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Thread: In The Zone.......or not?

  1. #1
    Member JGH's Avatar
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    Question In The Zone.......or not?

    Hi all,
    Over the last few months i have ben experimenting with the zone system and have been fairly confident that i was getting the correct results.
    I have been zeroing my meter on a particular tone in the image which would equal zone V and then adding or subtracting by whatever stops necassary to place that tone in the desired zone.
    Everything is fine when i do that and if i have placed it correctly i get the desired effect. The problem i now have is i cannot seem to relate my on camera histogram to the zone system. let me explain. If i add 2 stops to a tone that i zeroed to zone 5 (centre of the histogram) then that tone becomes a zone VII but when i look at the histogram on the camera it has nearly reached the right hand side (this is fine as it has not blown out). Now IF the histogram on the camera is representing the entire zone system (from 0 through to X) wouldnt the histogram only be reaching 2/3rds to 3/4 of the way along the right hand side?
    Checking the LAB luminosity numbers in PS CS5 for the modified zone shows that it is around 85 - 92ish when technically it should be in the 70's.

    I have got to the point were i have confused myself because i am thinking to much and need some help from people who can shed some light on what i have overlooked.

    I hope there is someone out there with the patients to help me with this because even though i am getting good exposures it would help to understand why the histogram goes to zone 8 or 9 (sometimes 10) when i only dialled in 2 stops of compensation.
    I think what i have said makes sense? Please help !!!

    Thanks

    J

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    Senior Member stephengilbert's Avatar
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    Re: In The Zone.......or not?

    J,

    You might want to post this question in the Large Format section as well.

    Steve

  3. #3
    richard.L
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    Re: In The Zone.......or not?

    maybe think about:
    http://www.lightcrafts.com/lightzone/

    or

    http://www.digitalfilmtools.com/ozone/

    by the way UWE S on this board has an article here

    http://www.outbackphoto.com/artofraw/raw_26/essay.html

    // I believe he was a consultant to OZone product /
    Last edited by richard.L; 3rd August 2011 at 09:42. Reason: update uwe info+link

  4. #4
    Member JGH's Avatar
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    Re: In The Zone.......or not?

    Thanks for the links Richard. I started out with lightzone before i got C5 and LR. Its a great program for analyzing the zones in an image but i found the other areas of the software a little clunky for me.
    OZone 2.5.7 is the main reason i have ventured on this quest as it was the program that first showed me the issue with the zones. I will check out the article though thanks.

    Through further reading i stumbled upon an explanation that may be a solution to my problem. It was something along the lines of digital cameras do not require all the zones in the zone system as zones 0 & 1 and zones 9 & 10 were for the paper printing process and a digital camera effectivly sees zone 2 as pure black and zone 8 as pure white which leaves zones 3 to 7. Thats 5 stops !!! i know digital cameras can see more than that so that it a little confusing however 5 stops from end to end does seem to ring true with both my cameras because if when placing a zone i under or over expose by 2 stops the histogram will just sit before the left or right edges.
    So maybe the histogram on a camera only shows these 5 stop values?
    I dont know this for sure and this is just what i read. I was testing some more this evening and it seems to be about correct. Any more than 2 stops either way blows the highlight or shadows. I can live with that. I should just be happy im getting good exposures and not be so anal about all the numbers !!!!

    J

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    Re: In The Zone.......or not?

    I am of opinion that the above and in your related post so far is largely incorrect. It sounds as if you are attempting to apply a simplified zone system for digital, but such do not exist. For slide film a simplified zone system told you that for slides +2.5 was the brightest tone you could capture and -2.5 stop darkest. Same as the zone system need be applied different for different film (slide film, b&w film vs. polaroid), it needs to be applied based on the character and response of the sensor that is in your digital camera. Digital is essentially a different type of emulsion and different sensors are like different films essentially (different DR, response etc).

    I recommend following books:
    - The Negative by Ansel Adams
    - The Practical Zone System for Film and Digital Photography by Chris Johnson

    The first is the best resource explaining the non simplified zone system relating to b&w film, or which can be any media, and of how Ansel descibed as zone I, II etc related to stops for b&w, including the fundamental basics of the zone system. The last is the only book that well describe how it relates and can be applied to digital (one chapter).

    First you need to understand how a sensor fills up the sensor buckets and why there is talk of exposing to the right, please refer to here http://www.luminous-landscape.com/tu...se-right.shtml. This is because unlike film a sensor is a linear device, which explain the results you received when directly applying stops similar like you do on film.

    Next you may wish to read following article http://www.luminous-landscape.com/tu...exposure.shtml and the discussion on LuLa in which I and others have jumped in regarding to spot metering and ETTR, http://www.luminous-landscape.com/fo...?topic=56309.0

    In essence for digital you wish to assure that the brightest in your scene renders within the capability of your sensor (is not blown out), and that you do get detail and not too much noise in other end. Thus the critical is to spot meter for a zone VIII, IX or X, however that does not mean that your zone V is fixed since you can move that in post. Likewise you can recover lost data. Thus you should in essence make a test for what is the brightest above mid tone that you can get out of your sensor (no loss data, zone VIII, IX) after recover in post.

