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Thread: Picker on exposure

  1. #21

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    Re: Picker on exposure

    Quote Originally Posted by Leigh View Post
    I think the "key stop" thing was based on the idea that there's one optimum aperture for any given lens
    Hi Leigh,

    I found it... "Key Shutter Speed," discussed in Newsletter #24.

    The f/stop is: f/22.

    Then you find the key shutter speed. Now never go over it and you will never use too fast a shutter speed (so the hare-brain logic goes).

    Now I don't mean to sound critical of him, I enjoy reading his works and asking myself "is he right or is he wrong?" Can't do that with Donald Knuth or Ansel Adams.

  2. #22
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: Picker on exposure

    ???

    What shutter speed is "too fast"???

    - Leigh

  3. #23

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    Re: Picker on exposure

    Quote Originally Posted by Leigh View Post
    ???

    What shutter speed is "too fast"???

    - Leigh
    This is the magic of Picker's brain.

    You test for the brightest possible day and use all your upper shutter speeds at f/22.

    Then develop normally and print a proper proof.

    The shot that comes out correct is your "Key" shutter speed. Set your camera at f/22 and that "Key" speed when you setup.

    Never use a faster shutter speed than that because you just proved that that is the fastest shutter speed you could ever use.

  4. #24

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    Re: Picker on exposure

    Basing the exposure on highlights rather than shadows is, as Peter explains very well, a decent system for roll film and images made under different lighting conditions because it's based on an average five-stop scene. But with sheet film it seems to me an unnecessarily loose system. Why assume that each image was made in scenes with a five (or less) stop range, when we know that isn't always the case and when there is a system (expose for the shadows, process for the highlights) that will work well even when the range exceeds five stops?
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  5. #25

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    Re: Picker on exposure

    Quote Originally Posted by Brian Ellis View Post
    Basing the exposure on highlights rather than shadows is, as Peter explains very well, a decent system for roll film and images made under different lighting conditions because it's based on an average five-stop scene. But with sheet film it seems to me an unnecessarily loose system. Why assume that each image was made in scenes with a five (or less) stop range, when we know that isn't always the case and when there is a system (expose for the shadows, process for the highlights) that will work well even when the range exceeds five stops?
    It works just as well for sheet film Brian.

  6. #26
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    Re: Picker on exposure

    I understand trying to get good printable negatives on roll film or standard-developed sheet film. What I'm still not understanding is, why it's better to base exposure off the highlights than the shadows.

    There are two ends of the film--the toe and shoulder. If you meter the shadows and place them against the toe, you will have maximum latitude from there upward. You are making sure that you just barely catch the shadows, and you are hoping the highlights don't run off the film and block up (not likely for vast majority of scenes).

    If you meter the highlights of the scene, and place them right against the shoulder, you will have maximum latitude from there downward. In that case you are ensuring that your highlights are just barely not blown out, and hoping that your shadows don't run off the bottom of the film. My question is how you determine what to call the "shoulder". In my estimation, modern films do not have a distinct shoulder anywhere near normal density ranges, so if you literally place the highlights up against the shoulder of the film you will have a ridiculously dense negative. It does not seem efficient. If you don't want such a dense negative and you artificially decide to place the highlights onto some 'zone', which zone you have arbitrarily decided to be a certain number of stops from the toe, well, I just don't see why you would do this or why it has any advantage over placing a shadow reading at the toe.
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  7. #27
    Peter De Smidt's Avatar
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    Re: Picker on exposure

    Bruce Barnbaum advocates doing standard zone system film tests and then halving the discovered EI. Les Mclean advocates placing the lowest detailed shadow on Zone IV. Can you see how this is equivalent? Both are advising giving more exposure than standard ZS practice, as this moves the shadows up on off of the toe of the film, which gives them greater separation.

    So, if you want good shadow separation, place them so they fall on a steeper part of the characteristic HD curve.

    Picker is giving very similar advice. If you place the detailed highlights at VIII, you will often be giving more exposure than you would be by placing detailed shadows on zone III. He didn't want to "just barely catch the shadows."

    Nor did he want to create a super dense negative. With roll film, he wanted a standard 5-stop scene to print well on grade III paper. He did tests to find out what negative densities would do this, and that is how he figured out how to place Zone VIII. In particular, he figured out a minimum time to get a visually maximum black on grade III paper through an unexposed but processed piece of film. That gave him his exposure time using the enlarger for the subsequent tests. He'd then put a piece of grade III paper in the easel, and a candidate Zone VIII negative in the enlarger, and he exposed the paper for the discovered time. If it made a very light tone just a bit darker than paper white, then he knew that he had discovered his proper development time. If it made a darker tone, then he knew he had to develop a bit more, and if it was paper white, then he knew that he had to develop less. After doing this, I'm sure he used his densitometer to read the resulting densities.

    So, with a 5 stop scene his exposure recommendation exactly matched traditional zone practice, and so it's a little weird for people advocating that method to criticize him. In this case, placing the detailed shadows on III or the detailed highlights on VIII gives the equivalent exposure.

    With a 4 stop scene, he was advocating giving more exposure than standard, ala Bruce Barnbaum and Les McLean. And so I think that people criticizing him for not valuing shadow detail are off base.

    He wasn't a fan of minus development, and he generally avoided scene of a much higher subject brightness range than 5 stops.
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
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  8. #28
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Exclamation Re: Picker on exposure

    Quote Originally Posted by Bill Burk View Post
    The f/stop is: f/22.
    Then you find the key shutter speed.Now never go over it and you will never use too fast a shutter speed...
    This is absolute nonsense.

    Shutter speed and aperture are two of the basic creative options in photography.

    To say you should always shoot at f/22 or never shoot faster than x is stupid.

    Fred understood very well a fundamental aspect of marketing in the USofA:
    You don't build a name (i.e. $$$) for yourself by supporting the status quo.
    You make bucks by presenting different ideas, then nurturing a mindless following who will shout your name to the heavens and proclaim you their savior.

    As P. T. Barnum observed: "There's a sucker born every minute."

    - Leigh

  9. #29
    Peter De Smidt's Avatar
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    Re: Picker on exposure

    I never remember Fred saying to only shoot at F22. Perhaps it's not fair to accuse him of nonsense when it's unclear what he advocated?
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer, Nothing You Don't Already Know

  10. #30

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    Re: Picker on exposure

    Quote Originally Posted by D. Bryant View Post
    It works just as well for sheet film Brian.
    I know it can be used with sheet film and will work in the right circumstances. But as I said in my previous message, it seems unnecessarily loose or imprecise with sheet film and there are other, better IMHO, alternatives with sheet film that aren't available with roll film.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

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