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Thread: erratic light meter

  1. #1

    Default erratic light meter

    Hi all, got a little problem with my recently acquired L-408 meter. After calibration with gray cards, i find that the spot meter and incident readings are almost the same ( at the most less than 2/10 of a stop difference). The biggest problem is that calibrations for low light levels ( for example indoors ) and bright areas (outdoors, under sunlight) are way off. I have found 3 different calibrations for the meter :

    When using flash indoors : -2/3 stop
    ambient light indoors : -1 1/3 stop
    ambient light outdoors( quite bright) : + 2/3 stop

    i could live with the problem if the calibration is consistently the same for all lighting conditions, but it seems to me that the meter is not linear. Does anyone know if this is a common problem and how much would it cost to get this fixed?

  2. #2
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    Default Re: erratic light meter

    Prehaps you would like to give more details about what steps you are doing for your calibration? The calibrations are off, meaning comparing spot with incident readings?
    I've used one before, and I find the sensitivity of the spotmeter to be a little bit inconsistent in ambient low light.
    Last edited by Prismatic; 12th July 2008 at 08:28 PM.

  3. #3

    Default Re: erratic light meter

    Hi prismatic, actually what i meant was that the readings from the incident and spotmeter were quite consistent. For the spotmeter, i calibrated it with a grey card held near the subject whereas in incident mode i just held the meter near the subject. The actual deviations occur when i use the lightmeter in different lighting conditions (ambient low light, sunlight and flash) where i must dial in different iso offsets for these scenarios. Strange huh?

  4. #4

    Default Re: erratic light meter

    Quote Originally Posted by stonko View Post
    Hi all, got a little problem with my recently acquired L-408 meter. After calibration with gray cards, i find that the spot meter and incident readings are almost the same ( at the most less than 2/10 of a stop difference). The biggest problem is that calibrations for low light levels ( for example indoors ) and bright areas (outdoors, under sunlight) are way off. I have found 3 different calibrations for the meter :

    When using flash indoors : -2/3 stop
    ambient light indoors : -1 1/3 stop
    ambient light outdoors( quite bright) : + 2/3 stop

    i could live with the problem if the calibration is consistently the same for all lighting conditions, but it seems to me that the meter is not linear. Does anyone know if this is a common problem and how much would it cost to get this fixed?
    Why should you be calibrating your light meter? They come factory calibrated and you should not touch if if you don't have proper references for calibration. The only thing I can think of is that your grey card is wrong or the way you do it is wrong.

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