Shutter irregularities

Discussion in 'Large Format Cameras and Accessories' started by esearing, Sep 28, 2004.

  1. esearing

    esearing Subscriber

    Aug 17, 2004
    North GA
    4x5 Format
    I have a Schneider 180mm in a Copal 1 shutter. I was shooting over the weekend at sunrise and ran into an interesting problem. (using Type 55 Polaroids)

    If I shot at f8 for 1/2 second my polaroids were fine. If I shot at f11 for 1 second they were drastically over exposed.

    The speeds all seem correct by sound but apparently the 1 second speed is off. Prior shots seemed ok around 1/60th and 1/125th.

    How often do you shoot 1 second exposures?
    Is it worth getting it fixed or replacing the shutter for 1 false speed?
    Are shutter irregularities just something you get used to, and compensate for?

    thanks in advance
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Sep 7, 2002
    Honolulu, Ha
    Large Format
    Sounds like it's time to have the shutter cleaned and serviced. This is just routine maintenance, and slow speeds usually are the first to go off.

    Meanwhile, if the subject is static, you can just take two 1/2 sec. exposures, if 1/2 sec is accurate.

    Alternately, use the B setting and a metronome or a watch with a second hand. Set the metronome to 120 and subdivide the beat, so you're counting 4 beats per second, and you can easily time a 1 sec. bulb exposure accurately. Musicians do this all the time and are able to time motions not unlike pressing and releasing a shutter cable with an accuracy of a few thousandths of a second. I find it works well with times from 1/2 to 5 sec. More than that, and you can just look at the second hand on a watch.
  3. Tom Hoskinson

    Tom Hoskinson Member

    Mar 7, 2004
    Southern Cal
    Multi Format
    Carol Miller in Whittier, CA will CLA a LF Copal shutter (and other LF shutters) for $45.00 (if no part replacements are reqd.). She is fast and good!