    Depending on the image quality within the DR of your camera and pending on the scene I would argue that there may or may not be a need to apply ETTR and spot metering. It depends on what we shoot and the DR, as it also did with film.

    Regards
    Anders

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    Senior Member Lars's Avatar
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    Re: In The Zone.......or not?

    I'm with Anders, ETTR is the way to go. Keep in mind that that Zone system was created in the absence of a histogram, and for the purpose of using the nonlinear properties of film and paper to control hardness, as much as exposure, in the wet darkroom. Shooting digital, we can control contrast in post, and the instant histogram makes a spotmeter almost redundant.

    If you still want to think about the camera histogram in terms of zones, consider this: What is the scale of the histogram? It's certainly not logarithmic, so zones will not be evenly spaced. A qualified guess is that it's gamma-coded using the 2.2 gamma of sRGB and AdobeRGB colorspaces.

    Gamma 2.2 places the middle of the scale as 21%, slightly over the 18% gray standard commonly used but acceptable for a midtone level. This also means that you have 2.2 steps of latitude to the right side of the histogram, meaning it clips at zone 7.2, so if you want to find zone VIII, IX or X then you are looking in vain. Usually the camera handles a bit more than 7.2 as it uses the extra highlight range of the sensor to avoid clipping.

    What all this means is that you basically have the same DR as slide film on the highlight side. In the shadows you have a lot more though.

    Just about now you should start asking yourself "OK, why am I considering using the zone system again?" All you need to think about is where to place the highlights and midtones, and let the shadows fall where they may.

    Put your effort into getting a good feel for metering modes and manual exposure instead, together with a close eye on the histogram.
    Monochrome: http://mochro.com

  7. #7
    Shelby Lewis
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    Re: In The Zone.......or not?

    I definitely agree with Anders... but don't let the nature of sensors (vs. film) keep you from using the artistic merits of the zone system to some extent.

    While I can't find the time (nor a way) to find a digital zone system "analogue" for myself, I am in the process of testing my sensor such that I know pretty precisely where I exceed it's limits on the highlight side... say zone IX for me. Armed with a spot meter that is calibrated to my sensor, I am able to place the highest non-specular "zone" where I want to... and then confirm with the same meter whether the scene exceeds my sensor's capabilities at the shadow end. The lower zones will fall where they will... but, hey, development post-capture (in the film days) could help move the zones around a bit if needed. Digital post-processing is similar in that regard.

    For me, this is less about finding a way to place each zone and more about a working method that takes the zone system as a place of departure while still keeping some of its artistic merits in play.

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    Re: In The Zone.......or not?

    Quote Originally Posted by Shelby Lewis View Post
    Armed with a spot meter that is calibrated to my sensor, I am able to place the highest non-specular "zone" where I want to... and then confirm with the same meter whether the scene exceeds my sensor's capabilities at the shadow end. The lower zones will fall where they will... but, hey, development post-capture (in the film days) could help move the zones around a bit if needed. Digital post-processing is similar in that regard.

    For me, this is less about finding a way to place each zone and more about a working method that takes the zone system as a place of departure while still keeping some of its artistic merits in play.
    100% exact, this is application of zone system for digital, as in applied at capture stage to control what useable data we get for post.

    It is not used to assign specific zone at capture to its stage in post. Nor did Ansel Adams since he used expansion and compression techniques in developing, per say he did a simplification of the much more adjustments what we nowdays do in post.

    Thus it also differs from the simplified zone system applied for e.g. slide film, since for slide film there was no change of contrast or zones between capture and the processed slides.

  9. #9
    Shelby Lewis
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    Re: In The Zone.......or not?

    Quote Originally Posted by Anders_HK View Post
    100% exact, this is application of zone system for digital, as in applied at capture stage to control what useable data we get for post.
    Thanks!

    BTW... this subject matter is partially why I asked the question in the MF forum about getting as "raw" (not literally) an image, tethered, into my laptop as is possible... as another means to check how far I can push the highlight zone before losing detail (to confirm my meter/camera calibration).

    Cool discussion everyone.

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    Re: In The Zone.......or not?

    something to bear in mind is that the histogram is sort of blind, compared to a spot meter that can actually meter a particular visible portion of the image. I would compare the histogram to incident metering

  11. #11
    Super Duper
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    Re: In The Zone.......or not?

    The answer is simple, the gamma or contrast index of the film and sensor are different. It has nothing to do with the linearity of the film/sensor response. Digital sensor do not have a latitude of negative films and so the gamma is higher which mean a one stop change will move the resulting tone into a higher or lower zone than you anticipate. If you want to use a digital camera and the zone system, and there is not technical reason you cannot, then you are going to have to redefine the zone scale for the sensor.

    The other side of this is since you can see your histogram and image after you take the picture, why do you want to use the Zone System? Film photographers did not have this option and so the Zone System was a way to control and anticipate results at any one scene.

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    Re: In The Zone.......or not?

    my point was that while the histo will show overall exposure, it will not relate to particular areas of the image, should you be concerned about exact exposure in those areas

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