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  1. #31
    MattKing's Avatar
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    There is a difference between the ISO standard for film and the ISO standard for digital, but that probably isn't the biggest problem with using any camera (not just digital cameras) to meter for another camera.

    The biggest problem is that cameras are systems themselves, and each part of the system can add variation.

    For instance, if there is a marked difference between the light transmission of the lens (the "T-stop") and the aperture of the lens (the f stop) then reading the f stop will introduce variation.

    If the shutter speeds vary in accuracy between the two cameras, and the reading obtained using the digital camera is adjusted or exposure, then the difference in the two shutters will introduce a variance.

    The exposure systems in digital cameras are designed to give good exposure with a system that is more like slide film than negative film. The ISO standard for film is oriented toward negative film. Differences in films often require us to develop separate and distinct EIs for films that have similar ISO ratings.

    It is no doubt possible to, through care and experience, develop a customized approach to making use of the information from a digital camera's meter (or any other camera's meter) to expose film in another camera, but the differences between the two systems do make it necessary to both be very careful about metering technique (such as using a standard focal length on a zoom lens) and to be very precise about using the right EI - customized to that particular combination of cameras, lenses and film.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  2. #32
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    Quote Originally Posted by pentaxuser View Post
    Ben, can you link us to the test you refer to?. The body to which you refer has either got it right and the fact is that wiltw's test and noparking's execution of it is simply luck or the body had got it wrong( seems unlikely) or there is a way of reconciling these apparent opposite conclusions which may be the most likely explanation.

    Thanks

    pentaxuser
    I can't give you a link because I read it in the actual magazine about four years ago that I still have somewhere but can't lay my hands on at the moment, but I can assure you that Professional Photographer did extensive test with E6 and C41 film and several different DSLR camera sensors using a Minolta Autometer 1V F hand held light meter and the test results convinced me, anyway this isn't really a subject for a forum dedicated to film photography, and I only read the article out of interest since I let the digiheads worry about such matters, because I don't own a DSLR
    Last edited by benjiboy; 11-05-2012 at 12:57 PM. Click to view previous post history.
    Ben

  3. #33
    benjiboy's Avatar
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    Quote Originally Posted by MattKing View Post
    There is a difference between the ISO standard for film and the ISO standard for digital, but that probably isn't the biggest problem with using any camera (not just digital cameras) to meter for another camera.

    The biggest problem is that cameras are systems themselves, and each part of the system can add variation.

    For instance, if there is a marked difference between the light transmission of the lens (the "T-stop") and the aperture of the lens (the f stop) then reading the f stop will introduce variation.

    If the shutter speeds vary in accuracy between the two cameras, and the reading obtained using the digital camera is adjusted or exposure, then the difference in the two shutters will introduce a variance.

    The exposure systems in digital cameras are designed to give good exposure with a system that is more like slide film than negative film. The ISO standard for film is oriented toward negative film. Differences in films often require us to develop separate and distinct EIs for films that have similar ISO ratings.

    It is no doubt possible to, through care and experience, develop a customized approach to making use of the information from a digital camera's meter (or any other camera's meter) to expose film in another camera, but the differences between the two systems do make it necessary to both be very careful about metering technique (such as using a standard focal length on a zoom lens) and to be very precise about using the right EI - customized to that particular combination of cameras, lenses and film.
    I agree with this post entirely Matt, very well written.
    Ben

  4. #34

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    Quote Originally Posted by noparking View Post
    For the record, the test above was done with the camera in aperture priority mode (f/16) and a Tiffen 40.5mm uv filter attached. I just re-did the test without the uv filter

    E-P1 Auto exposure mode
    -----------------------------
    E-P1 = 1/320 sec @f/10
    SBC-R ~ 1/320 sec @f/8
    SBC-I ~ 1/320 sec @f/9

    E-P1 Aperture priority mode
    -------------------------------
    E-P1 = 1/125 sec @f/16
    SBC-R = 1/125 sec @f/16 +1/3
    SBC-I = 1/125 sec @f/16 +1/3 (this time reflective and incident readings matched - I have no explanation why)
    The E-P1 gave the same readings in both modes.
    The SBC gave different readings first time and second time and the differerences are 2/3 and 1 stop. I think there is something wrong with the SBC readings.

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