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metering & 18% grey - Photography

greets all. been getting a little more "serious" with my camera and was hoping someone could clear up a question i have re: metering. NikonN65 in manual mode .. typical 75/25 centerweighted meter. taking a picture of a BLACK chair. (for arguments sake)... 'measurements': a reading from the inside of my palm (dont have a grey card) the camera/meter reads: 1/30 f/4.5 a reading from the back of the chair (black fills the frame): 1.5seconds f/4.5 thats about 5 stops different! why are these so far apart? where is my mistake? which is the correct exposure? curve ball: in AperaturePriority ...

  1. #1

    Default metering & 18% grey

    greets all.
    been getting a little more "serious" with my camera
    and was hoping someone could clear up a question i have
    re: metering.

    NikonN65 in manual mode .. typical 75/25 centerweighted meter.

    taking a picture of a BLACK chair.
    (for arguments sake)...

    'measurements':

    a reading from the inside of my palm (dont have a grey card)
    the camera/meter reads: 1/30 f/4.5

    a reading from the back of the chair
    (black fills the frame): 1.5seconds f/4.5

    thats about 5 stops different!

    why are these so far apart? where is my
    mistake? which is the correct exposure?

    curve ball: in AperaturePriority
    the black chair reads 1/20 f/4.5
    ... why the one stop difference?

    cant figure out what MatrixMetering is reading
    because it INSISTS on using the flash.

    any ideas?
    thanks in advance.
    -tony


    tony Guest

  2. #2

    Default Re: metering & 18% grey

    >
    > thats about 5 stops different!
    >
    > why are these so far apart? where is my
    > mistake? which is the correct exposure?
    You've made no mistake. If the light falling on your gray card (palm) is
    the same as the light falling on the chair, then that is the correct
    exposure. If you meter something solid black, or solid white for that
    matter, your meter will try and make it 18% grey. That's its job.
    Relax... all is well.
    >
    > curve ball: in AperaturePriority
    > the black chair reads 1/20 f/4.5
    > .. why the one stop difference?
    Probably using a different metering pattern. And don't meter the black.
    >
    > cant figure out what MatrixMetering is reading
    > because it INSISTS on using the flash.
    If you are in an auto mode, the camera will want to use flash when the
    shutter speed falls below about 1/60. Just meter the gray card.
    >
    > any ideas?
    > thanks in advance.
    > -tony
    >
    >
    >
    --
    John O.
    There is no slack in light attack.
    John O. Guest

  3. #3

    Default Re: metering & 18% grey


    "tony" <antoniogattahotmail.com> wrote in message
    news:lv7Qa.23056$it4.583542news1.tin.it...
    > greets all.
    > been getting a little more "serious" with my camera
    > and was hoping someone could clear up a question i have
    > re: metering.
    >
    > NikonN65 in manual mode .. typical 75/25 centerweighted meter.
    >
    > taking a picture of a BLACK chair.
    > (for arguments sake)...
    >
    > 'measurements':
    >
    > a reading from the inside of my palm (dont have a grey card)
    > the camera/meter reads: 1/30 f/4.5
    >
    > a reading from the back of the chair
    > (black fills the frame): 1.5seconds f/4.5
    >
    > thats about 5 stops different!
    >
    > why are these so far apart? where is my
    > mistake? which is the correct exposure?
    >
    > curve ball: in AperaturePriority
    > the black chair reads 1/20 f/4.5
    > .. why the one stop difference?
    >
    > cant figure out what MatrixMetering is reading
    > because it INSISTS on using the flash.
    >
    > any ideas?
    > thanks in advance.
    > -tony
    >
    This is EXACTLY what we would expect ...
    Take a look at this [url]http://www.normankoren.com/zonesystem.html[/url] I hope it
    will explain it for you :-)



