Dynamic range
Your eyes are amazing! They can take in a scene and cover a dynamic range of approximately 20 stops of light. So looking at a sunset, you can distinguish the light both around the sun and some shades on the ground at the same time! Your Nikon D4 unfortunately cannot. It can “only” cover around 12-13 stops of light, so if you have a scene where there is both some very bright parts and some darker ones and you’d like to cover the details in both ends of the spectrum, exposure bracketing is the tool to use.
Preconditions
With exposure bracketing, you are taking several images of the same scene at different exposure values. Perhaps needles to say, but you can only do this for stable subjects such as architecture or landscape photography. And you also need to make sure the camera is in exactly the same spot for the series of shots, and a tripod is the classic tool to make this happen.
As you are shooting a series of images, the easy way to get it done is to make sure your Nikon D4 is in continuous mode (low or high), so that it fires a series of shots when you hold down the shutter release. Otherwise you will have to hit the shutter several times to complete the series.
Finally, you need to give the camera some options for changing the exposure between shots and the semi automatic exposure modes like program, aperture priority and shutter priority are ways to secure this. You can also shoot in manual mode, but make sure the D4 has auto ISO set to on, otherwise there is very little for the camera to vary between the shots!
How to
You can bracket for many things such as white balance and also bracket using the flash light, but in this post I will just cover exposure bracketing using ambient light.
The wonderful Nikon D4 has a dedicated bracketing button sitting top left on the camera named “bkt”. If you hold down that button, you can set up how many shots you want in the bracketing series (3-5-7 etc) and also how many stops of light the exposure is to deviate from the normal exposure. Use the front and rear command dial to change the values. I usually set this to 1.0, but if you set it to say 0.3 or 0.7, you can select a larger number of images to be included in the series. If you set the number of images to 0, you are turning off the bracketing functionality.
Once you have captured a series of images, you will need to merge the images in post processing. I use Lightroom for this purpose, but there are probably other tools that can do exactly the samme. The software will pick the over exposed images to get access to the details in the shades and the under exposed images to get access to the details in the highlights, and by stitching the images together, a final image with improved dynamic range can be produced.