SOT: "Zone System" of exposure.

farss wrote on 4/9/2010, 5:18 PM
Maybe everyone else knows about this and uses it daily. I've grappled with finding this "language" until now. What I'm talking about is this Zone System. What was such a revelation is the it goes directly back to what we see in the real world rather than arbitary numbers and words.
As there's a lot of material in that Wiki, what I'm specifically referring to is half way down the page, the chart starting with "Adams (1981, 60) described the zone scale and its relationship to typical scene elements"

Of course our digital video cameras are incapable of anything like the dynamic range of negative film and setting exposure for the most important element in a scene and letting eveything else fall where it may could give horrid results. That's a given however what I find useful is we have a "language". Instead of talking about "blacks" we have a set of zones that give us a common language that we can all easily relate to.

Bob.

Comments

malowz wrote on 4/10/2010, 3:15 AM
i "find out" this system a while ago, wile researching photography.

i found it amazing. for photo, its great, but as i use "strobist" style, only is useful with continuous light. so, his is very good for video also.

as cameras do not have a "exposure" level, the histogram is the only thing to use. after analyzing, you know the "places" of histogram to know your exposure.

but the problem is, most mid-level cameras do not have a fixed aperture, so when you zoom, you get a darker image. after a wile, you know how to "compensate" ;)
musicvid10 wrote on 4/10/2010, 7:59 AM
I learned the zone system from a book when I was twelve years old. It became intuitive over time, and I highly recommend it (how many people do you see checking zones with an EV meter these days?)

Here is a nifty article I found about applying zone theory to video:
http://www.cybercollege.com/zone.htm

(Note that the article deals in IRE units, not RGB).
farss wrote on 4/10/2010, 2:55 PM
What I was interested in was not the system in terms of setting exposure at all. I see using the zone numbers as a way to communicate parts of the tonal range that are easily understood.
For example conside the following statement:
A lot of what I shoot is in zone 0 to zone 5 and I want to get solid noise free blacks from zone 0.
I think I've now effectively communicated the issue. No, I'm not asking for an answer, I've pretty well worked it out although any input appreciated. What I was hoping to highlight was using the zone numbers to communicate what we're talking about.

Bob.
musicvid10 wrote on 4/10/2010, 3:13 PM
"I see using the zone numbers as a way to communicate parts of the tonal range that are easily understood."

Yes, you are correct, as a communication syntax it is entirely useful and would benefit a lot of videographers if they would adopt it.

As part of self-training and recreation, small groups of us would go out on shooting expeditions, try to predict zone numbers visually, bracket a few shots based on our predictions, then start running around with our spot meters and shoot another series based on measured data. A few got really good at predicting exposures visually that way.

Needless to say, the jargon used was quite incomprehensible to the uninitiated, but completely understood by fellow zone system enthusiasts. The advantage over digital photography is that we could control tonal range in the developing stage, often by very long developing times in very weak developer solutions.
arenel wrote on 4/11/2010, 3:04 PM
Years ago I took a seminar on lighting for video for cinematographers. The key element of the presentation as I remember, was determining the ASA/ISO of your camera. ( I mention ASA to give you an idea of how long ago it was.) Looking at your waveform of the scene or card you would corralate the waveform steps with your meter and f/T stops on the lens. You could light the scene to place elements in zones that you felt appropriate artistically using your lightmeter. With scene control the gamma curve of a scene can be adjusted to some degree. If your lens doesn't do f-stops it is kind of hard to make the system work in video.

Ralph