Praktica PLC3 meter off by two stops with Tamron adapter

Discussion in '35mm Cameras and Accessories' started by pschauss, Mar 30, 2008.

  1. pschauss

    pschauss Member

    Nov 29, 2002
    I have a Praktica PLC3, an M42 mount camera, which uses an electrical connection to to the lens to allow open aperture metering. It meters correctly in open aperture mode with the Pentacon 50mm/f1.8 lens. When I use it with a Tamron 35-80 f3.8-4 lens and a Tamron electric adapter it overexposes by about a stop and a half.

    As I understand it, the Praktica electric mount system expects the lens to tell it what the maximum aperture is and what it will be when the camera stops the lens down. With the Tamron zoom mounted my camera is acting as though it thinks that the maximum aperture is 1.8 instead of f3.8. Short of buying an electric lens, how can I determine whether the fault is in the camera or the adapter?
  2. Anscojohn

    Anscojohn Subscriber

    Dec 31, 2006
    Medium Format
    Try using a ball-point eraser on the electrical contacts in the Tamron adapter mount. Sometimes oxidation changes the resistance without completely blocking the current.

    John, Mount Vernon, Virginia USA