Jump to content

Got fungus in your lens? Need it serviced by Leica?


andybarton

Recommended Posts

Advertisement (gone after registration)

I am not sure whether this is the malignant type of fungus that etches glass, It usually manifests itself in feather-like structures. I think this lens might clean up nicely with a CLA, with a bit of luck.

Link to post
Share on other sites

 

Hi guys,

 

What do you think of this problem I have with this Wetzlar lenses? Is it fungus or something else?

 

 

1.jpg
2.jpg

 

 

The Super Angulon is an OEM from Schneider, and this is deterioration of anti-reflective coating, colloquially known as "schneideritis".

Edited by ckuwajima
  • Like 1
Link to post
Share on other sites

The Super Angulon is an OEM from Schneider, and this is deterioration of anti-reflective coating, colloquially known as "schneideritis".

 

That looks a bit too extensive for Schneideritis, which is reputedly caused by the anti reflective paint peeling off and the flakes just reflecting on the glass surfaces. If it is that, it is an easy cure as it is just a strip down, clean of elements and flaking paint, repaint and reassemble. Even Schneider only used to charge €150 for a repair of this problem if nothing else found. That was a few years ago and they may charge more now. 

 

Wilson

  • Like 1
Link to post
Share on other sites

That does not look like fungus to me. It may be some kind of paint deterioration, similar to what is often found on the Minolta Rokkor 28mm lens for the Minolta CLE. I'd send the lens to Schneider in Germany and see what they say.

 

Andy

  • Like 1
Link to post
Share on other sites

Advertisement (gone after registration)

 the weather here is dry most time of the year, so I'm wondering do I need an electronic moist control camera cabinet.

 

I remember reading something about conditions for fungal growth, and just came across the following published in Community Eye Health journal in 2013 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3864060/):

 

  • relative humidity of at least 70% for more than 3 days
  • little or no airflow
  • darkness
  • nutrients (textile lint, traces of grease, varnish, dust and dirt)
The article follows with a list of actions to take to help prevent fungal growth.  I have the impression that these are being repeated from other sources, but they seem like a reasonable place to start.
  • Like 2
Link to post
Share on other sites

 

Hi guys,

 

What do you think of this problem I have with this Wetzlar lenses? Is it fungus or something else?

It’s ‘schneideritis’ which is paint on the lens element edges degrading or disintegrating. I have a SA with the same thing. It’s not a problem in practice but it devalues the lens a little. Best thing is to use the lens and not worry about it.
Link to post
Share on other sites

"Flaking paint"?? - Where does it flake to, when trapped between the glass and mount.

 

"Canada Balsam deterioration?" - nope, too modern a lens.

 

"Fungus?" - no, not around the edges of the elements in that fashion.

 

"Separation?" almost, but not quite.

 

It is a simple effect - air bells accreting in the junctions of the glass, cement layer, and/or metal mount due to slight air leakage. Just as air bells form between  the progressive freezing layers of sheet ice.  https://www.alamy.com/stock-photo/trapped-air-bubbles-in-ice.html

 

They appear white because of the differences in the refraction indices between air, and the cement, metal, or glass. A minor form of glass-to-metal separation, but not glass-to-glass separation, which is more serious optically.

 

Called "Schneideritis" and indeed the M 21 Super-Angulons were made by Schneider for Leica (thus the use of the Schneider-trademarked name). But it also appears commonly in, for example, the 28mm M-mount lens for the Minolta CLE, some (now 20 years old) Zeiss G 15mm Hologon-Gs, and even a Leitz Elmarit 28mm V3. It appears mostly with wide-angle lenses, where the "funnel shape" of the front lens opening (for capturing a wide angle of view) requires the glass to be cemented against vertical or slightly-sloped or stair-stepped "faces," rather than around the outside rim.

