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Thread: Is that fungus?

  1. #1
    cmo
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    Is that fungus?

    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.
    Attached Thumbnails Attached Thumbnails pilzbild_Cropped.jpg  
    The future belongs to the few of us still willing to get our hands smell like fixing bath.

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    Ian Grant's Avatar
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    Looks more like separation of the front lens cell.

    Ian

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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.

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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.

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    cmo
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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...
    Last edited by cmo; 02-16-2012 at 06:55 AM. Click to view previous post history.
    The future belongs to the few of us still willing to get our hands smell like fixing bath.

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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.

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    Ian Grant's Avatar
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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

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

    so is this fungus?
    Click image for larger version. 

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    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

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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.
    Heavily sedated for your protection.

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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.

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