Inexpensive Chinese Contax Mount to LTM- Maybe a little work required.

These are the two, on opposite ends of the mount.

The other way to do this for 1981 and 1982 Helios-103: there is a secondary shim for the rear group. I filed one down to move the rear farther from the image place and lower the focal length. Not as easy, and only works on early ones.
 
So loosen these two screws and remove the lens mount and get at the rear lens block and loosen this lens block 1/2 turn and re-assemble and you are done?
 
xayraa33 said:
So loosen these two screws and remove the lens mount and get at the rear lens block and loosen this lens block 1/2 turn and re-assemble and you are done?
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No just loosen the screws - grab the lens by the front/aperture ring and gently (as to not shear off the aperture control pin) twist it CCW for about half a turn. Tighten screws back up. A digital (focus adjusted for infinity with a known-good-leica lens) camera would help here to show you exactly how much to unscrew it. But 1/2 turn sounds right to me. Also rather unscrew more than less - front focus is always more benign photographically speaking than back focus.
 
Just loosen the screws, unscrew the barrel 1/2 turn in the mount, and tighten the screws down. No need to remove the barrel from the mount. No need to re-index the aperture ring.
 
If this ends up driving up the prices for Helios-103 in the end I'm gonna be very cross though. One of the most lovely undervalued lenses for the Contax mount. And basically the only affordable, fast, non-Sonnar 50mm lens for it. (Excluding the Olympic Nikkor and its re-issue)
 
The Menopta, as shown and adjusted, on the Nikon S3.

menopta-wideopena.jpg


And the Millenium Nikkor 50/1.4 at F1.8, on the same S3. The Menopta was $25, the Nikkor cost more.

nikkor-f18a.jpg
 
The Menopta (A rebadged Helios-103), wide-open on the S3.

menopta-wo-3a.jpg


Anyone remember I bought about 10 of these, and adjusted them for the Nikon users here- around 2006 or so. Tom A got one, used it on his Nikon.
 
xayraa33 said:
Here is a video about the Helios 103...at point 4:19 in the video he takes out a shim...is this the shim you file down on the 1981 and 82 version? by how much do you reduce the thickness of this shim...do you still unscrew the rear lens block by 1/2 turn even if you thin out the rear shim?

https://www.youtube.com/watch?v=CrExVkN7NVM&t=289s
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Yes- he is showing a 1982 Helios-103, which has the secondary shim. Later ones do not have this.

Reduce the shim by about 0.2mm. Do not move the barrel in the mount if you reduce the shim.
 
Sonnar Brian said:
Just loosen the screws, unscrew the barrel 1/2 turn in the mount, and tighten the screws down. No need to remove the barrel from the mount. No need to re-index the aperture ring.
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OK, with this simple procedure does the aperture ring dot and scale now appear on the bottom of the lens once it is mounted on a camera...I mean you did turn it 180 degrees?
 
The Menopta and Helios-103 have two index dots for the aperture and two full sets of aperture scales. Move it 180 degrees- it all lines back up. Contax mounts rotate 270 degrees through the focus range.

The $15 I used to charge was mostly for my time spent at the Post Office sending the lens back out.
 
Since the aperture dot is on the not rotating part of the barrel yeah the index dot will be "misaligned." you can however simply use a white sharpie pen and make a new dot on the black rim. It should be enough for shooting it.

Or with a tiny bit of more effort you can reset the aperture index properly. It's again quite easy and not as daunting as it seems. Take out the three screws of the aperture ring. Rotate it so it will sit correct. Set the screws back in finger-tight. In my experience the friction is enough to hold the aperture scale in place. Doing it properly would be tapping screw holes. But if you just want to quickly shoot the lens it's not really needed.
 
TenEleven said:
If this ends up driving up the prices for Helios-103 in the end I'm gonna be very cross though. One of the most lovely undervalued lenses for the Contax mount. And basically the only affordable, fast, non-Sonnar 50mm lens for it. (Excluding the Olympic Nikkor and its re-issue)
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I picked up 1 at a camera show for $2. They used to go for well under $20. The Menopta was an export version, found they had tighter tolerances. You cannot find them anymore.
 
TenEleven said:
Since the aperture dot is on the not rotating part of the barrel yeah the index dot will be "misaligned." you can however simply use a white sharpie pen and make a new dot on the black rim. It should be enough for shooting it.

Or with a tiny bit of more effort you can reset the aperture index properly. It's again quite easy and not as daunting as it seems. Take out the three screws of the aperture ring. Rotate it so it will sit correct. Set the screws back in finger-tight. In my experience the friction is enough to hold the aperture scale in place. Doing it properly would be tapping screw holes. But if you just want to quickly shoot the lens it's not really needed.
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The Helios-103 and Menopta (export version) have two Index Dots for the aperture Scales- there are two full sets, 180 degrees apart. Move 1/2 turn, no need to do much of anything. If you try to fine-tune past 1/2 turn, then make new dots.
 
Sonnar Brian said:
The Menopta and Helios-103 have two index dots for the aperture and two full sets of aperture scales. Move it 180 degrees- it all lines back up. Contax mounts rotate 270 degrees through the focus range.

The $15 I used to charge was mostly for my time spent at the Post Office sending the lens back out.
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So with a 1983 Helios 103 the procedure is extra simple: loosen the two screws on the chrome lens mount, turn lens out by the front black part 180 degrees, re tighten chrome lens mount screws ...no worries about the aperture scale being on the bottom because it is doubled up in its engraving..now the Helios will focus good on a Nikon S2 at close distance and lens set at f1.8 , correct ?
 
xayraa33 said:
So with a 1983 Helios 103 the procedure is extra simple: loosen the two screws on the chrome lens mount, turn lens out by the front black part 180 degrees, re tighten chrome lens mount screws ...no worries about the aperture scale being on the bottom because it is doubled up in its engraving..now the Helios will focus good on a Nikon S2 at close distance and lens set at f1.8 , correct ?
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The focal length will still be a bit different (longer) - but, for my own purposes I've "contaxed" a Nikon S2 (by increasing the mount shim and doing nothing else) and I found it focuses perfectly up close even at f/1.5 with no issues that I can detect. Whatever residual discrepancy there is, it is not enough to show up on film. I guess you could probably see it with digital & pixel peeping.

So long answer short - if you get infinity correct then the close focus (especially at f/1.8) will be totally fine on your S2.
 
TenEleven said:
The focal length will still be a bit different (longer) - but, for my own purposes I've "contaxed" a Nikon S2 (by increasing the mount shim and doing nothing else) and I found it focuses perfectly up close even at f/1.5 with no issues that I can detect. Whatever residual discrepancy there is, it is not enough to show up on film. I guess you could probably see it with digital & pixel peeping.

So long answer short - if you get infinity correct then the close focus (especially at f/1.8) will be totally fine on your S2.
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I like to leave the shims on the Lens mount on my Nikon S2 alone so it will focus perfectly fine with its native Nikkor 5cm f 1.4 lens or any Nikon S lens I buy in the future..I just want to be able to use the several Helios 103 lenses I got laying around on the Nikon S2 and on the LTM Canons once I buy a Fotofox adapter.

Question : So If I got earlier Helios 103 lenses, 1980, 1981 and 1982 vintage with that rear shim as shown in that video at point 4:19...then I cannot use the simple procedure of loosening two screws on that rear chrome lens mount and turning the lens gently from the front CCW 180 degrees and tightening the two screws in the chrome lens mount ?
 
xayraa33 said:
I like to leave the shims on the Lens mount on my Nikon S2 alone so it will focus perfectly fine with its native Nikkor 5cm f 1.4 lens or any Nikon S lens I buy in the future..I just want to be able to use the several Helios 103 lenses I got laying around on the Nikon S2 and on the LTM Canons once I buy a Fotofox adapter.
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I am aware of that. Perhaps we're having a miscommunication here.

My point was: Screwing the Helios-103 out by half a turn, or in my case modifying the S2 to have thicker shims achieves the same thing. Namely it moves the optics in relation to the film plane, so it will work correctly for the intended (in your case a Nikon S2) camera. After doing that all residual focus error is negligible.
 
TenEleven said:
I am aware of that. Perhaps we're having a miscommunication here.

My point was: Screwing the Helios-103 out by half a turn, or in my case modifying the S2 to have thicker shims achieves the same thing. Namely it moves the optics in relation to the film plane, so it will work correctly for the intended (in your case a Nikon S2) camera. After doing that all residual focus error is negligible.
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What I find confusing is on the 1983 vintage Helios we move the lens assembly out from the film plane but on earlier Helios lenses we reduce the thickness of the shim in the chrome lens mount...would not that bring the whole lens assembly closer to the film plane now?
 
xayraa33 said:
What I find confusing is on the 1983 vintage Helios we move the lens assembly out from the film plane but on earlier Helios lenses we reduce the thickness of the shim in the chrome lens mount...would not that bring the whole lens assembly closer to the film plane now?
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You are right. But the shim is between two optical groups. As indicated in my crude drawing below.
This does two things - it shortens the focal length (from ~52.4mm actual closer to 51.6mm actual - the Nikon/Leica standard) and also moves the rear lens slightly further out from the focal plane. It's a two for one. Hope that clears things up.

index copy.png
 
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