 

https://www.google.com/search?client=firefox-b-1&biw=1841&bih=1241&tbm=isch&sa=1&ei=yJwqW8K5CpPH_wTd6J-ABw&q=Minolta+M-Rokkor+28mm+spots&oq=Minolta+M-Rokkor+28mm+spots&gs_l=img.3...287936.288780.0.289028.6.6.0.0.0.0.109.512.5j1.6.0....0...1c.1.64.img..0.1.109...0i30k1j0i24k1.0.4tOKSyHlaTk#imgrc=_

 

Lenses with this problem can, of course, also get fungus infections (or haze, or any other optical disease) on other parts of the glass, just like any other lens. I don't see any signs of those in your sample, except maybe some haze on the deepest (central) element(s).

 

 

 

Hi guys,

 

What do you think of this problem I have with this Wetzlar lenses? Is it fungus or something else?

 

 


1.jpg
2.jpg

 

 

  • Like 1
Link to post
Share on other sites

I think that you are on the right track adan, but your 'air bells' would actually be the thin air 'space' created when the black paint on the ground outside rim of a glass element 'flakes' or more properly speaking, becomes detached from the glass. As you say, this paint has nowhere to go, so the air between it and the glass is what produces the white refraction. I suppose that it could lead to greater flare but in practice its effect is nil to negligible.

Edited by pgk
Link to post
Share on other sites

On the original topic - fungus is a life-form, with 5.1 million different species.

 

The fact that fungus is everywhere isn't important - a lens arriving at Zeiss of Leica with fungus does mean it is infected with one of the specific species that obviously likes to infect and live on glass (or glass coatings), and thus is especially dangerous to introduce into a glass-manufacturing site. Despite the fact that the surrounding wald (or factory esszimmer or küche ;) ) may be full of mushrooms, yeasts, and molds (also fungi).

 

Fungus is a heterotroph - it excretes digestive enzymes to dissolve whatever its preferred (genetically programmed) food substance is. Thus it can do lasting damage by "digesting" glass or its coatings in the posts where it grows (pitting). Just depends on the species, time of exposure, glass chemistry, and coating chemistry.

  • Like 1
Link to post
Share on other sites

I would have thought a modern lens servicing factory could have high intensity pulsed ultra-violet sources which would be used in a negatively pressurised fungus treatment compartment to kill all fungus. The compartment itself could be regularly UV flushed to kill all fungus both growing and spores. Now whether it would make economic sense to set up such a facility is a different matter. If you are separating epoxy cemented elements, the pressurised high temperature methylene chloride required to dissolve the epoxy, would also I think, be death to all fungi. 

 

Wilson

Link to post
Share on other sites

Schneideritis, and I am so disappointed it has been tolerated for so many years. I won't own another one. They have some systematic problem they won't fix. Why they have not fixed it is beyond me.

 

People write that it causes no harm, but does it have any benefit? I think not, and if it did have a benefit other manufacturers could save money by following Schneider's sloppy technique.

Edited by pico
Link to post
Share on other sites

Jac, 

 

It is not universal. I have none in my 15 year old Schneider-Kreuznach 50mm/f2.8 Componon-S lens, which I use for film scanning on a Leitz BEEON and SL601. However it may be as a dual purpose copying/enlarging lens, which may be subject to high temperatures, it is either a non-cemented configuration or uses a different epoxy balsam to the standard lenses. They are however subject to fogging. I returned the first one I bought, as it was noticeably fogged, particularly on examining in blue/UV light. 

 

Wilson

Link to post
Share on other sites

  • 3 weeks later...

I never understood the leather thing - imo one of those tropes that has been repeated around the internet for years that has become 'fact'.

 

I can see why leather cases have become 'associated' with fungus in lenses, as they can be found where conditions for fungal growth (humidity, temperature etc.) are also present, but to say that there is causation is for me a step too far.

Link to post
Share on other sites

Fungus is everywhere. Without fungus we'd have no real ale, beer, cheese, yoghurt, bread, wine, penicillin, and a host of good things in life.

 

Fungus is not a problem, it is a challenge to avoid. Leather may be a cause of fungus in lenses but where is the proof? Is neoprene better? Perhaps it is down to humidity?

 

Is there a qualified scientist to provide an answer?

 

P.S. I have no fungus on my lenses, some encased in leather and some in neoprene. I have a modern house with triple glazed windows and underfloor heating in winter. Carpets are synthetic fibre rather than wool. Lenses stored in a very dry cupboard. 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...