Using the Zone System for Digital Photography

Discussion in 'Digital SLR' started by Gisle Hannemyr, Jan 15, 2007.

  1. I've just put up a note about my thoughts on adapting Ansel Adams'
    Zone System for digital photography on my website. Please see:

    http://hannemyr.com/photo/zonesystem.html

    Executive summary;
    After a lot of trial and (mostly) error, I found that the Zone
    System is just as useful with digital as it is with film. However,
    shooting digital is different from shooting film. This meant that
    some old rules of thumb (e.g. "expose for the shadows, develop
    for the highlights") had to be reformulated, and that some newer
    rules of thumb (e.g. Micahel Reichmann's "expose (to the)
    right") should not be adopted without understanding what they
    entails. I also found that standard tools, such as Photoshop ACR,
    is far from ideal for use with a Zone System-based digital
    workflow.

    I welcome your thought on the subject.
     
    Gisle Hannemyr, Jan 15, 2007
    #1
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  2. Gisle Hannemyr

    eawckyegcy Guest

    The "Zone System", as specified, is merely the chemical equivalent of
    PhotoSlop's curve tool. But PhotoSlop is a hell of a lot simpler
    though, in that you don't have to calibrate your media and development
    and the whole rest of the stuff: that's all been done for you by
    Canon. "Expose to the right" is utterly identical to "expose for the
    shadows, develop for the highlights": the laws of physics didn't
    suddenly change when digital cameras were invented.
     
    eawckyegcy, Jan 15, 2007
    #2
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  3. Gisle Hannemyr

    Matt Clara Guest

    Except you'll blow your highlights a hell of a lot faster with digital than
    film.
     
    Matt Clara, Jan 15, 2007
    #3
  4. Eh, no. Photshop's curve tool will let you tweak contrast and dynamic
    range - but that is just /one/ of things that the Zone System is
    supposed to handle.
    Eh, no. It is a (IMHO poor) approximation to "expose for the
    highlights".

    Did you actually read the article I linked to?
    ( http://hannemyr.com/photo/zonesystem.html )
     
    Gisle Hannemyr, Jan 15, 2007
    #4
  5. Gisle Hannemyr

    gowanoh Guest

    This is well written and well thought out.
    Digital capture and processing are far more flexible than chemical systems
    even if digital sensors as yet lack the dynamic range of negative film. As
    such most serious photographers develop a workflow that maximizes what they
    are trying to capture and print. The impact of software processing of
    digitized image information is such that the ways photographers think about
    their tools needs to change.
    Nevertheless the standard canard still applies that all serious
    photographers should familiarize themselves with the Zone system because it
    emphasizes thinking about lighting values in relation to the actual capture
    properties of the medium.
    Clearly the Zone system lends itself to static subjects and not every image
    can be analyzed in the required way prior to capture.
    The Zone system is essentially predicated on the idea that you want to
    produce one type of image, the long tone black and white print. The
    principles of the Zone system, aimed at capturing as much image information
    as possible, clearly have a place even in the brave new digital world
    although the long tone black and white print is not a major endpoint for
    most photographers.
    Photoshop and the ACR are not a rigid either/or proposition. There is
    nothing sacred about making adjustments within the converter or within
    Photoshop. Also the newest CS3 converter is far more flexible than the first
    generation CS converter. The conversion from digital color to black and
    white introduces many tonal variables independent of pure exposure issues.
    Again CS3 contains new tools for accomplishing this.
     
    gowanoh, Jan 15, 2007
    #5
  6. Gisle Hannemyr

    Alan Browne Guest

    1. The zone is B&W negative exposure, development and print oriented.
    2. Slide film is different (exp. for the highlights).
    3. Digital, for the most part, behaves like slide in this respect

    I'll give your webpage a good read, but I suspect for practical purposes
    that setting the highlights near the right edge of the histogram is as
    optimal as it will get unless I'm willing (and I am) to burn some
    highlights to get details in other areas of the image.

    Cheers,
    Alan.
     
