 50mm F1.5 Aspherical

A. Maci

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Hello Everyone,

I'm new to the forum and I'm hoping to seek some advice regarding a recently purchased Voigtlander S NOKTON 50mm F1.5 lens.

The lens would not mount properly on my Nikon S3 or SP. I set the camera and lens to infinity, line up the indexing dots, and turn the lens into place but it does not "click" into position or engage with the focusing mechanism.

I have to turn the focus away from infinity and fiddle back and forth before it will engage and "click" with the focusing mechanism.
This most likely means that the focus distance isn't reported accurately, and I am unable to focus the lens down to 0.9m as the focusing mechanism stops around 1m.

It's unlikely to be an issue with my camera bodies, since other S-mount lenses do mount properly.

Did I get a defective copy of the lens? I'm not sure if Voigtlander ever produced a version for the Contax mount, which might also causing this issue.
But the paperwork and box that came with this lens clearly states that its for the Nikon S mount / Bessa R2S. The engraving at the front of the lens also has the yellow S.

Unfortunately due to the low numbers produced, there isn't much information I could find about these S-mount Voigtlanders online.

Thanks in advance.
 

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Hi I know the problem that you are talking about. Last year I purchased a S mount Nokton and had the same issue. Only sometimes I could manage to mount it onto my camera, and the focus distance readings were way off. Fortunately I figured out what was wrong and it was a quite simple fix.

On the back of the lens where there the lens couples to the rangefinder mechanism m, there’s a spring loaded rangefinder coupling ring. It’s this ring that tells the camera what distance the lens is focused at. This ring is held on by a retaining ring. This retaining ring must have loosened on your lens, which meant that the coupling ring is also loose, turning freely.

On your other outer bayonet S mount lenses check the orientation of their rangefinder coupling ring and then turn the one on your lens to the same position. Then secure it down using its retaining ring.

Hopefully that will fix your problem.

Kind regards Nathan
 
Hi Nathan,

Thanks for taking the time to reply.

I went to take a closer look, and you were very close to discovering the issue.

The spring loaded coupling ring on my lens is indeed misaligned. It seems that the notch circled in image 1 should be aligned to the indexing dot and infinity mark, based on my other S-mount lenses.

But the coupling ring on this lens is secured properly, and it does not rotate freely. There is a screw partially blocked by the ring itself (Image 2). I'm not sure if that's the screw securing the coupling ring or how I can access it.

I also noticed that the position of the coupling ring seems to be mechanically coupled to the focusing ring itself. (Image 3)

The screws A and B hold down a plate that rotates with the focusing and coupling rings. The notch on the coupling ring is marked as D.
Plate C functions as the infinity hard stop as it does not move and physically stops the focusing ring from rotating past infinity.

It looks like I could loosen screws A and B, and rotate the focusing ring to align the coupling ring with the indexing dot.
Essentially by moving screws A and B slightly to the right of their current positions. This should allow the notch to match where the indexing dot is.

But that would mean that the focus markings on the lens would still be wrong, as it will focus past infinity and be unable to focus down to MFD.
I'm also concerned that the 2 screws are also securing other internal lens components, and I could be destroying the lens by loosening the screws.

Or maybe I'm misunderstanding the situation entirely.

Would anyone know how I should proceed, or recommend any repair shops that are familiar with these lenses?

Thank you.
 

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Hi I know the problem that you are talking about. Last year I purchased a S mount Nokton and had the same issue. Only sometimes I could manage to mount it onto my camera, and the focus distance readings were way off. Fortunately I figured out what was wrong and it was a quite simple fix.

On the back of the lens where there the lens couples to the rangefinder mechanism m, there’s a spring loaded rangefinder coupling ring. It’s this ring that tells the camera what distance the lens is focused at. This ring is held on by a retaining ring. This retaining ring must have loosened on your lens, which meant that the coupling ring is also loose, turning freely.

On your other outer bayonet S mount lenses check the orientation of their rangefinder coupling ring and then turn the one on your lens to the same position. Then secure it down using its retaining ring.

Hopefully that will fix your problem.

Kind regards Nathan

Hi Nathan,

Just an additional thought, realised I'm not too sure what the retaining ring you mentioned looks like.

Does it refer to the ring with the 2 notches in the attached image?

It's tight on my lens, but did you mean that I could loosen this ring to reposition the coupling ring?

Thank you.
 

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Hi Nathan,

Just an additional thought, realised I'm not too sure what the retaining ring you mentioned looks like.

Does it refer to the ring with the 2 notches in the attached image?

It's tight on my lens, but did you mean that I could loosen this ring to reposition the coupling ring?

Thank you.
Yes that’s the retaining ring that I was talking about. When it was loose on my lens the coupling ring could be repositioned easily.
 
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