(Photo is from the Wildcat Trail in Monument Valley illustrating use of the Zone System)
What follows is my ramblings on the Zone System. My goal is to present it as easily as I can but should not be taken as an end-all on the subject but rather as a leaping board to encourage more discussion on proper exposure technique.
Back in the before time, the long long ago, man shot on film. He did so out of need, he did so for survival...
Sorry that was stupid.
O.K. The Zone System.
"What is it, Chris?"
imgur.com/JfuepMb.gif
Stupid again...
Simply put, the Zone System is a technique for figuring out the best exposure with the final product in mind.
Ansel Adams and Fred Archer came up with the technique. And though originally intended to aid black and white film photographers in visualizing the final print when photographing a scene/subject, it can still be applied to today's photographic process.
In today's world it's so easy to forget the deliberateness of the photographic process - I pick up my iPhone activating the motion sensor which turns on the screen, I swipe to the right and hit the button. I've got a photo in less than two heartbeats.
In the long long ago, I'm talking view camera times, it might take you 30 minutes before you were ready to snap a photo. And you still had to develop the film and print the image before you had something to share with others.
No wonder you see blogs/articles stating that more photos are taken today in the time it takes you to microwave a bowl of Ramen noodles than during the entire 19th century.
I'm not saying you need to be a snail but "slow and steady wins the race". Quality over quantity, man. We don't upload 30 photos to Instagram at once, we pick and choose the best ones. Let's take that approach at the beginning as well...
You found your subject. It's this hot blonde sitting alone in the park. (imgur.com/mzUcFJ1.png)
"Excuse me, miss. May I take your photo?"
She sticks her tongue out at you. She's panting, she's drooling... obviously flattered by the attention you're giving her.
Aw, her eyes, man. They're pulling you in. The way the summer sun halos her enchanting golden hair... Ugh! Take the shot!
Shit. I'm in Manual mode and I don't have time to take a second photo before the moment is gone! What do I do, Chris? Flip it to Tv mode, crank up the shutter speed, flip on Autofocus and smash dat button.
You just shot your subject in Zone V - middle gray. It probably wasn't ideal for a Golden Retriever but you accurately recorded the exposure giving you lots of leeway in post to brighten up the subject without clipping the important highlights in-camera. That high shutter speed was to combat the fast movements of the dog and you got a shallower depth-of-field as an added bonus. Bitches love DOF.
But Chris I'm shooting expired slide film on an old Agfa Paramat with a broken selenium light meterrrr...!
Well you're a freak and I cannot help you. Go on Ebay, buy a Canon EOS 630 for $15, maybe find one with a 50mm lens for $30 more or buy that cheap one on Amazon, the 2CR5 battery for ~$7 and some cheap yet effective Fuji film from Walmart. You're back in the game.
But Chris I'm shooting a pinhole coffee can... Stop. Just stop.
We're not getting anywhere with that.
The Zone System has a scale from Zone 0 to Zone X. Zero being pure black - no recorded detail. Ten being pure white - light bulbs, the sun, the sun's reflection off your car, your dad's waxed head, etc. etc.
Each zone on the scale relates exactly to one-stop exposure intervals.
If your light meter/center-weighted in-camera meter indicates the normal exposure (Zone V) is 1/125 at f/8 (@ iso 100) then the sequence of exposures could be as follows:
Zone X: 1/30 @ f/2.8 Zone IX: 1/30 @ f/4 Zone VIII: 1/30 @ f/5.6 Zone VII: 1/30 @ f/8 Zone VI: 1/60 @ f/8 Zone V: 1/125 @ f/8 Zone IV: 1/250 @ f/8 Zone III: 1/500 @ f/8 Zone II: 1/500 @ f/11 Zone I: 1/1000 @ f/11 Zone 0: 1/1000 @ f/16
I changed not only the shutter speed but also the f-number to illustrate how you can choose the values based upon your other needs like shooting handheld, combating reciprocity failure, or diffraction.
Zone II is the darkest part of the image in which slight detail is recorded.
Zone VIII is is the brightest part of the image in which slight detail is recorded.
Zones I and IX have slight tone but no texture.
Zones 0 and X are pure black and pure white with no other information recorded.
Example: When you meter for snow it's gonna tell you an exposure that's probably three stops off. Snow is white but your camera/meter only tells you what to do as if it were middle gray so you have to put it in the appropriate zone to record it accurately.
Your camera/film has a finite dynamic range though. For very contrasty scenes you should bracket your photos (go at least one zone down and one zone up) so you have at least three to choose from, to combine through HDR (Photomatix Pro is the best), or to blend exposures with layer masks in Photoshop.
I could ramble on for days about the subject but I tire and want to do other things now. Maybe others can add to the discussion or expound on what I've put forth.
If I were you, I'd save a descriptive picture from Google Images of "The Zone System" to your phone to help you remember the zones.
Also, buy at least Ansel Adams' The Negative on Amazon. It was written during the days of film but it still has information you can use; it's best to hear from the master of exposure himself how to manipulate light to your will.