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  1. #11

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    Quote Originally Posted by Stephen Benskin View Post
    Let's not forget exposure meters. People talk about them seeing 12%, or 18%, or Zone V.
    Ok now I think I see where you're going.

  2. #12
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    Quote Originally Posted by Michael R 1974 View Post
    Chan Tran: That's all fairly obvious so I'm still suspicious. Underlying all the variables is the usual question of whether or not the various image exposures at the film plane based on the metering and camera setting will generate the expected film densities (ie the first transition in the tone reproduction diagrams), but I don't think that's what Stephen is getting at.
    That is what I'm getting at. It should be obvious, but how many people are comfortable with it. In camera testing, such as the Zone System method, use the exposure meter for calibrating the film speed, yet few can define what the meter is actually doing or what the exposure at the film plane should be.
    Last edited by Stephen Benskin; 05-09-2013 at 11:03 AM. Click to view previous post history.

  3. #13

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    Well, I'll admit, for example, the section in Henry's book on meters is fairly tough for me to get through every time.

  4. #14
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    I have a couple simple questions.

    Is it just that the meter wants to put the same amount of light on the film as sensitometric testing would put on the film?

    Then the meter has the extra work to try to back out the optics of the meter and factor in the optics of the camera and estimate the camera flare. (while an in-camera meter is excused from some of that work)?

  5. #15
    Stephen Benskin's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    Well, I'll admit, for example, the section in Henry's book on meters is fairly tough for me to get through every time.
    Henry was somewhat non-specific in that section.

  6. #16
    Stephen Benskin's Avatar
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    Quote Originally Posted by Bill Burk View Post
    I have a couple simple questions.

    Is it just that the meter wants to put the same amount of light on the film as sensitometric testing would put on the film?
    That's bascially how the two are related.


    Then the meter has the extra work to try to back out the optics of the meter and factor in the optics of the camera and estimate the camera flare. (while an in-camera meter is excused from some of that work)?
    Yes, hand held exposure meters have to estimate the value of q, while in camera meters measure the actual luminance passing through the optical system.

  7. #17

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    Quote Originally Posted by Stephen Benskin View Post
    Henry was somewhat non-specific in that section.
    Why do you say that? It gets into quite a bit of detail on calibration, flare etc.

  8. #18
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    Quote Originally Posted by Michael R 1974 View Post
    Why do you say that? It gets into quite a bit of detail on calibration, flare etc.
    Not very specific for my taste, and while we're talking about it, not very accurate either.

  9. #19

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    In any case it doesn't matter much to me since there is not much I can do about it anyway. I always get a laugh out of the meter modifications. I'll get right on that as soon as Leica builds me a precision 4x5.

  10. #20
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    Quote Originally Posted by Michael R 1974 View Post
    In any case it doesn't matter much to me since there is not much I can do about it anyway. I always get a laugh out of the meter modifications. I'll get right on that as soon as Leica builds me a precision 4x5.
    Take a look at his flare graph. He starts it at 0.10 over Fb+f and has the amount of flare based from that point, when it is actually based off a stop below. A flare factor of 2 will not double the exposure at 0.10. His exposure testing also uses Zones and stopping down 4 stops.

    What about the technique of shooting a step tablet with a camera, whether it is inside like with Shaffer's method or outside like WBM? The camera is the exposing device and the exposure meter determines the exposure. Wouldn't it be beneficial to understand what the film plane exposure should be (Hg)?

    Let's say we are testing a 125 speed film. What should the exposure be at the speed point? What should the exposure be at the metered exposure point? What is the difference between the speed point constant and the exposure constant?
    Last edited by Stephen Benskin; 05-09-2013 at 07:02 PM. Click to view previous post history.

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