Zeiss Opton Sonnar Haze, Fungus or Damaged Coating

[stuart_115]

Hi all,
I have obtained a Zeiss Opton F1,5 50mm Sonnar lens. I was wondering if anyone can see whether the front element has fungus, haze or a damaged coating. To me is looks like haze.

I was also wondering if it could be cleaned like it's done here by Mike Elek:http://elekm.net/zeiss-ikon/repair/sonnar-clean.html

 

[lukx]

It looks like most of the coating on the front element has rubbed off, leaving only heavily damaged coating on the sides of the glass. You would be more likely to find haze on the elements in front of and behind the aperture blades, so further toward the inside of the lens. There might be haze present in there, the lens looks quite cloudy. But I say it's not what we see at the front.

I don't think there is fungus there.

 

[stuart_115]

Thanks.
I guess I just have to use it, shoot with it and see the results 🙂.

 

[xayraa33]

Some of the last made West German Zeiss f1.5 50mm Sonnars are known for lens element separation...the story goes that Zeiss used something else than the traditional balsam to cement the lens elements and it did not hold up as well as time went on and the lens aged.

 

[markjwyatt]

A sad sight to see. Hope you did not pay too much for this.

 

[Mark C]

Some of the last made West German Zeiss f1.5 50mm Sonnars are known for lens element separation...the story goes that Zeiss used something else than the traditional balsam to cement the lens elements and it did not hold up as well as time went on and the lens aged.

Looks like that to me. Or maybe "all of the above".

 

[stuart_115]

Looks like that to me. Or maybe "all of the above".

It's quite likely.

A sad sight to see. Hope you did not pay too much for this.

I may have over paid.😉 The seller did indicate that the state of the lens was not well, however I thought I would be able to clean it and make it look like brand new.

 

[jcb4718]

I'd have a go with it. You may find the images are still sharp enough but just low contrast.

 

[Highway 61]

I would say it's neither fungus nor decementing nor coating delamination due to improper cleaning methods but water damage (leading to heavy coating damage and internal haze, and, probably, corroded aperture blades).

It can probably be salvaged. Best case, you end up with an uncoated front element (you can remove all the coatings with some Flitz or some Miror and some cotton balls without etching the glass, then you carefully clean the front element with dishwashing soap, tap water and your fingers). Worst case, the cemented groups are getting opaque and cannot be cured. Worst of the worst case, the aperture blades can break because of the corrosion.

The condition of the rear element surface and of the rear group optics will tell it all. Coating damage, even if heavy, as well as slight scratches at the front element can be turned out with a good cleaning and a good lens hood. A damaged rear element surface, or damaged rear group optics, often mean a ruined lens. The condition of the middle group will have some effects on the results too but the condition of everything being between the aperture blades and the film is what will make it.

Of course it has to be taken apart in full before you tackle any cleaning job and yes, Mike Elek's instructions are very good, the postwar f/1.5 Sonnar is built like the postwar f/2 Sonnar so you take it apart and reassemble it the same way.

See also : http://elekm.net/zeiss-ikon/repair/collimate/

 

[stuart_115]

I would say it's neither fungus nor decementing nor coating delamination due to improper cleaning methods but water damage (leading to heavy coating damage and internal haze, and, probably, corroded aperture blades).

It can probably be salvaged. Best case, you end up with an uncoated front element (you can remove all the coatings with some Flitz or some Miror and some cotton balls without etching the glass, then you carefully clean the front element with dishwashing soap, tap water and your fingers). Worst case, the cemented groups are getting opaque and cannot be cured. Worst of the worst case, the aperture blades can break because of the corrosion.

The condition of the rear element surface and of the rear group optics will tell it all. Coating damage, even if heavy, as well as slight scratches at the front element can be turned out with a good cleaning and a good lens hood. A damaged rear element surface, or damaged rear group optics, often mean a ruined lens. The condition of the middle group will have some effects on the results too but the condition of everything being between the aperture blades and the film is what will make it.

Of course it has to be taken apart in full before you tackle any cleaning job and yes, Mike Elek's instructions are very good, the postwar f/1.5 Sonnar is built like the postwar f/2 Sonnar so you take it apart and reassemble it the same way.

See also : http://elekm.net/zeiss-ikon/repair/collimate/

Thanks I will have a look at it. The rear element looks good so thats comforting 🙂

 

[Grytpype]

I'd agree with Highway 61. I had a 1940 collapsible f2 Sonnar which had been coated, post-production, and had a front element so well 'cleaned' that the surface was matt.

I was told that polishing it would destroy any optical precision remaining, but having nothing to lose, I polished it with red rouge powder ('jewellers rouge'?) until it had a good finish (took a very long time). I was surprised afterwards that I could still see the colour of the coating, and even more surprised to find that the result of a test-shot was sharper than the same shot taken with a good uncoated lens!

Definitely worth trying a repair.
​

 

[stuart_115]

I'd agree with Highway 61. I had a 1940 collapsible f2 Sonnar which had been coated, post-production, and had a front element so well 'cleaned' that the surface was matt.

I was told that polishing it would destroy any optical precision remaining, but having nothing to lose, I polished it with red rouge powder ('jewellers rouge'?) until it had a good finish (took a very long time). I was surprised afterwards that I could still see the colour of the coating, and even more surprised to find that the result of a test-shot was sharper than the same shot taken with a good uncoated lens!

Definitely worth trying a repair.​

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A small update. I have removed the front retaining ring and had access to the three groups. Except from the front element all other elements are clear and look in a very good state.😱

The next step is indeed to polish the front element with the red rouge powder.