As nature photographers, we often find ourselves in front of a beautiful landscape scene with a wide range of tonal values. There might be shadowy rocks framing very bright waves in a beach scene. Maybe we are photographing a sunrise or sunset, where the sky is fairly bright but the landscape is not well illuminated. Scenes like these often require multiple exposure and HDR Photography techniques to create a spectacular landscape photo that you envision.
So how do we know when we can get by with one exposure or when we need exposure bracketing? This is a question I get asked a lot when working with students in the field.
Do I need Exposure Bracketing?
This discussion today is much different than what I would have written just a few years ago. We have seen such incredible advances in sensor technology. Today’s cameras can capture detail in a much wider range of tonal values than they could 2-3 years ago. So perhaps this discussion is even more important now.
Three years ago, I bracketed a lot of my landscape shots–better safe than sorry. My advice then was to just set your camera to bracket three shots, 1-2 stops apart and deal with it later. Today, I analyze the scene in front of my camera, check my histogram, and bracket when it’s needed. I have less culling and less work when I get home but I still know when to bracket in the field.
First, realize that you need to understand the histograms in photography in order to determine the need for bracketing for HDR photography. Kate Silvia wrote an excellent article on histograms just a few weeks back, so take a few moments to check that out if you need a refresher on histograms: A Beginners Guide to Histograms in Photography
Using Your Histograms
Now that you understand histograms, let’s look at how to use them in the field to determine the need for HDR. When I am setting up a shot in the field, I begin with a base ISO for the cleanest image. I choose an aperture based on my desired depth of field, often f8-f16 for landscape shots. I then set the shutter speed as metered by the camera and take a shot. Next, I check for the highlight warming alert on the LCD, telling me that I have blown highlights. I adjust the shutter speed just until I see the tiniest indication of blown highlights. This gives me the best exposure with the most data and no risk of having no data in the lightest part of the image.
Once I have completed these steps, I check the histogram of the last image. I know that the histogram will probably be more towards the right, where the most data lives, because I adjusted the exposure to allow for this. This is exactly what I want. Now, all I need to do is check the left side of the histogram for any indication that I have dark areas of the image with no data. If I find that I have climbed the left side of the histogram, thus having left those areas with no information, I know that I must bracket my shots in the field to get the full dynamic range of the scene. I will have a little work in post-processing, but I know I am going home with all the data I need to make a successful image with nice shadows and detail in the highlights.
Landscape Photos that require only One Exposure
First, let’s look at a RAW file and histogram that show me I can capture all the necessary data in one shot.
I determined an exposure that was as far to the right as I could go without climbing the wall of the histogram. I then checked the left side to be sure I wasn’t climbing. Note that both walls on the histogram do not show clipping, so I’m good with one shot.
Landscape Photos that require Exposure Bracketing
Now, let’s look at a scene that has too much dynamic range to capture in one image. Here is a real-life example of this process, from initial exposure determination through HDR. My first image of the falls is captured with attention to the blinking highlights. I get an exposure that will not blow out the water. But is one shot enough? Let’s take a look at the histogram:
I realize that I have done all I can to capture and maintain detail in the highlights of the image. But the shadows are definitely too far to the left of the histogram. Therefore, while I’m at the scene with my camera on the tripod, I take another image to increase the exposure and get details in the shadows. I increase the shutter speed and check the histogram to get the following image.
This second image has slight overexposure of the highlights but reveals good shadow detail. Therefore, in order to get good detail in both the shadows and the highlights, I will need to take more than one shot while at the scene and combine the exposures in post processing to create an HDR image.
Traditionally, I capture three images during an exposure bracket sequence. It’s easy to do a “normal” exposure for the highlights and then one stop over and one stop under that setting. When I get back home, I decide which of the three images I want to use and do an HDR blend in LR. I have found that using two images does a good job in LR. I rarely use the third one. While in the field, be sure to use your histogram to check that you have a highlight image that doesn’t climb the right wall and a shadow image that doesn’t climb the left wall. That will set you up for success with your HDR processing.
Here is the blended HDR photo right created in Lightroom:
I have had very good results with creating HDR images in Lightroom, with the added benefit of a RAW file to process.
After some work in LR and PS, here is the finished image. (I hate dead twigs! I am careful to clone or heal those out, especially when they intersect important parts of the image.)
Wrapping it Up
So that is my workflow, from start to finish. I am a very methodical photographer. I have formed what I think are good habits that allow me to make sure I go home with everything I need for a successful image in post-processing.
Hopefully, this helps you figure out when you need to bracket and do HDR and when one shot will be good enough. Get in the habit of using your histogram to determine the proper exposure and need for HDR and I think you’ll be happier with your images.