affect of fungus on lens performance/quality

[Darryl Baird]

After hoping to get lucky with an EeeBeyh auction, I got a Wollensak Velostigmat Series II lens with some fungus. In assessing my "luck" I wonder how much, and what kind of visual effect might be in the final negative?

Does anyone have examples or tales to share about pictures with fungus?

I've attached a macro shot of the critter, about 14mm at the widest points. (It doesn't look that bad in most light, but at an oblique angle it's hairy.)

[Brian Bullen]

Darryl, no experience with fungus(thank god:D ) but I'm curious how it looks on the ground glass. Did you try it out visually to see what effect it has, the ground glass should be enough to know if it's going to be a problem?

[Darryl Baird]

no, it isn't on a lensboard yet... I have to make one before I can view/test it!

[Gordon Moat]

You could try placing it in the sun for a few days. Quite often that can minimize the fungus already present.

Last lens I got with some fungus was on a Petri 7S rangefinder. Upon disassembly, it seemed that the fungus was between cemented pairs, which is not possible (practical) to repair. So after bleaching the element pairs in the sun for a few days, I was left with a faint outline of the fungus. Upon reassembly I rotated the fungus to be mostly out of the 35mm frame. If it appears, it might only be at the edges. Unfortunately, your lens has fungus nearly dead centre.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Glenn Thoreson]

It shouldn't be hard to disassemble for cleaning. If you can get some ammonia (the real thing, not the household stuff) you may be able to remove it.
The larger question is: has it etched the glass?
That can only be determined after cleaning. This type of fungus excretes hydroflouric acid, which will etch the glass if not removed. On the other hand, you may have a unique soft focus lens out of the deal.

[Darryl Baird]

thanks Gordon, I left a similar fungus-plagued lens (a Zeiss Tessar) in the sun for a few days and the fungus did retreat, but the lens appears to have the etched death. This fungus looks to my eye much less dense, very much like an old cobweb.

Glenn, yes, I thought about the soft focus angle... but the particular problem posed with this lens design is the front element rotates (unscrews) forward to produce variable (0-5) softness levels. With a fungus mucking up the sharp spot, it could be difficult to get the same effect as a non-fungus version. I have the same lens design (Series II) in a 12" and I'm getting happy with it, thus this purchase on FleaBay of the 9.5".

[Darryl Baird]

on closer inspection the fungus appears to be on the front surface.

QUESTION: Can I use anything other than Ammonia? I have Acetone and denatured alcohol on hand. ???

[Rob_5419]

Try Hydrogen Peroxide 2%.

It works okay, not applied neat, but swabbed.

You might have to quarantine that thing otherwise it might turn up with foot & mouth disease all over the rest of your lenses.

[sparq]

Hydrogen peroxide; cigarette ash as a polishing aid.

http://www.mypentax.com/Fungus.html
http://herron.50megs.com/fungus.htm

[Rob_5419]

Wow. The guy's practically written a thesis on this stuff.

Never realised anyone else really used Hydrogen peroxide apart from blondes and bombers. Now we can add bokeh hunters to the list.

[Darryl Baird]

Wow. The guy's practically written a thesis on this stuff.

Never realised anyone else really used Hydrogen peroxide apart from blondes and bombers. Now we can add bokeh hunters to the list.

...funny, I was thinking about writing a visual thesis (if all else failed), entitled "How flare ruined my style or how I managed to turn ebay madness into aesthetic nirvana." Alternate titles might include: "Too much softness for one man to bear" and "You can't see the forest for the flare" ...sorry, the alcohol fumes are going to my brain

on a happy (lucky) note, the denatured alcohol removed the fungus for the time being

[Don Hutton]

Wow. The guy's practically written a thesis on this stuff.

Never realised anyone else really used Hydrogen peroxide apart from blondes and bombers. Now we can add bokeh hunters to the list.
And Cyanotype printers....

[Rob_5419]

Thanks for reminding me Don. If the peroxide don't get me, the cyanide will...

Darryl - quit dreaming! The fungal hyphae will still be around. Make sure you stack a dessicant with your lens for the next few months at least.

[seawolf66]

Guys: I got a Wollensak F6.3 5x7 lens that was fungus and soft haze , I use a small drop of Orange cleaner on the lens and in a minute wiped it off let lens sit for a day before putting it back to gether and all is fine at the moment but I do check it from time to time: