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class="style7"> Zone System Headache - Does Anyone Have A Pill ?

>Published : 11th October 2007

>Hi there,

>This is a first post from a newbie trying to grasp some basics regarding the Zone system of exposure. If anyone can help me I'd really appreciate it - just please be gentle!

>I have read quite a few explanations and discussions recently, but one concept seems to remain unexplained. It is this: Is the Zone system based around a 'subjective' set of brightness values or 'relative' values as judged in each different setups ?

>For example; is a zone IV always a zone IV in say both a midday-sunlit exterior and night-time car interior? And in the case of the latter would say on-coming car headlights qualify as zone IIX - IX ?

>I can see the sense in the accurate placement of a 'central' zone V (18% grey) and in the case of a wide-latitude stock like B+W this will allow for the accurate renditions of about four zones above and below V. But does this mean that when applying the system to video (eg my own XL1s) that if I expose my Caucasian skin-tones accurately at zone VI that I must make sure that any further highlights should fall in only about one-and-a-half zones over and dark shadows three zones under zone V. (a 5 stop range ?)

>I apologize if my questions sounds dumb and obvious but I really want to grasp the basics of this great system so that I can apply it accurately.

>Thanks in advance for throwing further light on this issue.

Tim Cromar

London, UK.
Studying to expose and light for film and video.


>I usually think of the zone values as relative values, from deepest black to whitest white. Maybe this discussion of film sensitometry on the Kodak website will help show the objective basis of the zone system:

>http://www.kodak.com/US/en/motion/support/h1/structure.shtml

>Changing exposure on a negative film just moves the scale up and down the sensitometric curve -- the relative relationships between the tone values remains constant if you are on the "straight-line" portion of the characteristic curve. Lighting contrast and film contrast, not lighting intensity or film exposure, normally changes the relationships. The value of the zone system is that it helps predict and control what changes in exposure and processing (contrast) will have in the final image when you are NOT on a linear portion of the film's characteristic.

>A related control tool is the Laboratory Aim Density (LAD) control method, which I developed:

http://www.kodak.com/US/en/motion/support/lad.jhtml?id=0.1.4.15.8.6

&lc=en

>John Pytlak
Eastman Kodak Company


>Hi Tim,

>This is basics so you shouldn't be worried.

>The zone system is great precisely because z7 is always z7 and z3 is always z3.

>It's an absolute system of reflected values, of course once you start altering the processing and post then the values change but z6 is always one stop brighter than z5 and one stop darker than z7.

>It's really worth learning this system, and I'd recommend "The Negative" by Ansel Adams as your basic starting point.

>I tried for a while to use the zone system to predict exactly how a finished film would look, I took it to the extreme on
/SEGACYBR%20qt.HTM where I gave my gaffer a set of drawings of the set with zone values, in stops, drawn on it and told him to light it to the numbers.

>The great thing is that it worked and the finished job is exactly what came out of that!

>--

>Cheers

>Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


>Thank you John for the prompt reply.

>I think I am probably still a little 'junior' for that info but will certainly check out your method also!

>Best,

>Tim Cromar
London, UK.
Studying to expose and light for film and video.


>Hi Geoff,

>Thank-you for your fast reply as well. I'm digesting your advice, and in doing so I guess (as always) it raises a further question. If indeed z6 is always z6 whether it be down a coal mine or in a sunlit meadow then can that zone have a 'fixed' EV or ft-Candle level - surely not ?

>Isn't it in fact the case that every time a set-up changes, zoneV is 'reset' to whatever is 'chosen' as the mid tone of the specific shot and cannot be categorized or fixed at say 55IRE ? Or am I on the wrong track again...? :-/

>I guess I will be heading to my local bookshop for a copy of 'The Negative' by Mr Adams and all will become clear in time.

>Thanks again for your advice and for sharing your reel with a practical example of the zone system still in action!

>Best,

>Tim Cromar
UK
Studying to expose and light for film and video.


>I think zones should be thinked over the brightness of the copy. Not as a absolute value of lightness. So, forget about that of 10 zones equally distributed in the, eh... mmmm, 10 stops ratio? Is it a joke? 10 stops? No, no. Think in this: Zone I is the umbral of light the film can perceive. It is the point of the HD curve where the sensitivity is measured. Zone IX is (as the ISO standard say) the 90% of the maximum density of the film (Or the print, or the screen, or the page of the book where you are going to print the image).

>There is a great difference between think in zones for the scene and think in zones for the print. In the print, you cannot achieve a reflectance greater than 1, so if the zones are distributed equally and have 1 stops of increment, then it is impossible to get a zone greater than 7,3. So zones should not be distributed uniformly over the print, but in the scene you do not have any frontier. You always can find a scene with specular reflections, which have a reflectance greater than 1, and you always can find a non uniform illumination. So where in the scene is the "zone IX"?

>Think in this : there is two kinds of "tones" in the scene: detail tones and accent tones. Details are those from zone I to zone IX. Accent are those lower than 1 and greater than IX But what is "Zone I". If you take the Lightness of the media (or the scene) the Zone IX is the lightness greater than L*=96 and zone I is the lightness L*=6.

>--
/*_______________________*/
"Creer es mucho más cómodo que dudar"
Joan Fontcuberta

>Paco Rosso
www.pacorosso.com
Luz, colour, fotografía.


class="style11">>>If indeed z6 is always z6 whether it be down a coal mine or in a sunlit >>meadow then can that zone have a 'fixed' EV or ft-Candle level - surely >>not ?

>Absolutely not.

>What any zone value is ... is the level of brightness that it is in the final image.

>YOU decide where to put an area, if you underexpose my face by a stop then it will fall in z5, this is because an average Caucasian face is z6. Equally if you overexpose me by a stop I'd be in z7.

>What you need to be learning is what are relative brightness levels and how do you translate those in to a finished image.

>The photographs in "The Negative" illustrate this very clearly.

>--

>Cheers

>Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


>Tim Cromar wrote:

class="style11">>>I guess I will be heading to my local bookshop for a copy of 'The >>Negative' by Mr Adams and all will become clear in time.

>Ansel Adams is a good choice alternatively have a look at "Beyond the Zone System" from Phil Davis.

>Zone System aficionado.

>Regards

>Emmanuel, Munich

Assistant Caméra - Camera Assistant - Kamera Assistent
BVK- European based
Mobil# Munich +491608036889 - London +447910034443

(Please use German number)
cml-listmum


>Hi Art,

>Thanks so much for casting some more light on this subject - I'm positively glowing now!

>Best,

>Tim Cromar
UK
Studying to expose and light for film and video.


>Hi Emmanuel,

>Thanks for the title - I will check it out also!

>Best,

>Tim Cromar
UK


>Hi Paco,

>Very interesting also - thanks for your advice. I must go and think and experiment now...

>Best,

>Tim Cromar
UK


>Why we have 10 zones?

>We have ten zones because the original work of Davenport, base of the study of Adams, were realized with a Weston Master II spotometer, who has the screen divided in 10 parts. If the photometer would have 6 parts, we now should be using a zone system with 6 zones...

>10 zones is merely a curiosity, not a reality.

class="style11">>>You'll need to adapt the Zone System to your specific camera or film >>stock

>Paco Rosso
Luz-Color-Fotografía
http://pacorosso.blogspot.com


class="style11">>>If indeed z6 is always z6 whether it be down a coal mine or in a sunlit >>meadow then can that zone have a 'fixed' EV or ft-Candle level - surely >>not ?

>A zone doesn't have a fixed amount of FC. It is a relative value, and tells you how bright or dark objects will look like compared to each other, and in order to measure this well, you need to do a spot-measurement.

class="style11">>>Isn't it in fact the case that every time a set-up changes, zoneV is 'reset' >>to whatever is 'chosen' as the mid tone of the specific shot and cannot >>be categorized or fixed at say 55IRE ? Or am I on the wrong track >>again...?

>Zone V will always be at your said 55IRE, but sometimes you need 100FC of light to reach that zone V, sometimes you need 10,000FC.

>cheers

>Martin Heffels
/filmmaker/DP/editor/
Maastricht, the Netherlands