Is that fungus?

Discussion in 'Camera Building, Repairs & Modification' started by cmo, Feb 16, 2012.

  1. cmo

    cmo Member

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    Someone offered me a super-telephoto lens that might fit into my budget, but he says it has fungus and a small scratch at the outer edge of the front lens. Here I have a photo... what do you think, is that fungus, and can it be fixed? It's on one of the inner lenses.
     

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  2. Ian Grant

    Ian Grant Subscriber

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    Looks more like separation of the front lens cell.

    Ian
     
  3. jordanstarr

    jordanstarr Member

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    I second seperation. Shouldn't have a noticeable effect though on longer lenses though as opposed to wider-angle lenses unless it gets bigger.
     
  4. jochen

    jochen Member

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    yes, this is a beginning lens separation. It may get worse by mechanical impact (too much and unsymmetrical force by the threaded hold ring) and by temperature changes since the different lenses and the cement have slightly different thermal expansion.
     
  5. cmo

    cmo Member

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    Thanks, that's a surprise... can such a problem be cured or is the lens doomed?

    It's such a pity... a Canon FD 5.6/800mm L lens...
     
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  6. jochen

    jochen Member

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    Hello,
    theoretically the two lenses have to be separated completely, can be difficult because of the synthetic cement. Then they are cleaned and recemented. The biggest problem ist: They have to be centered exactly. Only a very skilled repairman with the appropiate equipment (e.g. the CANON service) could do this. Another possibility would be to exchange the lens group. But I think the probability that they have a suitable and matched lens group for such an "old" lens as a spare part is very small and the price would be extremely high. Maybe someone here knows an independent repairman for separated lenses.
     
  7. Ian Grant

    Ian Grant Subscriber

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    There's a thread on the LF forum on doing these repairs. It is possible to do it yourself separating the elements and re-cementing with UV cured synthetic optical cement. It's a bit tricky though.

    The UK based company who used to do this as well as repolishing and recoating went out of business about a year ago unfortunately.

    Ian
     
  8. himself

    himself Member

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    instead of starting my on, I thought it would be a good idea to hijack this one :wink:

    so is this fungus?
    DSC_0414.jpg

    I was given a olympus pen ft from a friend and I'm waiting to to have the roll of film I put through it developed to see how much of a problem this lens is... considering how difficult it can be to focus through - I'm guessing a lot

    anyway, I originally hoped it was condensation, but I can't get it to clear, so now I fear the worse. A shame considering the lens
     
  9. John Koehrer

    John Koehrer Subscriber

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    Doesn't look like fungus to me but the 1.2 for the OLY pen f is a VERY uncommon lens and should be well worth while having cleaned.
     
  10. jordanstarr

    jordanstarr Member

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    on an 800mm lens, you likely will not notice any effect on separation this small. But as stated earlier, if it gets worse, you might.
     
  11. dehk

    dehk Member

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    First one can be beginning of a crack from the sides too.
     
  12. himself

    himself Member

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    that's what I originally thought, but I just can't get it to clear.
    Easier said than done too, I'm in Warsaw and only know one camera repair place that's a bit, well, how do I put this?

    anyway, you're right well worth getting it look at by someone that can at least disassemble it, not least because the camera belonged to quite a famous Polish artist and it would be a shame if this lens went to waste now.
     
  13. himself

    himself Member

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    so managed to get the lens apart and it looks like it isn't fungus, but problem is; where I had thought the problem was between the first and second element it's actually in the second element group... I can't separate these.

    now I know the lens is a good'un but this is serious repair right? is it worth it?