Underexpose your Digital Pics for Better Results
Digital cameras continue to get better, faster and easier to use. But understanding the difference in light sensitivity between film and digital cameras can help you get better results. This article is meant for photographers and artists, and it is presumed that the reader has a basic knowledge of photography concepts.
Metering Madness
Through-the-lens, or TTL metering has come a long way since my first Minolta’s “needle and hoop” meter. Today’s digital cameras have a host of metering options from spot metering, to average metering and preset scenes. As a photographer it is your job to get comfortable with your camera’s metering system in the conditions under which you shoot. RTFM is a term that carries over nicely from my old IT days…it stands for Read The Frickin’ Manual, and since each camera model meters in different ways, it’s something you’ll want to do every time you get a new camera. The word photography literally means “painting with light”, and since TTL metering has made simple what used to require a great deal of thought, putting in a little thought every now and then can often mean the difference between a decent snapshot, and a quality photographic image.
For most of my work, spot metering works for me…but use whatever method works for you. Most metering approaches will give you good results under most conditions, which is the reason they’re available on the camera. I like spot metering because I’ve been using it a long time, and have an ingrained pre-shot routine in which I point the spot at the part of my composition I wish to expose for (more on this below), recompose my shot and pull the trigger. Some cameras will have an “exposure lock” feature which is very helpful when you are shooting under conditions where the light does not change from shot to shot.
As for special situations, meters will still let you down (albeit less than they used to). Scenes in the snow, or at the beach will still tend to be overexposed by most meters (hence the “beach” scene metering mode included with many consumer cameras. Anyone who’s taken a photography class knows that adjust your exposure to compensate for the increased volume of light to prevent washed out (blown) highlights. This concept of “exposure compensation” is what this article is all about.
Digital vs. Film
The bulk of my experience shooting film was using Fujifilm Velvia 50, and although it produced astounding color and ultra fine grain, it was a slow (50 iso) film that had a limited range of light intensities it could represent in a single image. A great deal of thought (and exposure bracketing) went into making sure the image reflected what I was trying to communicate.
Specifically, color slide films require that we expose for the shadow areas, as they were prone to get muddy and lose detail when the film didn’t get enough light. This meant adding a stop or sometimes two, either in the exposure, which was more effective, or in processing (push processing). The key, however, was knowing what part of your composition you were using to determine the correct exposure. With color slide film, this is the shadow areas, as these are the areas where you lose detail when you screw up your exposure settings.
Digital sensors, on the other hand, while allowing the photographer greater latitude, tend to lose detail in the highlight areas. So while with positive film I was exposing for the shadows, when shooting digital I expose for the highlights. Because we’re talking digital now, my post processing is done in Photoshop, where I can use Camera Raw’s Exposure, [highlight] Recovery, Fill Light and Blacks sliders to get my detail back from the shadow areas. That’s what it boils down to with digital…you can get the shadows back, but once the highlights are blown, they can’t be recovered.
Lying to your Camera
To simplify shooting under most conditions, I utilize a feature of my camera called exposure compensation, to reduce the amount of light reaching the sensor by one to two stops. As with most things, moderation is the key in that the more you “push” the exposure in post processing, the less natural your image will look (just like film). Less is more. Also, underexposing by, say a stop, translates to a shutter speed one stop faster, when shooting in aperture priority mode as I normally do. This means it’s a little easier to freeze action and shoot handheld, but also means I have to use stronger filters to induce a longer exposure when I’m trying to show motion blur, in say shooting a waterfall. A small price to pay for better quality images.
How much I compensate depends largely on experience, lighting conditions, and examination (so called “chimping”) of images’ histograms on the camera’s LCD screen during the shoot, an advantage that film can’t touch. Experimentation is rewarded with immediate feedback, and therefore makes it easier to produce images with more impact, that more expressively communicate the vision of the artist behind the camera.
Conclusion
It is my firm belief that one of the challenges of being a photographer is keeping the technicalities of the tools we use from coming between us, and communicating effectively with the viewer. Just like a painter need to be able to recognize the difference between using a Kolinsky brush as opposed to a synthetic fiber brush, the artist photographer must understand the tools and processes of our medium. Any tools that simplify the process of shooting, as long as we understand their limitations, help the photographer to concentrate on more artistic aspects of the composition.
Happy Shooting!
Further Reading
An excellent source of information on exposure and the foundations of the modern photographic processes remains Ansel Adams’ instructional books The Camera, The Negative, and The Print. The Negative is probably the most important of the three today, as this is the book where he outlines the ground breaking Zone System, used to determine correct exposure. You can also find a wealth of information on exposure by googling “Zone System” and “BTZS“, a related, more modern iteration of the Zone System (BTZS stands for Beyond the Zone System).
