light meter calibration

Discussion in 'Exposure Discussion' started by chrisofwlp, Jul 26, 2006.

  1. chrisofwlp

    chrisofwlp Member

    Jul 25, 2006
    Prescott, Ar
    8x10 Format
    i need to find someone who calibrates light meters, and by that i mean adjust it to read 18% gray. i bought a used minolta spotmeter f a few months ago and given its unclear history i thought it better to spend a few bucks on calibration rather then waste time and far to many $4 a sheet 8x10 chromes.

    KEH will do it for $100, and i can't seem to find anyone else who will do it.
  2. wildbill

    wildbill Member

    Nov 28, 2004
    Grand Rapids
    Multi Format
    Quality Light Metric co. in hollywood
    $50 i think
    the only place to get it fixed as well
    The nice thing about this meter that most don't know is it's user adjustable. Under the battery cover you'll see a phillips screw. Find someone with another accurate spot meter and compare the two. You could try an slr as well. I calibrated mine this way initially.

    vinny walsh
  3. Chan Tran

    Chan Tran Member

    May 10, 2006
    Aurora, IL
    I have a problem as well. I have 3 meters. A minolta flashmeter III, spotmeter M and flashmeter VI. Between the flashmeter III and flashmeter VI in incident mode they read virtually the same. Between the spotmeter M and flashmeter VI in spot mode the M read lower than the FM 6 in most cases but in certain condition it reads higher than the FM 6. I know I can adjust the reading with either meter but not in this case. It seems that the FM 6 picks up more of the spectacular reflection than the spot M. Very diffused surface the 2 read about the same. Also the spot M seems to have more flare that it would read higher if aimed at a dark spot with a bright surrounding.
  4. RalphLambrecht

    RalphLambrecht Subscriber

    Sep 19, 2003
    Medium Format
    Do it yourself. The Minolta meters have an adjustment knob in the battery compartment. Use your Kodak Gray Card and apply 'sunny-16' on a clear and sunny day. This will allow for consistency betwen meters under daylight conditions. Verify with a roll of film and make adjustments by going to 'sunny-11.5' if you wish.
  5. Michael Kadillak

    Michael Kadillak Member

    Nov 16, 2003
    Your initial instincts are correct. Quality Light is a fabulous place to get this work done as their prices are reasonable and their work is deadly accurate.

    Metering linearity is the objective as any meter is simply a mechanical instrument and always subject to induced error as a function of time. Calibrate your photography to a known industry standard (the properly properly calibrated meter you regularly use in the field) and perform this task every other year. Older shutters are another place where I feel that one should do a shutter test and get a CLA on these shutters when necessary. Film costs are expected to incease in costs in the future so it just makes sense to take any risk variable that we have control of out of the equation. I shoot ULF and LF and the costs are already over the top and until I find that I have enought experience that I do not need to reach for an exposure meter when in the field, a professional meter calibration at least every other year is a very prudent and intelligent thing to do.