We’ve all been there…you take a photo of an amazing sunset or other cool scene, but once you look at it afterwards on your computer you’re completely underwhelmed at the result. This typically happens because of user error, which stems from either overexposing or underexposing the image. Sometimes you can fix the issue in post-processing with software such as Adobe Photoshop, but even then, it more than likely still won’t look like what you remembered. Here’s the issue…most digital cameras on the market today can only capture anywhere from 10-14 stops of light, whereas the human eye can see a dynamic range of about 24 stops of light. To put it in easier to understand terms, a stop of light is a measurable value that refers to the change in the amount of light that is visible. When referring to cameras, every stop doubles the amount of light hitting the sensor. This is also known as aperture or f-stop. A lens with an aperture of f/2.8 (larger) allows much more light through than a lens with an aperture of f/22 (smaller). The larger aperture rating (f/2.8 in this example) is more important, because it means it can take photos in lower light scenarios. Our eyes work in much the same way. So what does this all have to do with your pretty sunset photo not looking the way you saw it? Simply put, camera sensors are unable to process all the highlights, mid tones, and shadows in an image equally. That’s where HDR photography comes into play.
High Dynamic Range (HDR) Photography is the process of shooting multiple, bracketed images of the same scene, and then merging them together during post-processing to get a better representation of what you actually saw. The process itself is rather easy, especially if your camera can bracket images. Most of the HDR images I shoot are three images stacked together. The first image is what the camera deems as the correct exposure for the scene, or the 0 EV (Exposure Value) exposure. The second is a +2 EV, and the third is a -2 EV. Here’s how it’s done. You first need to set your camera on manual mode (M). Next, you will want to adjust your exposure for what your first image will be (0 EV), and once that’s done you then need to select the bracket (BKT on Nikon DSLRs) setting on your camera and set it to 3F (3 frames). Once that’s done you’re ready to shoot, and although I would highly recommend using a tripod, it’s not completely necessary. Using a tripod will make it much easier to stack the three images together later.
Once you have your three source images (0 EV, +2 EV, -2 EV) you will then load them into your choice of photo software program. Although there are several HDR software programs to choose from, I would recommend using either Adobe Photoshop, Photomatix Pro, or Aurora HDR. They all have their strengths and weaknesses, and there’s no wrong choice. For many years, I used Photomatix Pro for my HDR images, but recently I have moved over to using Macphun’s Aurora HDR because it is has a great user friendly interface and is easy to use. If you’ve never had the opportunity to try either I would highly recommend downloading a trial version of each to see which one works better for your workflow.
Below is a screenshot of the Aurora HDR home screen. You have one of two options: Load Image(s) or Batch Processing. Batch processing allows you to take a large group or folder of bracketed images and process them all at once. You can also process a single image into a faux HDR with good results. In this case, we are only going to drag our three bracketed images into the window to start the process.
These are my three source images, which were shot at Arches National Park a few weeks ago using a fisheye lens. As you can see, one looks good, one looks overexposed, and the other looks underexposed. I always click the checkbox on the lower left for Alignment, because it saves me the extra hassle of doing it later on. You also have the option to reduce ghosting, which is a side effect of HDR processing that creates a halo around some objects. You also have the option to remove green and purple fringing (chromatic aberration), which occurs from color shifting in brightly lit scenes.
These images only took about 30 seconds for Aurora HDR to process. Shown below is the rendered image within the workflow window. Here, you have the option to do all sorts of tweaks to fully customize how your image looks, just like in any other photo processing software. You can also use several HDR presets, and change the opacity of each so that if the image is too over the top you can tone it down. HDR photography can be as realistic or unrealistic as you want it to be…that’s the beauty of it.
And voila! Here is the original correct exposure on the left, along with the bracketed HDR version on the right. As you can see, the HDR version has way more detail and has a nice exposure throughout the entire image. There is much more detail in the rock face, and the harsh shadows now have detail. The light spikes from the sun are more prominent, and the cloud detail is far more dramatic. Not bad!
I hope you found this week’s blog to be informative. HDR photography is a great way to get more detail out of your images, and allows an endless amount of creative options. And remember, if you can’t bracket images you always have the option to use a single source image to create an HDR effect with the right software. Feel free to leave me any feedback, comments, or questions below. Don’t forget that you create a login at the bottom of the page to save your favorite images, add yourself to our mailing list, and receive updates on new photo shoots and projects.