Nikon FM3a Film Advance Lever Not Working with Lens - Help needed

Discussion in 'Nikon' started by mikelee, Feb 2, 2021.

  1. Hey everyone,

    I've recently picked up a FM3a and is in good shape. Everything works, including the film advance lever.
    That's until I put on my lens. As soon as I put on my converted Nikkor 55mm, the film advance does not advance. It's stuck.

    I've scourged the 'net to see if there were others who share my problem, but haven't found any.
    Has anyone else experienced this problem or better yet, know what I need to do to start shooting again?

    Any and all help is welcomed.

    Thank you very much.
  2. Vincent Peri

    Vincent Peri Metairie, LA

    If you remove the lens, can you advance the lever then?
  3. Yes!
  4. Vincent Peri

    Vincent Peri Metairie, LA

    I don't have an FM3a, but the only thing inside the lens mount opening on all of my Nikon AI/AIS bodies except the FA is the lever that activates the aperture. The FA has a small button opposite the lens actuating lever that fits into the scalloped notch on AIS lenses.

    With my limited knowledge of mechanical things, I'm at a loss to explain your problem...
  5. Try another lens with the camera- does it work properly?

    If it works- I would suspect the aperture actuation lever on the lens is stuck, or just not aligning properly.
  6. ShunCheung

    ShunCheung Administrator

    If the lensโ€™ aperture mechanism has problems, it should be easy to check with it off the camera, from the rear end.
  7. As others have said, the issue is almost certainly localized to an aperture lever being stuck or dysfunctional, you just need to determine if its the lever on the lens or in the FM3a.

    Take the lens off the camera and wind the body. set a slow shutter speed like 1 sec. Press the shutter button to fire the camera while looking into its throat. On the left side of the lens mount, you should see a small folded lever drop down about half an inch toward the camera bottom at the beginning of the exposure, then pop back up. Cycle the camera several times at different shutter speeds to be sure this action is consistent and snappy, with no dragging or position changes: the lever should snap up and down instantly. If you notice any sluggishness or that the lever doesn't always return to the exact position it started, the camera needs service.

    Next turn your attention to the lens. Look at the rear mount. With the aperture/focus center line pointed straight up, the aperture lever will be on the right. Its a small tab riding in a slot. Set the aperture to f/16: looking thru the glass, the diaphragm should stop down to a small hole. While looking thru the lens, use a fingertip to flick the little aperture tab up and down in its slot. This should open the aperture all the way, if you let go at that point the aperture should instantly stop down to f/16 again. If you set the lens to its widest aperture, the reverse applies: flicking the lever should smoothly stop the lens down, letting go it should pop right back open. As with the camera body, any sluggishness, resistance or dysfunction means the lens needs service.

    You say this 55mm (is it an f/1.2 or a Micro Nikkor f/3.5?) lens was "converted" - sometimes if the conversion is done by an amateur they re-assemble the aperture ring and lever incorrectly. This either limits the motion of the tab so the lens doesn't operate at all aperture settings, or it jams the lever at wtde open or stopped down. This can make it clash or jam with the lever in the camera body. An easy fix for someone who understand how Nikkors are assembled, you might even be able to DIY while following a youTube video.

    Having said all that, there is no obvious way that mounting a lens with stuck aperture could prevent the advance lever being wound. I just checked my Nikon F2AS, FM, and Nikkormats: in each camera, using a finger to hold the aperture lever in up or down position does not prevent winding. The FM3a may of course be different somehow, but I'm not aware of any changes to the camera throat vs other lever-wound Nikon bodies (since it has aperture priority AE and manual only, it doesn't even have the AIS lens detector for shutter priority). Whatever is causing this conflict with your 55mm, you should verify the FM3a works correctly with a couple of other lenses (if you don't have any, perhaps you could borrow one at a camera store or from a Nikon-owning friend). If the problem persists with other lenses, the body need service for sure, if not something is weird with your 55mm.

    Please report back when this gets resolved, its an unusual problem so it would be helpful for others in future to know what happened with your camera.
    Last edited: Feb 4, 2021
  8. Looks like this thread may end up in the Great Black Hole of Nikon Mysteries that never reach resolution.

    Eric Sande
  9. Nope. It's definitely a bent or otherwise screwed-up aperture lever. Either in the lens or camera.

    No great mystery.
  10. I'm surprised there's an interlock between the lens body/aperture lever and the film advance lever.

    Why needed?
  11. It's a mystery because we never heard back from the OP.

  12. Yup, posted original question and disappeared the very next day.

    And that was 2 weeks ago.

    I had a similar disappearance here....

    Nikon F lens to Canon EF body, Kipon adaptor - stuck!

    Not ideal for anyone finding these threads in the future.

    In this covid World, I hope they're safe and well.

    ...and return with a positive outcome.......;)
    erichsande likes this.
  13. It's not an interlock Mike, it's a jam!
    Physically preventing the aperture lever from moving causes the whole wind-on mechanism to jam.

    I had much the same issue with a Pentax S1a. It worked fine with Pentax Takumar lenses, but would jam up with a Pentacon/Praktica lens. Simply because the Praktica lens needed extra pressure on the stop-down pin.

    Finnicky things mechanical cameras!
  14. I meant interlock inasmuch as you can't move a railway point 'cos there's a system in place to stop you UNLESS you've unlocked the interlock.

    How and why should the aperture lever have any mechanical 'connection' with the wind-on lever? Why should it care?

    Oh, unless it's the mechanism that stops you winding on mid exposure.... and the way it knows it's mid-exposure is when the body's aperture lever is closed (or open) depending on which way it goes....:p

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