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Thread: long exposure metering ..

  1. #1

    Default long exposure metering ..

    hi bros / sis
    i understand that doing day time long exposure i need to calculate the exposure metering and then down my shutter speed according to the " stops " , my ND filter offers.
    the above mention is done in " Manual Mode "

    But which mode should i use to get the initial reading becoz in " manual mode "
    there will be no input, everything is done manually ..

    Just Shoot It ...

  2. #2

    Default Re: long exposure metering ..

    Quote Originally Posted by allenleonhart View Post
    use ur camera to get ur normal reading first.

    throw in ur nd filters.

    note how many stops ur nd filters require u to compensate, u can now either make ur shutter speed longer to compensate for the stop difference, or u can increase ur aperture or both.

    like ur camera meters a reading of erm...

    iso 100, f8, 1/60 sec.

    now ur nd filter ur using is nd8, meaning u need to compensate 3 stops.

    so... u can either: open up ur aperture by 3 stops,

    so it shld become iso 100, f2, 1/60sec
    or u can choose to make a slower shutter speed by 3 ev stops

    iso 100, f8, 1/15 sec

    or a mix.

    iso 100, f4, 1/30sec

    i not too sure if i'm right. someone can comfirm this pls? i also wanna know if what i think i know is right
    Sounds logic to me ... but which mode would u use to get the " normal " reading ?
    Just Shoot It ...

  3. #3
    Moderator catchlights's Avatar
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    Default Re: long exposure metering ..

    set your camera on manual exposure mode, look into the viewfinder, pay attention on the electronic analog exposure display (#21), when the indicator set at 0, means correct exposure, so you just change the ISO, shutter speed, or aperture, to make the indicator goes to 0.

    or you can go and read your user manual, the "Exposure" chapter.

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  4. #4
    Moderator Octarine's Avatar
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    Default Re: long exposure metering ..

    Quote Originally Posted by fatBozZ View Post
    Sounds logic to me ... but which mode would u use to get the " normal " reading ?
    Which metering mode or which exposure mode? Seems you need more understanding what the camera does.
    Use the metering mode according your scene, read the manual about the various metering modes (matrix, center weighted, spot).
    Use an exposure mode that allows the chosen metering mode. in "Auto" most cameras fall back to Matrix (or the respective equivalent of the maker / model). Usually Aperture Priority Mode and Shutter Priority Mode allow you to select metering modes freely. Make sure that EV is set to "0".
    Use Manual mode as catchlights just described.
    Last edited by Octarine; 10th July 2010 at 04:15 PM.
    EOS

  5. #5

    Default Re: long exposure metering ..

    oh .. so for example without ND filter meter read 1sec 22f ev value at 0 --> perfect exposure
    with ND 8 filter which is 3 stops
    i can prolong the shutter speed by 3 stops fStop remain at 22 and have a good exposure ?

    Just Shoot It ...

  6. #6
    Moderator catchlights's Avatar
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    Default Re: long exposure metering ..

    Quote Originally Posted by fatBozZ View Post
    oh .. so for example without ND filter meter read 1sec 22f ev value at 0 --> perfect exposure
    with ND 8 filter which is 3 stops
    i can prolong the shutter speed by 3 stops fStop remain at 22 and have a good exposure ?

    yes, that is correct.
    Shoot to Live, Live to Shoot
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  7. #7
    Moderator Octarine's Avatar
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    Default Re: long exposure metering ..

    Quote Originally Posted by fatBozZ View Post
    oh .. so for example without ND filter meter read 1sec 22f ev value at 0 --> perfect exposure
    with ND 8 filter which is 3 stops
    i can prolong the shutter speed by 3 stops fStop remain at 22 and have a good exposure ?
    Correct in terms of Maths. But do note the possible softening of image due to diffraction when using very small aperture opening. Use f/16 at maximum.
    EOS

  8. #8

    Default Re: long exposure metering ..

    For an idea of how the numbers (ISO, aperture and shutter speed) are linked to each other

    http://www.fredparker.com/ultexp1.ht...IP%20CHART%20B

  9. #9

    Default Re: long exposure metering ..

    To all that replys my Thread !!! Thank you all Shifu ( Master )

    Just Shoot It ...

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