    Alan Browne, Jan 16, 2007
    #6
  7. Accurate exposure is *much* easier with a good digital camera,
    because you don't need to assume it was right, you can *look* at
    the image immediately and determine (with a blink on
    overexposure LCD display or with a histogram) if it was correct.

    With many digital cameras it isn't hard to get within 1/3 of a
    stop every single time.
     
    Floyd L. Davidson, Jan 16, 2007
    #7
  8. Gisle Hannemyr

    Scott W Guest

    I think you might want to look at some of the numbers you are using, I
    get far more then a rangle of 50 to1 with jpeg images and I don't
    believe you can get close to 500 to 1 printing on any kind of paper.

    As for setting the proper exposure it is a pretty rare scene where when
    I expose to keep from blowing out the highlights I loose the shadow
    detail.

    Scott
     
    Scott W, Jan 16, 2007
    #8
  9. Hi Gisle,

    I'm reading your paper at present. Most of it I like but a couple of
    points I think are wrong:
    1. In section 2, Background, you say that both the dynamic range and
    tonal range are a function of the number of bits available. This seems
    only partly true. The dynamic range of a digital sensor is determined by
    its charge capacity (ie how full it can get before saturating or
    overflowing into adjacent pixels (blooming)), linearity of photon to
    electron conversion efficiency, any electronic gain circuitry,
    characteristics of the A/D converter, etc. Number of bits determines how
    finely you can resolve differences within this range, not the size of
    the range itself.
    2. In section 4, you confuse incident metering with reflected light
    metering, as the way cameras meter. Incident metering uses a handheld
    light meter with one of those white domes (not necessarily, but
    commonly) to measure the light that is actually incident to, ie hitting,
    the subject. Reflected light metering is what cameras use, since they
    read the light reflected from a scene, hence their tendency to make a
    black cat in a coal pile look like middle gray.

    Cheers,

    Wayne
     
    Wayne J. Cosshall, Jan 16, 2007
    #9
  10. I like your writing style well enough, and the layout is good.
    (You need to go over it with a spell checker. When I spell
    checked this article almost half the mistakes were in the quoted
    text! Given that I can't spell, your spelling must not be too
    good either!)

    A few points came up while reading.

    Limitations
    ...

    It is obvious that with JPEG, which uses 8 bits per channel,
    the dynamic range cannot exceed 1:256 (i.e. 8 EV).

    That would be true if and only if JPEG was using linear data,
    but it is gamma corrected. JPEG can have at least an 8 f/stop
    dynamic range. That is a "useful dynamic range", which is
    generally confined to the range that allows at least 8
    brightness values in the lowest f/stop of the range. (If we
    looked at it the way some people do the dynamic range of film,
    it would be more like 14 f/stops, but in the darkest level there
    would only be two levels and that generally would result in very
    unattractive posterization if actually used.)

    Doing it Digital -- First Approach

    With digital, we can no longer play around with
    development times. ...

    We can do *exactly* the same thing that happens when we play
    around with development times. Just change the ISO setting on
    the camera!

    The Troublesome Highlights

    With digital, highlights are a real problem. First,
    we never want overexposed highlights - not even in
    a single colour channel.

    Unlike film, which has great exposure latitude at
    the highlight end, digital is very unforgiving in
    the case of overexposure. Detail that is lost
    through overexposure, is clipped and lost
    forever. So why should we not place shadow detail
    in the lowest possible Zone ? that should in most
    cases contain our highlights well within safe
    limits?

    I realize that is the standard mantra, but it is a sugar
    coated version of truth. Detail lost with over exposing
    film is also lost forever. The fact is that pushing highlights
    up into the toe of the film's range will lose texture too,
    and just isn't the right way to make good photographs.

    The difference is that after you improperly expose film, you
    still have the option of changing development (to essentially
    change the ISO rating), where as with a digital camera you can't
    do that. Of course, with a digital camera you are 1) much more
    likely to have the tools built into the camera to determine that
    it is in fact over exposed, and 2) you have the option of
    adjusting the ISO setting and immediately making another
    exposure to get the same effect that film would give, or 3)
    changing the shutter or aperture settings and making another
    exposure.

