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In photography, HDR stands for High Dynamic Range. An often misunderstood term, there are actually two aspects of dynamic range to understand; the dynamic range of the subject and that of the camera.
As for the subject, the dynamic range is the amplitude of the tone from the brightest part (highlights) to the darkest part (shadows). In a daytime scenario, bright sunlight and reflections like on water or sheen on skin are your highlights, while dark shaded areas are shadows.
As for the camera, its dynamic range describes how much of that amplitude of tone it can capture in a single image. There is a limit. The human eye is capable of perceiving a much higher dynamic range than any camera or phone.
While a cloudy day shouldn’t pose a challenge to your camera, there are scenarios where it can’t capture the full dynamic range. For example, bright sunlight can appear washed out. There is a solution to this kind of problem though … yes, HDR. HDR was introduced as a way to increase the amount of dynamic range that can be captured in a single image.
How to master HDR with your camera or phone
Different camera systems offer various approaches to HDR. Most DSLR and mirrorless cameras offer exposure bracketing, in which a number of identical images can be captured consecutively, each with a different brightness value. Then merge these images using editing software into a final image with high dynamic range.
To understand what exposure bracketing can do, here’s an example: A camera with a dynamic range of 12 EV (exposure value) can offer exposure bracketing of ± 3 EV, thereby increasing the dynamic range up to 50%. It’s huge.
(Image credit: Canon)
Buy a new camera and it will likely have an HDR mode. It works the same way as exposure bracketing, but automatically captures images with different brightness values and combines them together for you in the camera, without the need for editing software. It’s a quicker process.
Up the ante, a number of smartphones apply HDR automatically, with “Smart HDR” in current iPhones being one example.
HDR is not to be confused with highlight and shadow compensation, where more detail apparently appears in those areas of the image. Technically speaking, this is not about creating an image with a higher dynamic range, but about lightening or darkening the detail already present in a single image, which could otherwise be recovered manually by editing.
When should you use HDR?
For the most part, we like to use HDR with caution. It certainly has its place, which is to subtly add missing details and thus improve image quality. A small lifting of the shadows, recovering the details in the reflections on the skin and the intense sunlight.
On the flip side, HDR can be overcooked and all sense of reality is lost, nothing more than when the shadows are overly bright and the final image looks flat. In other words, bring all tones to a midpoint.
This is probably an example of overcooked HDR, although it’s also a matter of personal taste and opinion. (Image credit: Shutterstock / Marshall Artist)
There are also scenario-based limits for HDR, one example being action. Fast-moving subjects can have a “ghosting” effect when combined with an HDR mode, because the subject is in a slightly different position in each image in the HDR sequence.
HDR could also negatively counteract the desired creative effects. For example, you may want a backlit silhouette without HDR revealing details in the shadows of the subject.
How does HDR work on smartphones?
In smartphones, there are too many examples to cover, but many include an automated HDR feature. The “Smart HDR” of an iPhone applies HDR by default, created using computational analysis of the captured scene. Sunny day? HDR signal.
Just like digital cameras, smartphones take multiple images one after another at different brightness levels, and then merge them into a single HDR image. The whole process is usually a breeze, taking a small fraction of a second.
(Image credit: Apple)
You may also have the option to select (always) on / off or auto HDR. Overall, Auto HDR does a great job, eliminating the hassle of manually applying the effect. However, it is also useful to have the manual option if you want creative use of exposure or to avoid ghosting in fast-moving subjects.
Some smartphones are listed as having HDR when in reality it is a highlight and shadow compensation feature, not true HDR. For example, Google Pixel phones use light and shadow sliders so you can lighten or darken those areas, but not technically extend the dynamic range.
How to make HDR photos1. Stabilize the camera
Whether you’re using a camera or a smartphone, the first step in HDR photography is to stabilize the camera. A shaky camera for HDR photography can result in blurry images. (It’s a similar principle to why it’s best to avoid fast-moving subjects in HDR photography, due to ghosting.)
(Image credit: Nikon)
Ideally, fix your camera on a tripod or stable stand, at least steady your hand. If you’re really going to town, activate or delay the camera’s remote timer to prevent camera shake from pressing the camera buttons.
2. Select the exposure parameters
With a multi-shot HDR or exposure bracketing mode, you can usually select how much to increase the dynamic range on one or both ends of the highlights and shadows.
However, you don’t need to use all of the images in the sequence when editing, so there’s no harm in maximizing what’s possible. However, it is best to get the “exposed for highlights” midpoint image using the histogram which is a good rule of thumb for single shot images.
(Image credit: Fujifilm)
If you are doing manual exposure bracketing, make sure that it is the shutter speed rather than the aperture that changes value. If you choose the latter, the depth of field will be changed and merging the images will be problematic.
3. Merge the images
There are specialized HDR software options for editing those bracketed exposure images, such as Photomatix. But even greats like Adobe Photoshop have this option.
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An example of an HDR photo using Photoshop’s “Merge to HDR Pro” feature. (Image credit: future) Image 2 of 4
HDR Off + 1EV (Image credit: Future) Image 3 of 4
HDR off 0EV (Image credit: Future) Image 4 of 4
HDR Off -1EV (Image credit: Future)
The simplest method with Photoshop is to select File> Automate> Merge to HDR Pro, where you are asked to import the sequence of images taken at different brightness values.
(Image credit: Future)
You can check the “Attempt to automatically align source images” box and press OK. Once the images are processed, the “Merge to HDR Pro” editor opens and the fun begins.
4. Edit the effect
The HDR editing process is very simple, but that doesn’t mean you have to accept the first automatic bid. Merge to HDR Pro includes all imported images and if you selected + 3EV at the time of capture, the effect may be too strong.
(Image credit: Future)
There is some leeway for manual intervention if the HDR effect is too strong. Try deselecting one of the images, reducing the saturation and so on, until you are satisfied. There is also a “Remove Ghosts” option which will attempt to address any movement in the scene.
As we said, the overdo usually occurs when the shadows are too bright. All in all, HDR works best when it reveals details in a subtle and natural way, but every artistic effect is subjective.
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