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“Dynamic Range” in photography refers to the ratio between the two most extreme values of light within an image. This is from the lightest to the darkest tones. So the “dynamic range” of a photograph is the difference between pure white and pure black. The term is also used to describe the “dynamic range” a particular camera has. Dynamic range is important to understand in photography to ensure you know the limitations of cameras and to make sure that your photos are correctly exposed. This quick beginners guide should help you understand the basics of dynamic range in photography.

Limitations in cameras

The dynamic range of a camera is measured in what are called “f/stops.” The brightness level of the camera doubles with a one-stop increase. Human beings can see about 20 stops, and a top of the range camera has about ten stops, 14 in some of the really high-end cameras. This means that the human eye sees a much more comprehensive range of tones.

For example, if you have ever taken a photograph on a sunny day and the photo has turned out nothing like what it looked like to you, you’ve experienced the limitations of the dynamic range of the camera compared to the human eye. But remember this is not your limitations as a photographer, it’s the limitation of the technology you are using.

The dynamic range of screens and printers is even less than that of a high-end camera. So, even if your camera can capture a high number of stops, you may have to edit the image to translate the dynamic range to that of a screen.

An example of a situation when the photograph doesn’t do the real scene justice in terms of tonal range. There are also areas that are underexposed on the rocks and overexposed in the sky.

Understanding the impact of dynamic range

As a photographer, running into dynamic range issues is something inevitable, but you get better at addressing the problems the more you come across them. If the dynamic range of the subject does not exceed that of the camera, your photograph will be correctly exposed. If the range is extensive, then it will affect one part of your photograph, and it will be under or overexposed.

When the dynamic range of the subject is broader, you need to choose where you want to lose detail, in the highlights or the shadows. Generally, it is better to expose the highlights so that they have more detail and sacrifice the details in the shadows as often you can recover these in post-production better than highlights.

Thankfully, there are techniques you can use to lift shadows like using a fill-in flash or lighting up the areas using a reflector. You can also invest in graduated neutral density filters (GND) to help balance out the dynamic range in some scenes. These filters are essential in say landscape photography where you often face a broad dynamic range. Below are some of the techniques you can use to ensure you get a better dynamic range in your photos.

The highlighted red area is overexposed and completely white. A GND would be useful in this type of scene.

Graduated neutral density filters

One of the major challenges when photographing landscapes during what is the best times of the day (early morning or late afternoon) is that the sun is low in the sky. Often this means you are faced with a bright sky and a dark foreground. This is one of those scenarios where the dynamic range of the scene might be too much for your camera. If you expose for the sky your foreground will be underexposed (too dark). If you expose for the foreground your sky will be overexposed (too bright).

In this scenario a GND filter is placed in front of the lens and can be rotated to reduce the brightness of the sky, allowing you to expose more of the shadows while darkening the sky. These filters come in a range of different strengths that can reduce the brightness of the sky by around three f/stops. These filters have a dramatic effect and are the quickest way of matching the dynamic range of the subject with that of your camera.

HDR Photography

One way of overcoming problems with dynamic range is High Dynamic Range (HDR) Photography, where you take the picture at multiple exposures and then combine the images into one final composite in post-processing (some cameras have an HDR setting that does this in-camera for you).

For this type of photography, a tripod is essential if your slowest image of the range is going to be at a slow shutter speed. A tripod will also ensure that you take the same image and there is no movement. If your camera doesn’t have HDR mode, you will need to set your camera on manual and then take the multiple shots adjusting your exposure from underexposing to overexposing.

Make sure you don’t adjust the aperture as the depth of field will be altered if you adjust the aperture. You need the images to be identical to merge them effectively.

Different time, weather, or from a different Angle

If the subject or scene you want to shoot is problematic because the sun is too bright, you can often overcome this by taking the picture at a different time of day, when for example it’s a bit cloudier or the position of the sun in relation to your scene has changed. This option will decrease the contrast and bring the dynamic range of the subject closer to that of the camera. Simply ensuring that you have your back to the sun when taking a photograph can make a difference in whether it is overexposed or not.

Use artificial lighting or a flash

You can use artificial lighting or a flash to add light to the darker parts of the image. This option decreases the difference between the lightest and darkest areas of the image and allows your camera to capture the entire gamut of light in one photograph.

When a flash is used, the light on the subject is closer to the amount of light in the background, and this narrowing of the dynamic range is often enough to capture the image effectively without any need for editing.

A flash is an excellent tool for capturing high contrast scenes, but it takes practice learning how to balance the light from the flash and the natural light. An off-camera flash is even better, but it can add to the amount of time it takes to take the shot as well as to the amount of camera gear you have to carry around.

Photo editing

There are some scenes when it is virtually impossible to deal with dynamic range problems in-camera, and you will need to use photo editing software to adjust the contrast. But the likes of Lightroom and Photoshop have come a long way in the last 10 years in being able to recover the areas which are underexposed or overexposed. So don’t be afraid to try to fix your images in post-production if needs be.

