Exposure Bracketing: What It Is and How to Do It

How many times have you snapped a beautiful scene, only to be disappointed when your images don’t adequately represent the reality? Though the camera’s images sometimes fall short, have no fear, because bracketing is here.

The Human Eye Versus Camera Sensor

Despite the obvious differences in vision and photography, our eyes and cameras work in a similar fashion, at least on a basic level. They both utilize a front lens for focusing and rely on a variable opening (aperture or pupil) to let in the right amount of light.

Imaging technology has come a long way, but the human brain still has far more processing power and can detect a larger range of light in a scene than any modern camera can in a single exposure. This is true, however, only in the comparison of human vision to individual snapshots. Over the time of a long exposure or combining frames,  a camera has a crucial advantage over the human eyesight .

Regardless of the light-gathering capability of a given long exposure, you’ll still sometimes find that your images are dull and lackluster compared to your eyes’ perception of the scene. When photographing on a sunny day, for instance, shadows and bright blowouts are commonplace and frustrating.

"But I shoot raw," you might say, pointing to your spiffy new t-shirt that boldly proclaims your camera settings to the unwashed masses of the photo-newbies. Maybe you feel you’re making maximum use of your camera's sensor, so brag a little (there’s nowhere else to go).

It's true, raw files are essential to capturing dynamic range in a scene. But I promise this: at some point, you will be in a situation in which bracketing is necessary, and a single raw file isn't going to cut it. We'll delve into those exact situations later, but first, let's talk about what bracketing is.

Defining Bracketing

By definition, bracketing is photographing a series of the same image, tweaking a single setting as you shoot. This results in a range of images that can serve various practical purposes.

Typically, the term "bracketing" refers to changing exposure during multiple image captures. In other words, bracketing is gathering frames at various light steps. This can be done to choose the best exposure or later combine the photos for one image with more dynamic range. The end result of the latter creates work more attractive and true to human vision.

You can bracket for any setting. If you take a series of images at different focus points, that's focus bracketing. You can bracket ISO settings or even white balance in order to find the best result. Exposure bracketing is typically done with shutter speed. Keep in mind that if shutter speed is changing and your subject is moving, any motion within the frame can cause problems in compositing later.

If you're in a low light situation without a tripod, you will want to ensure that the slowest shutter speed in your bracketing range doesn't dip below handheld territory. This helps you avoid blurry images you didn't notice while you were snapping away.

Why Should You Exposure Bracket?

If you only shoot single exposures and don’t have to worry about full tonal range, bracketing might not apply to you. For practically everyone else who has not used this technique, bracketing expertise is handy in many situations.

My entry level photography began as most everyone else’s does: taking snapshots. Since journalism relies on the snapshot, this basic shooting technique has arguably produced the bulk of the world's most important photography, at least historically.

Of course, I started out taking single exposures. Then, moving into different genres, I became familiar with bracketing through the popular processing method known as HDR. We'll discuss HDR later.

Manual Bracketing Versus Auto Bracketing

Automatic Exposure Bracketing

Most modern cameras come with an option to auto bracket.  Once auto bracketing is selected, decide how many frames you'd like to capture and set the range between each of those stops accordingly. For instance, if you'd like a series of five images all taken with just a single stop of light between them, your camera display should look like this:

Auto bracketing is great for handheld shooting. After choosing your auto bracket settings, set your shooting mode to burst and capture everything you need with one prolonged depression of the shutter. This way, your images will be easier to align, since little movement is created during burst shooting. You can also use a tripod.

Manual Exposure Bracketing

Manual exposure bracketing involves pushing your camera dial between each exposure. This is best achieved on tripod, though you can also do it handheld. The downside to handholding while manually bracketing is that your frame might jump around each time you move the camera dial and depress the shutter. This can produce problems when aligning images later on.

One advantage to manual bracketing is that you can push the camera as far one way or another as desired to gather dark or bright data, instead of relying on a set range of exposures to capture what you need (as in auto bracketing).

After you've taken your series of bracketed photos, you will merge them in post-processing. You have two options available: HDR and compositing. Let's take a look at both options, and I'll note why I prefer compositing over HDR for most situations.

HDR 

This processing technique stands for "high dynamic range," because it creates images with a more complex tonal range than a single exposure. HDR can be done in various ways: in Lightroom (available in more recent versions) or Photoshop, as well as via third-party software. You'll find that most of the software comes at a reasonable cost.

HDR Pros

• Fast processing, good for artistic or bulk work. More common option for hobbyists because it's simpler, but many pros love it as well.
• Utilizes tone mapping, which allows you to control the range of highlights and shadows.

HDR Cons

• There's a learning curve involved. When done incorrectly, images can look garish and harsh (which might only be a positive if you're doing surreal fine art).
• Default presets are usually subpar, and usually better when you set them yourself.

• Less respected by professionals than compositing, as the output is often lower quality.

Compositing Exposures

Compositing Pros

• Best result for quality. Technique more commonly used by pros.
• More realistic output of images.
• More control over ghosting (aberration created by movement) and range of tones.
• Less noise in final output than HDR.

Compositing Cons

• Learning curve: requires at least a basic understanding of layers and layer masks.
• Time-consuming.

I prefer compositing, but many talented photographers do rely on HDR. Landscape photographers in particular often benefit from HDR, and others find it useful in the right context.

Still, HDR is often overused or inappropriately applied, producing a harsh, "overcooked" image that looks like a movie scene one would need a hazmat suit to enter safely.

What sort of applications do you use bracketing in? Next week, I'll delve into the various genres that use (and don't use) this technique, so please chime in with your ideas below.

Lead image by Jeshoots via Pexels.