Have you taken a photograph of any landscape scenery and wondered why the sky is blown out? Or when your sky is properly exposed but your subject is too dark? This is where HDR technique comes to play in post processing.
According to Wikipedia, “High-dynamic-range imaging (HDRI or HDR) is a set of techniques used in imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques.” A camera has a maximum dynamic range that it can capture in one shot. A mid-range DSLR has an average dynamic range of 10-14 stops. What it means is the camera can capture the numbers of lights and darks in the picture with the range measured in stops.
In order to expand the dynamic range of the photograph, photographer will take several images of the scene in different exposures and merge them into one image. While merging, we will have the control of the brightness of the highlights of the sky and the darkness of the shadow. Therefore, it is called high-dynamic range image.
Example of a series of images taken for HDR processing:
Example of a HDR image:
As you can see HDR image can bring back textures of the clouds in the sky and the tiles on the bottom right of the image. Depending on the climate condition of the shooting time, technically it can be done with one shot. However, if you are travelling and you do not have much time to wait for the perfect lighting. HDR is your best bet.