Wednesday, December 19, 2012

Digital Exposure In Depth

The Illusion of Digital

There is an image that endures in my memory, a photograph of my grandfather with no less than three Nikon 35mm cameras hanging from his sturdy shoulders. This was not atypical. I grew up with cameras documenting every family moment, so it probably isn’t too surprising that I am rarely without a camera, especially when visiting family. On one trip to visit my brother, I was photographing his son, who must have been about five years old at the time. He stepped around to look over my shoulder. Frowning, he chomped down on the lollipop he had in his mouth and devoted both hands to turning my Mamiya RZ67 around and around – a huge medium format film camera in his tiny hands.

“Where’s the picture?” he demanded to know.

This was not an easy thing to explain to him. By the time he was old enough to ask the question, film cameras were already becoming exotic. Today, I doubt he could remember ever seeing one.

Digital cameras exploded the proliferation of what was already one of the most popular hobbies in the world. Less intimidating than chemicals and emulsions, the screen on the back of a digital camera provides reassurance that there is indeed a picture in there, and the promise that you already know what it looks like. If you don’t like it, you can just try again, at zero cost.

For those whose photography ends with sharing their images on web sites or through email, that reassurance is enough. For photographers who want to produce extraordinary images with precise control over their palette, and especially for whom the print is the final product of a photograph, it is necessary to understand that what’s shown on a camera screen is illusory, to learn how to work with that screen, and to understand its limitations.

Clipping

One of the fundamental differences between analog and digital systems is that numbers define the digital world. Specifically, the number of discrete tones or colors that can be captured is finite. When the computer detects that your digital camera has run out of numbers, no more information is captured. In visual terms, this means that your image suddenly goes from capturing some detail, to rendering pure black or pure white.

© Brian Dilg Photography LLC
This phenomenon is called clipping, and it is utterly unlike the gradual loss of detail on a piece of film (still leaving the physical grain of the film itself). It isn’t pure white or pure black that looks bad, but the transition from some detail to none that is tricky.

Clipping is a commitment, because you’re never going to see any detail in clipped areas later, no matter how skilled you are in the digital darkroom. There is simply no detail. You can make it gray instead of black or white, but that is not always a pleasing option.

Nevertheless, in some cases, you may choose to clip deliberately, as in this high-key portrait example. I wanted to underscore the feeling the woman was enjoying the warmth of the autumn sun, and I did so by overexposing. However, I was careful about what I clipped, which was the wall, not her skin. I like the brightness of the image as a way to convey the feeling of a blindingly bright sun.

By choosing to expose the image this way, I limited my options.  I had to produce a high-key rendering of the digital negative. If I’d tried to darken the RAW image later to a more normal-looking exposure, the wall would still be white, or even gray, which was not the desired effect.

In most cases, however, it is wise to protect your options by carefully exposing so that neither shadows nor highlights are clipped. If you do this, and are of course shooting in RAW format (never JPEG), you can produce an astounding range of interpretations from your digital “negative.”
© Brian Dilg Photography LLC
In the example image of the Manhattan Bridge in New York City (shot during a blizzard in December, 2010), I’ve shown two radically different interpretations from the same RAW file, as well as the untouched RAW as originally exposed. The low-key and high-key interpretations were produced straight from the RAW processor in Adobe Lightroom without using Photoshop. Since I exposed conservatively, I had plenty of detail in shadows and highlights that I could lighten or darken to suit the desired effect, either by preserving the detail or throwing it away to pure black or white. I think they both convey the feeling of the blizzard, but in radically different ways.

The interpretations were not intended to be compared or seen side by side. In fact, it is impossible for you to perceive the low-key image without isolating it on a dark screen. If do you, you’ll see that there are no black tones, and that there is subtle, but sharp, detail underneath the dark bridge.

The Nitty Gritty

Ultimately, I find that commitment is a very good thing, and that the forgiving nature of digital RAW mode has the same effect as too many options in all creative endeavors: uncertainty. I’ve noticed over years of teaching that constraints help creativity thrive.

While it is essential to experiment when you are a student or exploring new techniques, ultimately you need to find your own iconic style.  You’re never going to get there by avoiding risks and hugging the safe middle. Exposure is as much a creative decision as composition.  It is one that is mostly underused in the world of photography, still pretending as it has since its invention that it is a medium in which reality is objectively rendered.


Contributor Bio
:
Brian Dilg is an internationally published and collected photographer and award-winning filmmaker with over 20 years of professional teaching experience around the world. He is currently the Chair of the photography program at New York Film Academy, a film, acting, and photography school.