Photographing a high-contrast or backlit scene can be challenging. Do you expose for the shadows and blow out the highlights? Or do you expose for the highlights and lose everything in the shadows? It really just depends on your personal and artistic preference.
Software like Lightroom is able to do a lot when it comes to fixing a photo that is either over or under-exposed. You can use the highlight slider to take down the highlights and bring back some detail. With the shadow slider you can lighten the shadows to get more detail. But if you take those sliders too far it can make the highlights gray and the shadows noisy.
Another solution to the problem is to create an HDR image.
What is HDR or High Dynamic Range? Dynamic Range is the variation from the brightest highlights to the darkest shadows in a scene. When we look at something, our eyes see a much wider range of light and dark than a camera can capture. By using HDR in post processing, we can create an image with more detail in both the highlights and the shadows and that is much closer to what the eye sees.
One of the best uses for HDR is for photographing architecture, especially interiors. If it’s bright and sunny outside the camera will either expose correctly for the shadows and blow out the highlights, or expose correctly for the highlights and lose details in the shadows.
Another scenario where HDR photography works well is landscapes. Just like with interiors, when it’s not possible to get the correct exposure in the sky and in the terrain at the same time, combining several exposures into one can have much better results. That’s one of the greatest benefits of HDR—the additional details. The important thing is to balance the increase in detail with a realistic view of the scene.
Backlit or high contrast scenes can benefit from using HDR as well. Keep in mind that if there’s movement your camera shutter speed will need to be fast.
Some people dislike HDR because they have only seen it when it’s very overdone. If it’s over-saturated, hyper-realistic or blurry it’s very unappealing. Some shadows and highlights are necessary in order to perceive depth. When it’s done right, it can be beautiful. Take a look at Trey Ratcliff’s portfolio to see some good examples.
Here is a before and after of what I will be explaining.
To create this HDR image I’m going to choose three photos. One that is over-exposed, one in the middle and one that is under-exposed.
The best way to know if an image is over or under-exposed is by looking at the histogram. The histogram is a rendering of all of the tonal values in your image. It goes from 0% on the left (black) to 100% on the right (white). In a balanced image the histogram won’t reach the peaks of zero or 100—when that happens details are lost.
In the Lightroom Develop module, the histogram has two arrows on the top corners that when clicked will show highlight and/or shadow clipping. Over-exposed highlight areas are shown in red and under-exposed shadow areas are shown in blue.
In the Brightest photo the room is well-lit, the way it looked in real life. But when we look at the histogram and click on the arrow on the right, it’s easy to see that the highlights are blown out. A lot of detail is lost both outside and in the chandelier.
The “middle” image shows the room better, but it’s still missing details in the highlights and we can barely see outside.
In darkest photo, we can see the garden outside the windows and the details in the chandelier, but overall the room is too dark. No detail is lost in the shadows, but it doesn’t allow us to visualize the space.
Lightroom makes creating an HDR image easy with the Photo Merge tool.
Begin with at least two RAW images taken with a tripod. JPG images won’t contain enough detail to be merged and any movement in the camera position will result in blurry images.
For best results, use a camera that has AEB (Auto Exposure Bracketing). That way it will automatically take bracketed exposures. You can do it by manually changing the camera settings, but doing so increases the chances that you’ll move the camera and get a blurry image.
Select all of your photos then click Photo > Photo Merge > HDR
Lightroom will create a preview of the HDR image. Auto Align and Auto Tone are selected as default—leave them that way. There is minimal ghosting on this image. That’s more common with HDR photos where there is movement in things such as clouds and trees.
After merging, open the new file in the develop module and, if needed, adjust the exposure, check for noise, and remove any chromatic aberration.
The final merged image shows details in the shadows and throughout the room as well as in the chandelier and the plants in the garden.