Minolta Autometer 3 Stops Off

Discussion in 'Minolta' started by cc011, Aug 19, 2004.

  1. cc011

    cc011 Guest

    Hi, I bought an Autometer IIIf really cheap, but when placed under the
    10 am sun, it shows 1/1000s, f16, ASA100. Other than that, it seems
    consistent. I suppose I could use it by setting the ASA value 3 stops
    lower but it's just a bit annoying. Does anyone know if there is a easy
    fix/recalibration? Or is there a service manual available online?

    By the way, it's not because of a dirty sensor, which would cause the
    meter to be off towards the other direction.

    GH
     
    cc011, Aug 19, 2004
    #1
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  2. Hi;
    There is a calibration potmeter in the battery compartiment
    Arnold
     
    Arnold Mervielde, Aug 19, 2004
    #2
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  3. cc011

    Alan Browne Guest

    If you had the dome pointing at the sun, then you would tend to
    read fast ... but not as much as you say.

    With the sun at some elevation at 10 am, point the dome of the
    meter at the horizon in the direction of the sun ... not directly
    at the sun. When you do this, don't stand over a light
    refelcting surface like white concrete or even grey asphalt.
    Over grass would be a good place. That should get you 1/100 @
    f/16 for ISO 100 film.

    If that gives you this 3.5 stop diff, then get it calibrated.
    There is no calibration setting on the IIIf IIRC.
    Correct.
     
    Alan Browne, Aug 19, 2004
    #3
  4. cc011

    Nostrobino Guest

    My Auto Meter IV F has an adjustment screw inside the battery compartment,
    but it's only for minor calibration touch-ups. It's full range is less than
    a full stop in either direction, in 1/10-stop increments.

    N.
     
    Nostrobino, Aug 19, 2004
    #4
  5. cc011

    Matt Clara Guest

    I had that happen on one I bought used. Ended up trading it in on a Sekonic
    L358.
     
    Matt Clara, Aug 19, 2004
    #5
  6. << Hi, I bought an Autometer IIIf really cheap, but when placed under the
    10 am sun, it shows 1/1000s, f16, ASA100. >>

    GH-

    Are you sure about this? It is hard to believe it could be that far off. I
    would expect operator error instead! Do you have the owner's manual?

    Are you using the plastic diffuser when pointing towards the sun? If so, try
    removing the diffuser and pointing the photocell towards the northern sky while
    standing in the shade. That should read approximately 1/ISO at f/16.

    Another possibility would be that the ASA (ISO) reading has a bad digit, and
    you really had it set to ASA 1000. If that had been the case, your reading
    would have been a reasonable value, within a fraction of a stop.

    Fred
     
    Fred McKenzie, Aug 21, 2004
    #6
  7. cc011

    Matt Clara Guest

    When this problem happened to me, someone here mentioned an endemic problem
    with these light meters and the pin coupling the dome to flash. Literally,
    I was shooting in a studio, when I double checked my meter readings after
    shooting for a few minutes, without adjusting my lighting, and the meter
    had gone from indicating f5.6 to f22. Exactly three stops.
     
    Matt Clara, Aug 21, 2004
    #7
  8. cc011

    cc011 Guest

    Yes, I am pretty sure. I also borrowed a color meter from a friend for
    comparison and essentially confirmed my observation. The color meter has
    a flat defuser vs the dome defuser on my Autometer but the difference
    should not be very small.
    I will try that when the weather gets better here in NJ. I assume the
    northern sky should be cloudless, right?
    That's not it either. I can set ASA from 12 to 6400 at 1/3 stop with all
    zeros showing.

    GH
     
    cc011, Aug 21, 2004
    #8
  9. cc011

    Alan Browne Guest

    As I stated in an earlier post, you will get a Sunny-16 reading
    when you point the dome at the horizon _under_ the sun (not at
    the sun). Pointing at a blue northern sky will give less light
    and indicate a slower speed than the ISO setting.

    Cheers,
    Alan
     
    Alan Browne, Aug 21, 2004
    #9
  10. cc011

    Nostrobino Guest

    That looks like four stops to me, Matt.

    N.
     
    Nostrobino, Aug 23, 2004
    #10
  11. cc011

    Alan Browne Guest


    As I stated in an earlier post, you will get a Sunny-16 reading
    when you point the dome at the horizon _under_ the sun (not at
    the sun). Pointing at a blue northern sky will give less light
    and indicate a slower speed than the ISO setting.

    (sorry if this is posted twice ... server probs).

    Cheers,
    Alan
     
    Alan Browne, Aug 23, 2004
    #11
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