Fixing FDn 100mm f/2.8. Stuck and I need help!

Discussion in 'Camera Building, Repairs & Modification' started by agphotography, Feb 19, 2011.

  1. agphotography

    agphotography Member

    Messages:
    664
    Joined:
    Mar 17, 2010
    Location:
    Orange County
    Shooter:
    Multi Format
    Hey guys,

    Well after feeling bold and fixing the lens mount on my T90 I thought "Gee it can't be that much more difficult to do the same for my wobbly 100mm."

    Well, it turns out I was wrong. I'm stuck and not sure how to proceed.

    Basically the issue with my lens was that the lens mount was quite wobbly and I could shift the lens in any direction while it was mounted on a camera.

    I removed the screws holding the rear mount and carefully removed the full thing. I found the loose screws and tightened them with a PH00 screwdriver.

    I ran into trouble when trying to put the mount back into place as I'm not sure how things are supposed to be. I eventually did get it rebuilt but I lost control of the aperture. It was stuck wide open.

    Does anyone know how to re-assemble FD lenses that can guide me through this?

    Thanks!

    - Abram


    Here are photos showing where I'm stuck. I'm not sure how to properly align these things so the lens retains control of the aperture lever.

    [​IMG]
    Photo Feb 18, 10 37 21 PM by Abram Goglanian, on Flickr

    [​IMG]
    Photo Feb 18, 10 36 41 PM by Abram Goglanian, on Flickr

    [​IMG]
    Photo Feb 18, 10 36 19 PM by Abram Goglanian, on Flickr
     
    Last edited by a moderator: Feb 19, 2011
  2. John Koehrer

    John Koehrer Subscriber

    Messages:
    6,470
    Joined:
    Apr 3, 2004
    Location:
    Montgomery,
    Shooter:
    Multi Format
    Hi Abram,
    On the last photo, there is a lever to the right of your pointer, just past the black screw. As I remember this should be spring loaded. When you look at the inside of the mount assy. There is a lever with a rectangular notch in it. The fork slips over the tab and the mount is rotated until the screw holes align. Insert screws & tighten.
    You may have to fiddle about a bit.
     
  3. agphotography

    agphotography Member

    Messages:
    664
    Joined:
    Mar 17, 2010
    Location:
    Orange County
    Shooter:
    Multi Format
    Yes I have looked inside and noticed that mechanism is controlling the aperture as it should be. I am not sure however how the "sliding grey ring" (sorry I don't know what it is called) is out of position.
    When I re assemble the lens all looks correct but as soon as I mount it to a camera or lens adapter I lose aperture control.

    I know I'm clearly doing a step wrong I just am not sure what that step is.
     
  4. John Koehrer

    John Koehrer Subscriber

    Messages:
    6,470
    Joined:
    Apr 3, 2004
    Location:
    Montgomery,
    Shooter:
    Multi Format
    If the ring is not engaged with the prong, it will only fully stop down. Sometimes it takes several tries to get them properly engaged.
    I can be a little frustrating.
    You may have to hold the stop down lever on the back of the mount to one side to align it.
     
  5. agphotography

    agphotography Member

    Messages:
    664
    Joined:
    Mar 17, 2010
    Location:
    Orange County
    Shooter:
    Multi Format
    I don't know guys... I have tried every conceivable option and every single time I re-assemble the lens I lose aperture control. I just don't understand what I'm doing wrong. I've carefully looked at all the parts and I just cannot seem to figure out what is going wrong. All I know is that as soon as I mount it on the camera, the mount shifts and screws everything up. There is nothing loose, nothing left to tighten so I cannot figure out why this is happening.