Page 1 of 2 12 LastLast
Results 1 to 10 of 14

Thread: affect of fungus on lens performance/quality

  1. #1

    Join Date
    Mar 2006
    Location
    Coast of Oregon
    Posts
    455

    affect of fungus on lens performance/quality

    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.)

  2. #2

    Join Date
    May 2007
    Location
    Minnesota
    Posts
    370

    Re: affect of fungus on lens performance/quality

    Darryl, no experience with fungus(thank god ) 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?
    Last edited by Brian Bullen; 15-Aug-2007 at 11:04. Reason: clumsy

  3. #3

    Join Date
    Mar 2006
    Location
    Coast of Oregon
    Posts
    455

    Re: affect of fungus on lens performance/quality

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

  4. #4

    Re: affect of fungus on lens performance/quality

    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

  5. #5

    Join Date
    Oct 2004
    Location
    S.W. Wyoming
    Posts
    1,137

    Re: affect of fungus on lens performance/quality

    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.

  6. #6

    Join Date
    Mar 2006
    Location
    Coast of Oregon
    Posts
    455

    Re: affect of fungus on lens performance/quality

    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".

  7. #7

    Join Date
    Mar 2006
    Location
    Coast of Oregon
    Posts
    455

    Re: affect of fungus on lens performance/quality

    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. ???

  8. #8

    Join Date
    Apr 2005
    Location
    England
    Posts
    570

    Re: affect of fungus on lens performance/quality

    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.

  9. #9

    Join Date
    Feb 2007
    Location
    Winchester, MA
    Posts
    166

    Re: affect of fungus on lens performance/quality

    Hydrogen peroxide; cigarette ash as a polishing aid.

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

  10. #10

    Join Date
    Apr 2005
    Location
    England
    Posts
    570

    Re: affect of fungus on lens performance/quality

    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.

Similar Threads

  1. Trousse Parisienne Casket Lens Set
    By John Downie in forum Lenses & Lens Accessories
    Replies: 13
    Last Post: 14-Jun-2014, 18:32
  2. Kodak Master View Lens Boards
    By Michael A.Smith in forum Cameras & Camera Accessories
    Replies: 8
    Last Post: 15-Mar-2008, 06:15
  3. My stupid lens question.
    By e. a. smith in forum Lenses & Lens Accessories
    Replies: 30
    Last Post: 20-Mar-2007, 15:54
  4. B&L Tessar IIb "6-1/2 x 8-1/2" barrel lens
    By Doug Kerr in forum Lenses & Lens Accessories
    Replies: 6
    Last Post: 13-Feb-2007, 00:52
  5. Gundlach-Manhattan Hyperion Diffusion Lens on E-bay
    By Alex_2242 in forum Lenses & Lens Accessories
    Replies: 1
    Last Post: 31-Aug-2001, 13:44

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •