In order to understand how photography exposure works and the effect it has on your photographs, you need to get your head around a few more things. The first one is learning to look at the world and see it the way your camera sees it.
Prefer to see it in action? I explain exposure and dynamic range with live examples in this video. Everything below is the written version.
TO UNDERSTAND EXPOSURE, WE FIRST NEED TO UNDERSTAND DYNAMIC RANGE
Cameras and people see light differently. The design of a camera is very similar to the human eye, but they don't see the same. For instance, we aren't as good as cameras at noticing the color of light, but our eyes have a better dynamic range than any camera.
The human eye, at this moment in time, is about twice as advanced as the modern camera. People are able to see things in the deep shadows and in the highlights at the same time; cameras can't.
The human eye doesn't see the scene the way it is photographed below; therefore, we need to learn to look at a scene and visualize how it will look on camera. With time, it becomes easy to accomplish.
The human eye can perceive approximately 20-24 stops of light, whereas modern cameras are limited to 12-15 stops. Therefore, using a camera is always a matter of compromise: we have to decide toward which light values we are going to expose our image.
A "stop" is simply a division of light tonality, with each stop representing a doubling of the level of brightness. For convenience, this range has been divided from 0 to 24.
With a camera, we are limited in our light-capturing options: we can focus on the brighter, middle, or darker range of the image.
We can extend that range in editing, or by using methods like HDR, but the latter is challenging when photographing handheld and is mostly used in photography where the camera is stabilized on a tripod.
SPLITTING THE SCENE INTO LIGHT VALUES
To gain better control of the light in our scene, it's advisable to observe it and categorize it into different light values. To simplify, let's use three categories. We don't really need 24 stops to understand how exposure works; Brights, Mid-tones and Darks will do.
- Brights: the brightest parts of the image, such as the sky or bare bulbs.
- Mid-tones: the name is self-explanatory; neither the darkest nor the brightest parts of the scene.
- Darks: the darker parts of the image.
WIDE DYNAMIC RANGE
A wide dynamic range occurs when you have all three lighting categories, very bright, mid-tones and very dark parts, in a single image. In such cases, we need to prioritize our exposure: are we going to expose for the brighter parts of the image or the darker ones?
Prioritization makes it harder to work with a wide dynamic range. Images with a wide dynamic range tend to have more contrast.
NARROW DYNAMIC RANGE
A narrow dynamic range occurs when you have only two light categories: mid-tones and shadows, or highlights and mid-tones. You don't have the same broad spread of tonality across the image as in a wide range; all the light values sit more or less in the same area.
While working with a narrow dynamic range, most of the details can be seen in both the dark and bright parts of the image. A narrow dynamic range contributes to lower contrast.
IMPLEMENTING DYNAMIC RANGE IN OUR PHOTOGRAPHY
In most cases (not always), we aim to narrow the dynamic range of the scene. That leaves us with only two light values to deal with, and that makes exposure choices easier.
This can be achieved by recomposing the image so that the brightest or darkest parts are simply out of the frame. You can also do this by cropping at home, but I strongly recommend trying to do it in-camera and on location. This way, you learn to notice these things while shooting.
Let's compare the two images.
DYNAMIC RANGE PROBLEM-SOLVING TIPS
- Narrow down the dynamic range of the scene.
- If you have all three levels of light, try to narrow them to two.
- You can do that by excluding the brightest or the darkest part from your frame.
- Then use your exposure to control how your frame will look.
WHAT IS "THE RIGHT" EXPOSURE?
While the Wikipedia article on exposure tends to complicate things, and a beginner can get confused, I will do my best to explain photography exposure in the simplest way possible.
- Exposure, in simple terms, refers to how bright or dark your image appears. If your image is too dark, in photography language it's called underexposed; if it's too bright, it's called overexposed.
- Correctly exposed images are neither too dark nor too bright; they fall somewhere in between.
- But "the right" exposure is the one you choose to use, not necessarily the "correct" one. Sometimes we prefer things brighter, other times darker.
So the next time you come across a comment about a photograph being overexposed or underexposed, try to look past the technical aspect.
Instead, consider whether the photograph is exposed correctly according to its intended idea.
Does it convey the message effectively?
Would adjusting the exposure change the photograph's impact?
The photographs above may be technically underexposed or overexposed, but that is the creative idea behind them.
If they were technically correct, the visual message would be completely different.
SUBJECT TO BACKGROUND RELATIONSHIPS
When exposing your photographs, keep in mind that your subject and your background might have different exposure values.
This is the most common exposure mistake photographers make!
Photographer gets excited about the subject and doesn't notice that the background has become too bright or overexposed.
Remember that your background and your subject are parts of the same frame; when planning the exposure for one, check how it affects the other.
The general recommendation is to expose for the subject, but sometimes we break that rule.
COMMON PHOTOGRAPHY EXPOSURE MISTAKES AND HOW TO AVOID THEM
PHOTOGRAPHY EXPOSURE TIPS
- Camera light metering systems can get confused when direct light hits the lens, resulting in incorrect readings. To fix this, you may need to brighten your exposure.
- Metering can also get confused when a large dark object dominates the frame, again giving inaccurate readings. In such cases, adjust your exposure to darken it.
- Typically, aim to have your subject appear brighter than, or at least equally illuminated as, the background. This progression from bright to dark creates higher contrast and helps your subject stand out.
- When subject and background share the same tonality, you often end up with lower-contrast, flatter photos. If that's not your intent, consider changing your position so the light on one of them differs.
- When capturing a dark subject against a brighter background, your options are limited: use a flash to even out the light values, or expose for the subject and accept a brighter background.
- Remember that light and exposure are only one part of composition. For more photography tips, check my education page.
I hope you found this exposure guide useful. Welcome to add your own exposure tips in the comments!