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The zone system
A formula from one of the greatest photographers stands the test of time. Text and photos by Pinaki Chakravarty

It's easy to produce attractive photographs these days, and they will generally look better than what you saw through the viewfinder. As you compose your shot, a little computer is frantically keeping up, evaluating luminosity from each part of the scene. Your camera is probably tinkering with contrast and boosting colours as you shoot. But while all this back-office technology is making you look good, you have to accept that you have lesser control over what your final image will look like. And if you're after perfection, this will be unacceptable.

The heart of the image
At the heart of the problem is the first step, exposure. How you expose for a given scene will produce a domino effect that will tumble down all the way to your final print. You can fiddle around with each step along the way, but if your exposure is the way you want it you'll need to fiddle less. And produce an image that you want.

And that brings you to the crux of the problem, which is that your eyes register a greater range of tones than any camera is capable of recording, or any paper is able to reproduce. That means you have to pretend you see only the limited range that your camera can record, while looking at something that your eyes see in an entirely different light. This is a step away from reality, imagination based on technicalities. Simplified, one can call this process visualisation. Ansel Adams (1902-1984) was a master visualiser, and he trudged across the American wilderness with huge view cameras that used glass plates instead of negatives, carrying them on his back, hauling them up mountains by rope and across by mule. He distilled his technique into what he called the Zone System, a format as relevant with today's digital cameras as it was in the early twentieth century. Sheer technical simplicity and perfection.

The system
To match the tonal range of his media – glass plates, negatives and printing paper – Ansel assigned each level of luminosity in a scene to a 'zone.' He called the middle grey tone (he shot in black and white) Zone V. He progressed through the tonal range on either side of Zone V, from darker to lighter. Five steps below Zone V was pure black, at Zone 0. Five steps above Zone V was pure white, at Zone X. Both 0 and X would show no detail in a final print. Each step in between is a zone. Any tones that fall above or below won't register.

So now every time you compose your shot, you have to keep in mind that only a fraction of the tone you see will come into play. You have no say in this matter, and the faster you accept – and understand this – the better. What you can do next is decide which set of zones you want to choose in a scene. Remember that each zone exists only in relation to the other, and the entire set is linked together. So while you need to identify ten different tones (actually 11 when you count Zone 0), you have to set only one, like Zone V, the middle grey. Once you set it (or any other individual zone), each other zone will fall into place in relation to it.

Make it, then break it
Generally, images that have tones that range from pure black to featureless white, and contain the entire range of tones in between, look the most pleasing. Of course, this is a ridiculous statement to make, since there are as many reasons to break rules like this as there are to follow it. Your decisions make you the master.

The human eye sees thousands of tones. Now you have to pick 11 that you want from a composition. This isn't a wild scramble to see who picks the 'correct' one. There is no correct exposure – even if there was it wouldn't make sense because you couldn't capture all the tones of 'reality' anyway. Rather, you will look at a scene and think to yourself, "I'd like the rocks to appear very dark, but with the faintest bit of detail. To do this I'll assign the rocks to Zone I. This will put the crest of the waves on Zone X, which means that they will be brilliant white, while the water will fall along VIII and IX, with enough detail showing. The moss on the rocks and the plants will range across Zones IV-VI."

Imagine – you're now 'seeing' the photo not just through the viewfinder, but exactly how it will be reproduced. How fantastic it could be to know exactly what you will get in the end, one step closer to perfection.

Translating this into digital
Part of the reason the Zone System proved so important is that shooting film always involved a lot of guesswork, and you wouldn't know if you've botched the job until it was too late. You have less to worry about with digital, because you will see the result of your shot a millisecond later on the screen. Digital SLRs will even show you a chart called a histogram, mapping the tonal range captured. But this is only confirmation of a decision taken by either you or the camera, not the solution itself. Ultimately, whether you shoot with slide film, negatives, digital sensors or antique glass plates, the decision is the same: how do you set your exposure. As a handy little side effect, this will also prove to you that the basics of photography remain the same, no matter how much technology revolves around it.

The parameter that does change is the tonal range that is capable of being captured and reproduced, and this changes with the technology in time. Negative film has more latitude than slide film, and digital sensors are constantly expanding the range they can cover. Fujifilm's FinePix S3 digital SLR, for example, has a sensor specifically developed to overcome the issue of limited dynamic range. The CCD is able to expose at both low and high sensitivities within one shot by assigning a honeycomb of pixels to different levels of light. This allows for an image to have information from a darker middle grey and a lighter middle grey, plus the dynamic range surrounding them. Other noted exceptions are the Hasselblad medium format sensors, which are able to decode 16 bits of colour and expanded light information. It is also possible to overcome the problem of limited dynamic range by creating multiple exposures of the same scene. This is done by shooting the same scene twice, once exposing for the shadows and once for the highlights. The image is then overlapped and masked appropriately so that the resulting composite represents a wider range of colours and tones.

The deeper you delve into photography, the more you realise that it involves making images, not taking them.