    Obviously if the scene is a one time only, film has the
    advantage. But for any scene existing long enough to take
    multiple images, digital is more likely to result in a
    valid results.

    ... Both articles argue that in a 12-bit
    linear RAW file, 2048 levels (half the 4096 values
    allowed) will be use to record the f-stop with the
    brightest tones. It follows that if the values
    allocted for the brightest tones in the scene are
    wasted (i.e. your brightest highlights are -1 EV
    down the tonal scale), you are wasting half the
    luminance encoding levels your camera is able to
    record.

    The emphasis on "wasting half the luminance encoding levels" is
    poorly placed. It is a simple fact that in *most* images nearly
    all (1979 of the 2048) can be deleted without any visible
    change! (I.e., JPEG uses only 69 levels for that same f/stop.)

    It sounds good, but doesn't mean much. Nikon's NEF format can
    be used with and without compression, and with compression what
    they do is remove a significant number of brightness levels from
    the top three f/stops. For most images it has virtually no
    effect. Only for high key images where the texture of
    highlights is important does it have an effect (for example,
    wedding photography).

    Reichmann's recommendation, reflected in the title
    of the article, is that you should use your cameras
    histogram to evalute the light in the scene, and
    push exposure towards overexposure so that the
    histogram moves as far as possible to the right
    edge (without moving so far that highlights are
    blown as indicated by your camera's clipping
    warning). Doing so, Reichmann says, will improve
    the signal-to-noise ratio and therefore produce
    less noise and banding in the darker areas.

    The effect is, as others have stated... just about exactly the
    same as using the zone system with film. The difference is that
    you do both exposure and development at the click of the shutter
    release with digital, and don't make adjustment between those
    steps. That is to say the ISO setting is done before the
    shutter release with digital, but can be adjusted afterwards
    with film. In either case contrast and the black point are set
    in the process of printing (or display).

    The real difference is that with a digital camera we probably
    have a histogram and maybe a blink-on-overexposure display to
    help determine if the exposure is correct. Histograms are nice,
    but a blink-on-overexposure display is essential if there are
    light sources, or other highlights that are to allowed to be
    over exposed, in the scene.

    With film the same effect is accomplished by using a spotmeter.
    It requires an eye for scenes and light, knowing corrects for
    various lenses or accessories (bellows, extension tubes, etc) as
    well as the ability to provide uniform development of the film,
    based on the desired effects, every time. These skills are what
    makes a film photographer consistent. (Part of the reason many
    film photographers enjoy using film is simply that it *does*
    require certain skills, and because they have honed those
    skills it is certainly fun to use them! And more or less
    natural to dismiss digital as photography that doesn't require
    skills...)
     
    Floyd L. Davidson, Jan 16, 2007
    #10
  11. Thank you for pointing this out. I think you are correct. I need
    to think more carefully about how I describe this. I will revise
    the article on this point ASAP.
    Yes. This one is a blooper. I've changed the article and hope
    I've got it the right way around now. Thank you for the correction.
     
    Gisle Hannemyr, Jan 16, 2007
    #11
  12. Pleasure, Gisle. It is very easy to make a mistake or two in a long
    article. I know I do it.

    Cheers,

    Wayne
     
    Wayne J. Cosshall, Jan 16, 2007
    #12
  13. Gisle Hannemyr

    Ken Lucke Guest

    There's a Photoshop plugin that already does this automatically - it's
    called Ozone (current version is 2.0):

    http://www.pluginz.com/product/10254?from=rlist

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Jan 16, 2007
    #13
  14. Executive summary;
    Digital seems to be more lenient. If you want to use the zone system,
    check out LightZone. You can get a free 30-day trial. For me it was
    like returning to the darkroom but a much modernized version.
     
    Robert Peirce, Jan 17, 2007
    #14
  15. Gisle Hannemyr

    Paul J Gans Guest

    I'd say it this way: "With many digital cameras it isn't hard to get
    within 1/3 of stop of where you want it every single time."

    The problem of course is knowing where you want it. That's
    what distinguishes the good photographers from folks like me.
     
    Paul J Gans, Jan 19, 2007
    #15
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