    Not in my trousers Guest

  4. #4

    Default Re: metering & 18% grey

    In article <lv7Qa.23056$it4.583542news1.tin.it>,
    "tony" <antoniogattahotmail.com> wrote:
    > greets all.
    > been getting a little more "serious" with my camera
    > and was hoping someone could clear up a question i have
    > re: metering.
    >
    > NikonN65 in manual mode .. typical 75/25 centerweighted meter.
    >
    > taking a picture of a BLACK chair.
    > (for arguments sake)...
    >
    > 'measurements':
    >
    > a reading from the inside of my palm (dont have a grey card)
    > the camera/meter reads: 1/30 f/4.5
    >
    > a reading from the back of the chair
    > (black fills the frame): 1.5seconds f/4.5
    >
    > thats about 5 stops different!
    >
    > why are these so far apart? where is my
    > mistake? which is the correct exposure?
    >
    > curve ball: in AperaturePriority
    > the black chair reads 1/20 f/4.5
    > .. why the one stop difference?
    >
    > cant figure out what MatrixMetering is reading
    > because it INSISTS on using the flash.
    >
    > any ideas?
    > thanks in advance.
    > -tony
    >
    >
    Assuming all the readings are taken with the same incident light:

    Your palm (if clean :-) should read 1 stop over mid-tone. Therefore the
    more correct exposure based on your palm should be 1 stop more than the
    meter, or 1/15 f/4.5 . This is the reading you would have obtained
    with a grey card if you had one at the time.

    Why the black chair reads what it does? I don't know. I would have
    expected someting more like 2 or 3 stops from 1/15 f/4.5 .

    --
    Rudy Garcia

    Rudy Garcia Guest

  5. #5

    Default Re: metering & 18% grey

    Here's some info about this:

    [url]http://www.bythom.com/graycards.htm[/url]

    Paul
    /////////////////

    "Norman Worth" <nworthearthlink.net> wrote in message
    news:4kkQa.99468$Io.8549956newsread2.prod.itd.ear thlink.net...
    > Meters are typically calibrated to give correct exposure at 12 percent
    > reflectance. An 18 percent gray card (Zone V, for those who use the zone
    > system) will give the right exposure with a little margin when metered.
    > Your hand (Zone VI) will be about one stop brighter - 1 stop less
    exposure.
    > The black chair (Zone I or II, depending on the cirstances) will ask
    for
    > three or four stops more exposure. The meter is indicating the exposure
    > assuming 12 percent reflectance. Your hand is reflecting more than 12
    > percent, the chair less.
    >
    > The Nikon cameras have truly marvelous exposure meters. For general
    picture
    > taking, they are almost foolproof. They even compensate for most uneven
    > lighting situations. But they can be fooled by truly unusual subjects,
    such
    > as very light or dark scenes that you want to show as truly light or dark.
    > In these cases, you can use the exposure compensation feature on the
    camera
    > and bracketing to get the right exposure.
    >
    > "tony" <antoniogattahotmail.com> wrote in message
    > news:lv7Qa.23056$it4.583542news1.tin.it...
    > > greets all.
    > > been getting a little more "serious" with my camera
    > > and was hoping someone could clear up a question i have
    > > re: metering.
    > >
    > > NikonN65 in manual mode .. typical 75/25 centerweighted meter.
    > >
    > > taking a picture of a BLACK chair.
    > > (for arguments sake)...
    > >
    > > 'measurements':
    > >
    > > a reading from the inside of my palm (dont have a grey card)
    > > the camera/meter reads: 1/30 f/4.5
    > >
    > > a reading from the back of the chair
    > > (black fills the frame): 1.5seconds f/4.5
    > >
    > > thats about 5 stops different!
    > >
    > > why are these so far apart? where is my
    > > mistake? which is the correct exposure?
    > >
    > > curve ball: in AperaturePriority
    > > the black chair reads 1/20 f/4.5
    > > .. why the one stop difference?
    > >
    > > cant figure out what MatrixMetering is reading
    > > because it INSISTS on using the flash.
    > >
    > > any ideas?
    > > thanks in advance.
    > > -tony
    > >
    > >
    > >
    >
    >

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    Paul Brecht Guest

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