Tamron 90mm focusing mechanism clutch

Discussion in 'Digital SLR' started by achilleaslazarides, Nov 27, 2006.

  1. Hello,
    I have a Tamron 90mm lens. This lens has a screw drive AF mechanism
    (I'm talking about Nikon mount). To switch to MF, one can simply slide
    the focus ring back, and the AF disengages; it's then possible to focus
    manually without setting the camera to MF (which retracts the AF

    The problem is the following: When I slide the MF ring back,
    disengagament is not complete. I can focus, but sometimes the part that
    mates to the screw also rotates (I can see this when the lens is not on
    the camera). Obviously, this way I may damage the camera or lens if I
    am not careful. Using AF, there is no problem; using MF is also
    perfectly safe as long as I switch to MF from the camera too,
    retracting the screw.

    So, has anybody else had a similar problem with this (or another,
    similar lens), did they get it fixed, and how much did it cost? I don't
    really see a reason to fix it as it does not affect operation (except
    in slowing me down a bit), but if it's cheap I may send it at some

    achilleaslazarides, Nov 27, 2006
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  2. achilleaslazarides

    mfshadow Guest

    Sounds normal (and frustrating) to me. I've got the same lens for my
    Nikon system and Canon system, the Nikon does have to be switched to
    manual on the body as well.
    mfshadow, Nov 28, 2006
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  3. No, it is not normal. Until 2 days ago, sliding the lens focusing ring
    back allowed me to focus manually without moving the AF/MF switch on
    the camera to "M". It did this by (as I explained in my first post)
    disengaging the part that is driven by the screw in the camera body
    from the focusing mechanism (ie you could focus but that thing did not
    turn; you therefore do not have to switch the camera to "M" in order to
    retract the screw).

    If your lens did not allow this, it's broken.

    Thanks for the reply.
    achilleaslazarides, Nov 29, 2006
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