Getting around the limits of dynamic range
One of the challenges facing photographers is the limited dynamic range available in their camera's digital imaging sensor. Dynamic range describes the range of tones in a scene that can be effectively captured by your camera's sensor. Some sensors are better at capturing a wider range of tones than others.
Regardless of the capacity of your camera's sensor, you will come across scenes which have a dynamic range that is much wider than what your camera can capture. What you get, then are blown out highlights, or crushed, black shadows -- neither of which is good news.
Scenes that may pose a problem are usually backlit scenes -- where you have a very strong source of light (eg. the sun) in the frame, that affects the way your camera then exposes for the scene. Typical examples include trying to photograph the sunset while also retaining exposure of your foreground or midground, or taking a photograph of an interior scene but also wanting to retain exposure of the outdoors visible through a door or window.
A single frame exposure (left) of the scene leads to an underexposed foreground; exposing for the foreground (right) leads to an overexposed sunset.
When faced with scenes like this, you'll need to take multiple frames, each one at a different exposure (called "bracketing exposures"), and then fuse or blend the exposure to combine the exposures into a scene that better represents what our eyes see. There's software available to help you do this -- from those that automate the process (such High Dynamic Range - HDR - software) to software that lets you manually work on blending the exposures using the content from the differently exposed frames (such as Adobe Photoshop CC).
In this video, I demonstrate one of the more popular automated processes -- using an application called Photomatix Pro -- to fuse the exposure and allow me to further work on the image in Lightroom. An important take-away from this video is an understanding of how the different exposures of the same scene capture information in the highlights, midtones and shadows, and how fusing the exposures allow us to create an image which has a much wider dynamic range than could ever be captured in a single frame.
The scene is stunning sunset overlooking the old harbour at Maratea, a coastal town on the south west coast of Italy. What drew me to this scene was the rich hues of the sunset and the juxtaposition of the old town and the new boats in the harbour. Knowing what I know about the limits of dynamic range, I knew that I had to bracket my exposures and blend them later. I have also included the final, finished image in this post, following the video.
And here is the final image, finished in Lightroom and Photoshop: