Faulty aperture Nikon 300mm f4 AFS?

Discussion in 'Nikon' started by anthony_bez, Apr 11, 2010.

  1. Hello,
    I have just bought a unused Nikon 300mm f4 AFS lens from a private seller. But unfortunately the aperture stops closing after f8, I can select f4, f5.6 and f8.
    Has anyone had experience of this and likely cost of repair?
     
  2. ShunCheung

    ShunCheung Administrator

    In the US, Nikon USA would change the entire aperture diaphragm. I had that done on two lenses back in the 1990's, and Nikon USA charged about US$250 each. You are probably looking into something close to 200 Pounds??
     
  3. Thank you for the advise Shun.
    I am waiting for a reply from the seller. I just hope he was not aware of the fault, and it happened in transit?
     
  4. Are you sure you have the aperture set to the highest aperture on the lens itself and the little locking tab is in the lock possition?
    Ray
     
  5. I don't know if the AFS mechanism is similar to the AF (non-S) mechanism, but I had a similar problem with the 300mm f/4 AF lens. The lever inside the barrell had become disconnected from the aperture blades and the local authorized repair shop wanted US$325 (the standard price for servicing this lens) to fix it.
    Turns out the lever (remarkably flimsy) was slightly bent & mis-aligned and it took about 15 minutes to figure out the problem and bend the lever back into alignment.
     
  6. Are you sure you have the aperture set to the highest aperture on the lens itself and the little locking tab is in the lock possition?​
    The blades are not closing after f8.
    Turns out the lever (remarkably flimsy) was slightly bent & mis-aligned and it took about 15 minutes to figure out the problem and bend the lever back into alignment.​
    I was hoping it may be a simple fix.. How did you access the lever?
     
  7. "How did you access the lever?"
    Remove the tiny screws that hold the rear light baffle in place & remove the baffle.
     
  8. Douglas,
    Thank you for your advise and reply.....
    I can now see the lever is binding on the light baffle. Hopefully if I bend it back into alignment as you suggested it should solve the problem.
    I have not attempted the fix yet as I have still not received a reply from the seller.
    Best Regards
    Anthony
     

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