‘Dynamic range’ is a term used to describe the range of brightness, or levels of light, from the brightest white to the darkest black.
In photography, this term can be applied to a scene, but it’s also used when talking about camera sensors.
Dynamic Range of a Scene
When we talk about the dynamic range of a scene, we are referring to the difference between the brightest and darkest areas within the scene.
For example, a bright, sunny day often creates a setting with a very wide dynamic range as it includes both bright whiteness as well as dark shadows.
You can see this when you view the histogram for the scene. The tonal values for the scene with a large dynamic range will cover the entire range of the histogram and may even bunch up along either or both ends of the graph–a situation known as ‘clipping’–indicating that detail in the scene may be lost in the brighter or darker areas.
On the other hand, a cloudy, overcast day can give rise to a scene with a very narrow dynamic range.
The histogram shows that the tonal values for this type of scene are found mostly in the middle of the graph, with very few, if any, pixels found toward the edges.
Dynamic Range of a Camera Sensor
A camera’s digital image sensor has a fixed dynamic range that determines the range of brightness levels that it can record when shooting an image.
This means that your ability to capture all the tones in a scene depend on whether the brightness levels in that scene fall within your camera’s dynamic range.
You can get a sense of this by looking at the histogram on the back of your camera. If the histogram is clipped–if the values are bunched up along either or both of the ends of the graph–then the brightness levels in the scene may be beyond your sensor’s dynamic range.
Working with your camera’s dynamic range
If you find that the scene you are shooting has a dynamic range that’s too large for your camera’s image sensor, there are a couple of steps that you can take that can help.
Shoot at a different time of day
If the dynamic range problem is being caused by the brightness of the sun, try again later in the day when the sun is lower in the sky.
Move your subject into the shade
If you are shooting under a harsh midday sky, you can reduce the dynamic range by moving your subject out of direct sunlight and to the shade or indoors.
Add light to the shadows
You can reduce the dynamic range in a scene by lightening up the darker areas. Consider using a flash or a reflector to add light to the shadows.
Darken an overly bright sky
A graduated filter can be used to reduce the brightness of a too-bright sky and reduce the brightness levels in the scene so that they are within your camera’s dynamic range.
Raw images capture more information than JPEGs do and that gives you more leeway to recover lost shadow and highlight details in post processing.
HDR–High Dynamic Range–photography is a technique for capturing scenes with a dynamic range that’s beyond your camera’s image sensor.
In HDR photography, multiple images using different exposure settings are taken of the same scene. The images are then combined in post processing using Lightroom or Photoshop to create a photo that shows detail in both the shadows and the highlights.
The video below shows this process in action using Lightroom.