Dynamic Range

The reason dynamic Range can be a problem is that a camera can see less dynamic range than the eye. So when the dynamic range exceeds the camera’s range, which happens on a bright day, the resulting image will never look like what you are seeing. Often it means either your highlights or shadows do not come across in the image.

For more detail see the article What is Dynamic Range and Why Does it Matter for Photographers?

This is one reason photographers prefer to be photographing during the early morning or evening light. Provided you are not pointing your camera within 90 degrees of a risen or setting sun the dynamic range is usually within the capacity of the camera. The other added bonus is at these times of day colours are richer and tones are more subtle.

When photographing in a high dynamic range situation the range between the shadows and highlights of a scene will be extreme. So in these situations, the photographer risks losing the highlights or shadows in the image. So understanding this challenge and having some strategies in this situation would be useful, hopefully, the following strategies may be of some help.

Exposure Compensation Dial

One of the first strategies evolves out of the camera’s ability to capture shadows better than highlights. In the digital world, unlike film, when your highlights are overexposed or “blow out” they are not recoverable. In the case of the sky, attempts to bring back detail result in strange unworldly representations of the sky and clouds. That is not to say some details can not be recovered but this often depends on the sensor and age of the camera. In my experience as your sensor gets larger more detail can be recovered. The shadows even when they are black contain far more detail. Recovering detail from the shadows depending on the camera may result in the introduction of some noise into these areas of the image.

Understanding this difference, many photographers intentionally adjust their compensation dial a quarter stop darker and deliberately slightly underexpose every image. It is kind of a insurance policy that they apply to all their photographs, however not all photographers find this method the best approach. One issue with this method is with the shadows in an image. Underexposing shadows will introduce additional noise, which will be more apparent if you have to open up the shadows. Another problem with this strategy is you are darkening the tonal values in the image creating a slightly high contrast in the RAW file. This means when you are trying to bring back the tonal values there is less information for your processor to work with. Finally, the colours in the image can lose some saturation and chroma impacting your ability to recover the colour range of the scene.

This strategy is not necessarily a bad one and many photographers do use it, but understanding how it works is helpful in deciding whether to use it. Depending on your aesthetic direction or the atmospheric conditions you may want to use another strategy.

Manually Selecting the Exposure

In this method, your camera should be set to manual ISO, Aperture and Speed. Let’s assume it is a landscape with some bright sky and some forested areas that are quite dark. Point the camera into the sky and then set the exposure so the metering needle comes to rest at zero, then point the camera down and into the dark area of the forest. Then make note of how many full stops difference there are between the two areas. This will give you a lot of information about what might happen with different exposures. If the difference is three or more stops you may want to consider, using your exposure bracketing mode. If it is less, depending on your camera, of course, you may consider exposing for the sky or exposing for somewhere in between. These are personal preference decisions and are dependent on your post-processing skill level and camera type and age. If you do this often enough you will know right away in which direction you want to go.

If you are in a forest and the light is stippled through the trees then you may need to adjust your exposure until you see the blue of the sky coming through the trees to estimate the correct exposure for the sky.

HDR Merge Strategy

The use of HDR or High Dynamic Range usually refers to the use of bracketing three or more of the same image at different exposures, then merging them into a single file. However, you can, depending on your camera, process an image to bring back a certain amount of the dynamic range. Often can result in an image that looks like an HDR image. If you overdo the process, critics may exclaim “It’s HDRed” and the term in this context becomes a pejorative. When creating an HDR photograph care should be taken not to overdo it unless that is your intention. The two images below from the 500px blog illustrate an image verging on being overdone and one where the HDR process is more subtle.

HDR verging on being overdone, from 500px.
A more subtle use of HDR to deal with dynamic range, from 500px.

The process is relatively simple and can be done handheld with most modern cameras which have a high frame-per-second (fps) bracketing rate, provided you are relatively steady when taking the image. Using a tripod of course may render a better result, but the difference is not always apparent. Six or so years ago I found taking at least five brackets using partial stop differences was necessary. However, with the new cameras on the market with broader dynamic range capacity I am finding three brackets work well. This of course depends on how extreme the dynamic range in the image is at the time. In general, I will set the camera to bracketing mode, set the fps at its highest setting and set the exposures one to the correct exposure, one a full stop darker and one a full stop lighter. These are then imported into RAW processing software (Lightroom, Photoshop, Capture One, et al) and then automatically merged. If something was moving in the image you may need to adjust the ghosting feature.

If you do find yourself doing a lot of HDR become critical of the results there are a lot of other stand-alone HDR processors on the market. I no longer use these stand-alone programs but I have experimented with them in the past and I found Photomatix to be quite good.

In-Camera HDR

Fujifilm allows for automatic in-camera HDR which can produce a RAW and JPG HDR file, without having to bracket. The video below explains this process. Other cameras in the process should work in a similar way.

Post Notes

Just a post note about dynamic range, Rob Will has suggested the following.

Historically dynamic range was never really an issue. Photographers and cinematographers embraced contrast and many of the most notable works of photography and cinema are extremely high contrast. Would Citizen Kane or The Third Man have such an impact without their limited (by today’s standards) dynamic range? What about German Expressionism? 

These days, there is a school of thought that says everything in a photo needs to be equally visible. Our eyes don’t see like that in the real world. They can quickly adapt to dark and light, but we don’t see everything equally exposed all at once. That is why the HDR look is so unnatural. Even the second photo in your article shows significant light halos around the truck. You would never see that effect in the real world.

What Rob is pointing out is our eyes have a very narrow focus but as we scan a scene and they rapidly adapt to the dynamic range. Our brain thinks it is seeing everything, but as the eye moves from one focal point to the next our memory fills in the areas where we have been focusing, and our peripheral vision looks for any sudden changes in what we think we see. So most of what we think we see could be characterized as virtual reality. This accounts for the phenomena of finding some glaringly obvious item in a photograph we did not remember being there. All of this makes me wonder at why there is a trend toward greater dynamic range. Is it about making the image look like what we imagine we see? Is it about making the image different from the massive amount of images we are bombarded with every day? Is it about exploring and experimenting with the breadth of possibilities now available in the digital world, and at the moment this is just popular?

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