What is HDR?


Standard photo


HDR and additional processing

If you’ve explored the camera app on your smartphone lately, you may see an option for HDR. This thing called HDR didn’t used to exist in smartphones, however. HDR was a technique of professional and some not-so-professional photographers years before it appeared in your pocket. So what is it?

High Dynamic Range (HDR) photography was the solution to complex lighting many photographers find themselves in. The resulting image from the technique represents something more like what our eyes see in a scene than the camera does. The difference is usually noticed in scenes with contrasting lighting, such has from within a canyon looking up at the sky — the canyon walls may be very dark while the sky is bright. The camera may only capture one of these two elements clearly while the other is left too dark or too bright.

The technique of generating HDR photos is done by capturing multiple photos of the same exact image, but at varying exposures. Depending who you ask, three to seven photos are required for a proper HDR photo. I generally only capture three — one underexposed to capture the details in the brighter portions of the scene, one overexposed to capture details in the darker parts, and one properly exposed to use as a base. It’s recommended to do this with a tripod as any shaking from your hands or movement in the scene can cause blurring or ghosting in the image.

Once you’ve taken your photos at varying exposures, your next step would be to load them into software designed to combine them into an HDR photo. There are many free and paid desktop applications for this purpose with Photomatix being one of the most popular. Lightroom 6 has also included HDR capabilities. These programs give you tools to control how your image will look. Most offer two methods of blending the photos together – tone mapping which generally produces colorful, surreal images or exposure blending, which give the photo a natural look. Just trust me in that a tone mapped HDR photo of a person tends to¬†look awful.

Smartphone approaches to HDR varies so greatly from phone to phone, app to app. From what I’ve witnessed, most, if not all, take two photos at varying exposures and use automated software to combine them. Smartphones likely capture just two exposures in order to remain speedy in capturing the image. Because multiple photos are being captured, you may not want to capture everything with HDR turned on. Anything that involved motion may result in the moving object ghosting in the image, which is where part of or all of the moving object(s) appear transparent or trail behind itself. It can also cause a double exposure effect such as the moving object appearing twice in the image.

Most often landscape or architectural photography turns out best with HDR photography. Other still photos would be ideal as well, but living things don’t always appear natural in the end result. In processing the photos with software, be experimental. This is a great way to learn and push your boundaries. However, many people over-process their HDR photos. Smartphone photographers usually don’t have to worry about this as the HDR processing is often automatic. Almost all artistic photos have been modified and many landscape photos are the result of HDR processing. The best ones are the ones in which you can’t even tell.

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