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Biotar 2/58 T - fungus
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PostPosted: Wed May 02, 2012 12:28 am    Post subject: Biotar 2/58 T - fungus Reply with quote
Hello,
I got the Biotar 2/58 T which is bad conditioned, but for free.
I'd like to save him. Is there any chance?
I know, that I should buy a new one but there isn't a lot of Praktina mount lenses and if someone offer them, the price is quite big for me...



Good light Smile
Jan


PostPosted: Wed May 02, 2012 12:37 am    Post subject: Reply with quote
Jan, it can be cleaned, this will at least prevent that the fungus develops further more, however, given the level of infection,
it is likely that even after cleaning there will be marks left on the glass.
How those marks may influence the image quality, that is not easy to predict. For sure the red T coating is a good thing because
it will reduce the quantity of parasite light entering the lens.

In any case, a Zeiss red T Biotar is a lens that deserves a tentative.
If you take it to a service, ask them for an estimate. Usually here fungus cleaning ends up costing 40-50 Euros depending on the complexity of the lens and the depth of infection.
I would say that up to 50 Euros, a cleaning is worth. For more than 50 Euros, better buy another copy.


PostPosted: Wed May 02, 2012 12:49 am    Post subject: Reply with quote
Orio, thank a lot for your quick reply. I'd like to try the cold creme after study methods of cleaning lenses from a fungus. It seems to me like a cold creme is less invasive than ammonia. But I might be wrong.
What do you think?


PostPosted: Wed May 02, 2012 1:03 am    Post subject: Reply with quote
Jan wrote:
Orio, thank a lot for your quick reply. I'd like to try the cold creme after study methods of cleaning lenses from a fungus. It seems to me like a cold creme is less invasive than ammonia. But I might be wrong.
What do you think?


Ammonia cleans the surface but does not remove the spores.
Since fungi live on oxygen, I would say that you should use what best kills oxygen-based life forms, that is, Chlorine.
So I would try with Sodium Hypochlorite (Bleach) obviously diluted in water.


PostPosted: Wed May 02, 2012 1:18 am    Post subject: Reply with quote
Thank you, I'll try it with Sodium Hypochlorite (which concetration?) and post results (I have "test season" in school and I'd like fix it properly, so it will take some time...). Smile


PostPosted: Wed May 02, 2012 1:43 am    Post subject: Reply with quote
Jan wrote:
Thank you, I'll try it with Sodium Hypochlorite (which concetration?)


I don't know, but I think that weak concentration (like 1 to 20) can be sufficient.
If you doubt that it's efficient, try 1 to 10 (maybe use a mask to avoid direct inhalation of fumes, and use eyeglasses)
You will have to repeat the cleaning, first clean, then rinse, then clean again, until you are sure everything is gone, because you may remove a layer of fungus, but there will probably be another layer underneath.
Spores are persistent, even if you see nothing, they might still be there, so at the end of the cleaning process,
when you see nothing more left, I would still leave the glass submerged for some minutes inside the solution, before the final rinse.
DO NOT rub hard, or you will ruin the T coating! GENTLE rubbing only, and with a soft cloth, do NOT use brush.
Better repeat gentle rubbing many times, than doing hard brushing one time.


PostPosted: Wed May 02, 2012 1:45 pm    Post subject: Reply with quote
Hello Jan,

I have cleaned lenses in very similar condition as the one you have with 2 or three times the cold cream treatment. Non of them have shown fungal growth again (yet).

In my experience i've never had good results with amonia, chloride, acetone, vinegar, ethanol or isopropanol but you might have different luck.

Like Orio said, there might be marks of the fungi left on the lens after cleaning but it depends on the type, like i said i've had some like yours cleaned completely with almost no marks and others with only a couple of small spots leaving clear marks on the lens.

The cold cream treatment i use is 20 minutes, clean with soap and water, and repeat the treatment accordingly.

Hope you rescue this lens


PostPosted: Wed May 02, 2012 3:14 pm    Post subject: Reply with quote
Well if you can not rescue this lens let me know i have a Biotar F2 with a broken focus Helicoid and very nice glass that i can sell if needed for parts.


PostPosted: Wed May 02, 2012 5:35 pm    Post subject: Reply with quote
Thank you guys a lot! I'm happy there's somebody who rescue old things (unhappily I met a lot of young people who said "throw this old waste.. look at my new blablabla..." But they don't want find the power and the beauty of these amazing apparatuses.

Eddieitman, thank you for your offer. I try to fix it and if it fail, I'll let you know.

Good light and steady hand wish
Jan
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