Taking the Shot EXPOSURE & LIGHT

after taking it. This, of course, is a highly valuable tool and always the first way to evaluate the scene and determine the settings to shoot with. But, it can be misleading. Things can get in the way to fool you when doing this. The brightness level of your LCD screen, for example, is one. Then there is the brightness where you’re actually viewing the image (full sun vs. a dark hallway). Between these two things, it’s evident that simply viewing the photo is rather inexact. Fortunately, memory is cheap, and you can get away with taking a few of the same photo at different exposure levels. However, if you want to get scientific and very precise, all digital cameras come with what’s known as a “histogram” function, where you can read the light levels of the photo in a very precise and scientific way.

Histograms, however, are not the be all end all of light measurement. Your eyes should always be your first and last lines of defense. They are, though, a great way to see if there are any major problems going on with a shot.

In looking at the above histogram, the spikes, although relevant in terms of which dark/light profiles are most commonly represented in the photo’s exposure, are irrelevant information for making any changes to the next photo’s exposure. For instance, one might be photographing fall aspen trees, with shades of light gray represented more frequently due to their light-colored bark.

What we’re really looking for in a histogram is any major swing to one end of the graph or the other. That is, a major curve at the extreme dark or light end, which would indicate that the photo is “scientifically” too dark or too light.

The above three histograms illustrate what we’re looking for (the top graph), and two scenarios that would cause us to want to reevaluate the photo and take another shot. When there are too many over or under exposed parts of the photo, data is lost, and not even the fanciest editing program can fix it.

Camera Metering

Unless you are photographing on full manual mode (usually designed with an “M”), your camera is choosing the appropriate exposure for you based on the scene. You can manually dial in an exposure compensation in order to correct what the camera “decides” for you. Each camera brand and model will look slightly different, but they will generally resemble the image on the next page, ranging from -2 to +2. Because of the brilliance of digital cameras, most will now allow you to preview the image based on whether you overexpose the shot by +1 or +2 or underexpose it by -1 or -2.

If not, you can always take a trial shot to see the result.

How A Camera Chooses Exposure

Cameras are smart, and they’re getting smarter with each passing year and with each new model that comes out. From point and shoot, to fullframe DSLR, and most recently mirrorless cameras, they decide what an “evenly exposed” shot ought to be. In the camera world, this even exposure means that the camera perceives 18% gray across the image. This has been determined through years of experimentation from camera engineers to be closest to what the eye sees naturally.

The challenge for the photographer is telling the camera whether it should look at part of the image to meter, use only a small point, or use the whole frame. The reason for not just using the entire image has particular importance with wildlife photography where the subject is the focus and thus prioritized for even exposure, even if at the expense of the background.

A prime example of this in the world of wildlife photography is when the animal stands out significantly from the background. In the case of photographing polar bears, it matters most how the bears are exposed, not so much the background. Although the red and brown willows are neat, they aren’t what you care about most – you want those bears as the centerpiece. In this case, one would want to manually use a metering setting that is in the center of the shot so that the camera doesn’t adjust to the darkness of the background, which would overexpose the white bears. If changing the metering mode is difficult to do (which it can be depending on your camera), the easiest way is to try and take a few different shots at varying exposure levels. Remember, it’s always best to get the shot right in the moment, so if you have to delete photos after you return from the trip, it’s better to do this than to have to make a major correction in Lightroom or another editing program.

For most cameras, there are four types of metering modes that your camera uses to decide which part of the photo it evaluates for proper exposure. As you can see from the red areas, evaluative is the most comprehensive, looking at the entire frame for proper exposure. This is ideal for landscape, scenic and general shots. Center-weighted gives more priority to the middle of the photo and is still appropriate for landscape and general shots. Both partial and spot metering are appropriate for wildlife shots, where the other elements of the landscape are secondary to a singular subject in the photograph. Needless to say, spot is the most pinpoint accurate of the two. But it’s important to remember when using partial or spot metering that where you auto-focus your camera becomes the point your camera exposes for.

Setting exposure metering modes like those on the previous page will best be done by looking at your camera’s manual, but plan on something in your camera’s menu resembling the below.

Most cameras have four metering modes. From the left, these menu icons represent center-weighted, partial, spot, and evaluative.

Rules Of Thumb

For a topic as important, and oftentimes confusing, as exposure and light in photography, it’s best to summarize things with some basic rules of thumb:

1. Always consult your eyes first and histogram second for shots that could be over or underexposed.

2. Don’t hesitate to take another shot, compensating for exposure in your camera’s menu with a +1 or -1 setting.

3. Choose the best metering mode for the type of photography that you do, and it will save you time in the long run.

4. Practice makes perfect. Getting comfortable changing your camera’s exposure settings (both modes and compensation) can be challenging. With practice, it will become second nature and you’ll get the shot each and every time – with very little editing to do afterwards!