Cameras have limitations in the amount of light they can capture. When a scene’s lighting extends beyond the capabilities of the camera, these tools and techniques can still help you create a dynamic photograph of the scene. As you experiment with each of them, you will learn which is the best solution to use in a particular situation. You will soon be taking a dramatic high contrast image despite the constraints of the dynamic range of the subject or the camera you’re using.

Undoubtedly in the innovation of digital photography changed the world of photography forever. Gone were the days of analogue photography. Darkrooms turned into storage space, and photographers could now take a vast number of photos at no extra cost.

Digitization in photography also brought on a plethora of new technology, photo editing software and tools for photographers to be able to use. One of these was the histogram.

Background

The histogram is found in almost any modern image editing software and digital cameras. Yet it still intimidates many amateur photographers. The reason is that for starters, the mountain-like shape of the graph coated by a range of different colours can be a nightmare on its own to look at with no prior experience or knowledge of histograms. While they may seem complicated, they’re pretty easy to use. All you need is just a basic understanding of how they work.

Previous to digital photography, the film had to be developed before it could be known for sure whether the images had a good quality of exposure. These days, cameras are designed to focus on exposure on the scene as a whole. However, there are instances where the exposure may not suit most of the image; histograms were introduced into cameras to fix this very problem.

What is a histogram?

It’s a graphical representation of the tonal values of your image. Simply put, its purpose is to show you the distribution of tones in your photograph. Dark tones are displayed on the left of the histogram, signifying 0% brightness. As you move to the right, the tones get lighter until they turn white, indicating 100% brightness on the right. In the middle, we have mid-tones, which are neither dark nor light.

Why use the histogram?

An important reason to use a histogram is to evaluate your photo to check for ‘clipping.’ The term ‘clipping’ is used to describe whether there is a region that is either overexposed or underexposed, to the point where the sensor does not pick any detail. Overexposed photos are those that are too bright (white). In the case of an overexposed photograph, there will be a significant rise on the right of your histogram touching the side of this graph. This indicates that a portion of your photo is completely white and without detail and that there are blown out highlights, which can be a big problem.

An example of an overexposed image. Notice how the histogram is bunched to the right.

It can also happen with the left side of your histogram, which may mean that your photo is underexposed. Your image may be too dark, with too many shadows and black tones. That being said, black areas in your print may not be a problem if, for example, you’re shooting, a night shot. But where possible you should try to avoid large areas in photos which are completely black.

Clipping is challenging to catch with the naked eye, and the process is hugely simplified with a histogram. Understanding histograms will help you capture more balanced images. Sometimes an image may look fine on camera on a small LCD screen, but once uploaded to a computer, it can appear to be too dark or too bright.

An example of an underexposed image. Notice how the histogram is bunched to the left.

How do you read a histogram?

Some cameras show you the histogram before you take a shot (called a “Live View”) while others display it afterwards. Consult your camera manual to figure out how to display the histogram. Remember that the scale goes from left to right, dark to bright. The taller the peak, the more pixels of that brightness there are in the image. If there is a great deal of contrast in your photo, there will be fewer pixels appearing in the middle of your graph. How high your peaks are shows the number of pixels in that particular tone.

The reason many photographers prefer to use the histogram while out in the field is that they have a chance to take another shot. For instance, if the photographer finds the exposure is off, and there is an area that is blown out, it will have no detail at all. Even though editing software is pretty powerful these days, in extreme cases, you won’t be able to fix this in post-production. The colours on the graph are essential as well; if a tone is too bright, it may cause the picture to be too saturated and lose detail. There are generally five different colours on a histogram: black, white, red, blue, and green. The black and white graphs are meant to showcase the tones of your photograph, while the red, blue, and green are intended to display the brightness of those colour channels. You can find histograms in editing programs like Adobe Photoshop and Lightroom, and while they may look different, they function just the same way as the histogram on your camera.

The perfect histogram

Many people wonder what the ‘perfect histogram’ looks like. There is no such thing. There is, however, an ideal histogram, which has pixels spread throughout the axes with many mid-tones. The reason this type of histogram is considered superior is that it allows flexibility when it comes to processing the image. Since you have tons of information captured in the photograph, you’re able to generously decrease or increase shadows and highlights before you see any kind of decrease in quality. It also means that there are no clipped highlights or shadows.

The ambiguity of the histogram arises by the fact that it is open to interpretation—some artists like spikes of solid black or vibrant tones. It’s up to the photographer to decide what works. While you can undeniably benefit from a histogram to correct your exposure, it must also be taken with a pinch of salt. Just because your photo is inclined towards a specific tone, doesn’t mean that it is incorrectly exposed. Some artists stylistically choose to break the histogram rules purposely, which is completely fine. The histogram’s job is to show you what’s going on so that you can consciously see when your photograph is the exception to the rule.

An example of how you can tweak an image in post-production by using the histogram as a guide to get a better overall image.

Histograms are useful for photographers of every level. Not only are they not overly complicated, but they also contain necessary information about your shot that can help you get the most of your photography. Getting more familiar with histograms will change the game and help you shoot and edit your photos better. The days before histograms are history so make sure you put your new knowledge to work!

What Is Dynamic Range In Photography?