What is HDR?
HDR stands for high dynamic range. The dynamic range is the visual “distance” from black to white. By making that visual distance greater, you create a wider tonal range in the image. The world we see around us contains far more range than can be reproduced on a monitor, printed to paper, or even saved in a 16-bit image.
Consider, for example, shooting an image in a room with windows on a sunny day. If you expose your image for the content of the room, whatever is outside is blown out and completely white. (See the examples shown.) If you expose for the outside, the content of the room is in shadow. So, why not create an image in which the content of the room and the world outside the windows are both properly exposed?
It may be that HDR is the future of photography, the way digital has supplanted film. But probably not, until we have cameras that can capture true HDR images natively (as some smartphones can), as well as a way to better take advantage of the enhanced tonal range when printing. Is HDR something about which you should be aware, so that you can take advantage of its potential to meet difficult challenges in your own photography? Absolutely!
Remember, too, that you can open a series of Raw images shot for merging to HDR and open them together into Camera Raw. Use the menu to the right of Filmstrip (near the upper left) to Select All and then Merge to HDR. You see a preview and the Align Images and Auto Tone boxes are selected. Try all four of the Deghost options to determine which works best with your images, and then click the Merge button. (If the images were shot properly, you likely don’t need the Show Overlay option.) Camera Raw generates a .dng file that you can further refine in Camera Raw if desired.