THIS CAN'T WORK! Zeiss Opton 50mm F1.5 Sonnar T in a J-3 mount.

Sonnar Brian

Sonnar Brian

Product of the Fifties
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One of our RFF members picked up an oddity, a Zeiss Opton 50mm F1.5 Sonnar T converted to Leica Mount using a Valdai Jupiter-3 focus mount. I tried this 20 years ago- it just cannot be screwed deep enough into the mount to focus properly. Machining is required. Too much machining. The lens was off, and was asked to take a look. Also was offered for sale, as an option. That's good, I knew how much it would cost me if I totally screwed it up satisfying my need to know. I've had one-way-disassembly before, just to find out how something worked.

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Well that can't work! Glad it could not, otherwise my observation 20 years ago would be wrong.

The J-3 mount was slightly bored out, and the rim that would normally cover the gap to the Aperture ring of the J-3 had been cut out.

SO- no way to make this work. Fortunately, I had one parts Zeiss Opton 50/1.5 with the variable stand-off ring, mount, and guide screw. I also have a $70 Chinese Contax to LTM adapter that could only be used with internal mount lenses, machining was off on the external flange.

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I let the "then" owner know that drastic surgery was required, but the operation was a total success. Posted these images.L1025071.jpgL1025072.jpgL1025069.jpgL1025074.jpgL1025075.jpgL1025076.jpgL1025077.jpg
The offer to buy the lens stood, it's mine now.

And- the Jupiter-3 focus mount could be used to convert the 1934 5cm F1.5 Sonnar to Leica Mount. That was today's project. I still need to find a sleeve to cover the gap between the mount and aperture ring as you focus, but it works just fine.

So in the end, this was the case of the Incredible Two Lens Head Transplant...
 
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Erik van Straten said:
Brian, what is your opinion on the Fotofox adapters?

Erik.
Click to expand...
The latest one that I bought cannot be adjusted for using with external mount lenses. The pair made a few years ago could be adjusted to line up with external mount lenses. SO- the ones available now are fine for use with internal mount 50mm lenses, and are cheap at ~$75. It is ashame that the redesign was simplified to the point of negating a prime feature.
 
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Thank you, Brian. Brian, is it essential for correct focusing that when the adapter is positioned on infinity the fixed red dot (behind the moving ring with the metal clip) is exactly in the middle between the two screws that hold the metal clip? I mean for focusing close up.

Erik.
 
The adapter itself lines up with infinity correctly with the RF of my cameras. It does not have a distance scale. I use the two original adapters with a very good Jupiter-9, Zeiss Opton 85mm F2, early CZJ 13.5cm F4, and CZJ 8.5cm F4 Triotar. Bought the third one hoping to dedicate to the Zeiss Opton 85. I was happy to find a good use for it.
 
Well done, Brian!
Didn't you convert (many years ago) some lenses by using J-3 barrels? Is it special with the Opton?
 
gelatin silver print (1934 sonnar 50mm f1.5) leica m3

Erik.

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After I saw this picture, I changed the position of the red dot on the adapter a bit to the left. Now it is exactly between the two screws on the clip. I hope this helps making the focusing more precise. In this picture the maximum sharpess is not on the head of the figure, but on the vegetation behind her. This picture is on full aperture.
 
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raid said:
Well done, Brian!
Didn't you convert (many years ago) some lenses by using J-3 barrels? Is it special with the Opton?
Click to expand...
The shape of the barrel prevents it from screwing deep enough into the J-3 focus mount. I tried this years ago.
 
Erik van Straten said:
gelatin silver print (1934 sonnar 50mm f1.5) leica m3

Erik.

View attachment 4816583


After I saw this picture, I changed the position of the red dot on the adapter a bit to the left. Now it is exactly between the two screws on the clip. I hope this helps making the focusing more precise. In this picture the maximum sharpess is not on the head of the figure, but on the vegetation behind her. This picture is on full aperture.
Click to expand...
The frustrating part about this adapter- the design translates the full movement of the external mount Contax lens to the movement required for the RF of the Leica. The pitch of the adapter's helical takes care of this. The downside- the movement is not enough for the internal mount Zeiss lens, it comes up ~0.1mm short. It is perfect for an Internal mount Nikon S-mount lens. I adjusted the variable stand-off ring on my Zeiss Opton as I would a Jupiter-3 to work on the camera.

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

EDITED: The design of this adapter has been changed and it can no longer be adjusted for external mount lenses. For internal Mount lenses- the adapter works correctly. I will be keeping my two "first-version" adapters. The newer ones- dedicated for an internal mount lens only. I have a total of...
www.rangefinderforum.com www.rangefinderforum.com
 
Thank you, Brian, I guess I have to live with this insufficient movement of the adapters helical for the internal mount Zeiss lenses. Are there adapters (for Leica) that work well with the internal Zeiss lenses? I like this Zeiss lens more than the Nikkors.

Erik.
 
Amedeo has an adapter for internal mount Zeiss lenses that I use- it has an indexed cam, and focus is perfect across the full range. He has the same adapter with a straight cam for the Nikkor lenses. I have a later 50mm F1.5 Sonnar on one Amedeo adapter, and the Millenium Nikkor on another. The focus direction is the same as Leica.

I also have a Zeiss Opton 50mm F1.5 at Skyllaney for conversion to M-Mount.
 
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Yes- Skyllaney converts the CZJ lenses to M-Mount. They also have a custom adapter for the 8.5cm F2. Converting lenses to Leica mount is their specialty. I gave Chris at Skyllaney a 4cm F1.4 Biotar (early lens, before the Sonnar was made) and a 35mm F2 Fastax mount Wollensak Raptar that had been in my parts bin for years. He converted both to M-Mount. I dabble in conversions, Chris does it professionally. Both lenses are rare, wanted to help him out during Covid. I admire him and his efforts. I converted my other 35/2 Raptar to Contax mount using a J-12.




skyllaney.com

Conversions

Skyllaney Opto-Mechanics is able to convert non-rangefinder lenses to become LTM/ M mount lenses with full RF coupling using a variety of methods.
skyllaney.com skyllaney.com
 
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I used a 40.5mm filter ring, bored it out and polished down to cover the threads. It fits inside the focus ring, very tight fit. Keep the threads covered. Ready for use.

All shots wide-open.
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Just think. After I'm gone, someone will put this lens up for sell on Ebay as a rare prototype...
 
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