nFD 50mm 3.5 Macro front lens disassembly / teardown

Discussion in 'Canon FD' started by phil_d, Sep 5, 2015.

  1. Hi, I just got a nFD 50mm 3.5 Macro, and there is some fungus behind the first front element.
    This lens does not have a name ring that you can unscrew.
    Instead it has a conical shade that goes into the lens. The shade does not budge when you try to screw it off. Some Posts talk that this shade has 3 clips that you need to unclip from the front, but I have no luck unclipping the Hood.
    It looks like it is glued.
    Now I know that some nFD use a lot of polycarbon and Loctite.
    Is there any way that I can remove the shade without damaging it or the front filter lens ?
    (The picture below shows the front filter ring with the Shade.
    I have tried prying a plastic hotel card and shape it like a half circle and push it down between the shade and lens filter ring, to unlock the clips, but a Credit card is still too thick.
    I started carefully using a tiny screwdriver, but I hear crunching noices, just like dried cristalized glue releasing between 2 stuck pieces. I do not want to damage the Filter ring either, So I don' t Know what to do next.
    I did not pay much for the lens, but I know its a great lens, and like to get rid of the fungus...
    [​IMG]
     
  2. You may want to try a rubber sink stopper that will fit over the very top of the conical shade. I have several around here of varying sizes that I use to remove trim rings that are glued on. Just press down and twist.
    But your 50mm Macro will be a challenge. I’ve never tried to remove a trim ring as large as found on your Macro. Maybe somebody else will have an idea.
     
  3. SCL

    SCL

    When trying to repair one a few years ago I encouuntered a similar challenge. Coude easily get to rear elements, but not front. Couldn't get reliable guidance on how to resolve the problem, in spite of lots of good ideas. I finally concluded that nobody really knew. Replaced the rear element and used it for 3-4 years with no issues, before selling it.
     
  4. Hi Phil,
    Did you manage to dismantle the lens ? I have a canon 50mm F2.5 and need instructions on how to take it apart to fix the stiff focus.
     
  5. cmuseum

    cmuseum cmuseum

    The shade is clipped and glued to the filter thread element. Pour small amounts of lighter fluid between the shade and the filter thread to dissolve the glue. You can also try warming up the filter thread element to soften the glue. Keep trying to turn the shade using a rubber wrench until it breaks loose. Then open the rear end of the lens. Carefully push out the shade from behind using a strong but soft tool (you don't want to scratch the inside of the barrel). I have simply cut something from a wooden ice cream stick. HTH.
     

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