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  1. #21
    c6h6o3's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    I have never used a gray card in over 50 years of photography. I guess that I have another 50 years to learn, if I need to.
    Steve:

    I'll be happy if I can lift one in 50 years, much less use it.
    Jim

  2. #22
    Maris's Avatar
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    I've used grey cards hundreds of times with my spot-meter to identify and fix a mid grey value in complex subject matter. But it has been a frustrating process easily subject to error.

    The problem comes from the fact that grey cards are not perfect Lambertian reflectors. The"greyness" varies with the angle of the card versus the angle of the light versus the angle of the meter. In practice I'd select a meter reading when the card showed minimal glare and no shadow; concientious guesswork in effect. A good incident light meter is better.
    Photography, the word itself, invented and defined by its author Sir John.F.W.Herschel, 14 March 1839 at the Royal Society, Somerset House, London. Quote "...Photography or the application of the Chemical rays of light to the purpose of pictorial representation,..". unquote.

  3. #23
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    Quote Originally Posted by Sirius Glass View Post
    I have never used a gray card in over 50 years of photography. I guess that I have another 50 years to learn, if I need to.
    Ok all siriusness aside, when I am shooting black & white I have several ways that I may use to determine the exposure, in most used to least used:

    • General light reading without metering the sky
    • Pick out what I want to be the middle gray in the print
    • Take a general light reading without metering the sky, the brightest that I want to be zone 7 or 8, the darkest reading that I want to show the tones [zone 2 or 3] and then determine the exposure. I use this when the subject brightness range is large

    When I am shooting C-41 I have several ways that I may use to determine the exposure, in most used to least used:

    • General light reading without metering the sky
    • Pick out what I want to be the middle gray equivalent in the print
    • Take a general light reading without metering the sky, the brightest that I want to be zone 7 or 8, the darkest reading that I want to show the tones [zone 2 or 3] and then determine the exposure. I use this when the subject brightness range is large

    When I am shooting slides I have several ways that I may use to determine the exposure, in most used to least used:

    • General light reading without metering the sky

    Back to being just plain sirius.
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  4. #24
    Leigh B's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    * General light reading without metering the sky
    I don't understand "... without metering the sky".

    An incident light meter has an acceptance angle of 180°.

    The only way you could exclude the sky from the measurement would be to point the meter at the ground.

    Since the sky is a major source of illumination for the (outdoor) subject, excluding it from the measurement will give a significantly erroneous reading.

    - Leigh
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

  5. #25
    michaelbsc's Avatar
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    @Holly. Bet you never expected to stir up this hornet's nest did you?
    Michael Batchelor
    Industrial Informatics, Inc.
    www.industrialinformatics.com

    The camera catches light. The photographer catches life.

  6. #26
    Leigh B's Avatar
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    Quote Originally Posted by Maris View Post
    The problem comes from the fact that grey cards are not perfect Lambertian reflectors. The"greyness" varies with the angle of the card versus the angle of the light versus the angle of the meter.
    The instructions with the card say to point it midway between the primary light source and the lens axis and meter from the camera position.

    Amazing how easy things are when you RTFM (Read The Fine Manual).

    - Leigh
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

  7. #27
    Sirius Glass's Avatar
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    Quote Originally Posted by Leigh B View Post
    I don't understand "... without metering the sky".

    An incident light meter has an acceptance angle of 180°.

    The only way you could exclude the sky from the measurement would be to point the meter at the ground.

    Since the sky is a major source of illumination for the (outdoor) subject, excluding it from the measurement will give a significantly erroneous reading.

    - Leigh
    My recommendations are relevant to reflectance metering only. How would one use an incident light meter to get spot readings of the brightest and the darkest areas?

    How would one use a gray [grey] card with an incident meter? ==> Ill Elephant!
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  8. #28

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    Some years back Calumet either sold or used as a promotion a plastic 8x10 gray card. It seemed like a clever idea and I cut mine into smaller more manageable pieces. I keep them in my camera bags just in case. On an early fall trip to Yellowstone one evening it was really freezing and early the next morning the windshield was frosted - it came in very handy as an ice scraper. (as well as the original intention with my spot meter - measure twice, expose once)

    http://www.jeffreyglasser.com/

  9. #29
    IloveTLRs's Avatar
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    Quote Originally Posted by Holly View Post
    I'm so ashamed not to have more knowledge on this, I've only ever understood the use of grey cards in theory and not ever actually put one to use in my work.
    I've been shooting for years and I still don't know what gray cards are used for
    Those who know, shoot film

  10. #30
    Sirius Glass's Avatar
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    Quote Originally Posted by IloveTLRs View Post
    I've been shooting for years and I still don't know what gray cards are used for
    The gray cards are used to match the tone of the sky on any typical day in Rocherster New York.
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

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