If you are like most photographers, creating an HDR image is like stepping off the edge in the world of the unknown. Taking the plunge doesn’t have to be scarry though, and in reality it can be a lot of fun!
In this article, I’ll take you through the steps to create an HDR image simply. By this I mean that I will keep the process simple and easy. So let’s take a look at the steps involved, and then discuss each of these steps.
1. Take a series of bracketed images of the same scene
2. Merge the series of bracketed images into an HDR image
3. Tone map the HDR image
4. Do normal post processing on the resultant tone mapped image
There they are, all the steps needed to create an HDR image in the simplest way possible. So let’s get started, but before we do maybe we should revisit or explain what HDR is. HDR stands for High Dynamic Range which simply means more tonal range that what your camera can capture in a single image. Camera’s today do a really good job of capturing tonal range, but they are limited in what they can do. Your eye can see about 12 stops of light, yet the best DSLR’s on the market today can only capture about 6-8 stops of light in a single capture. This is one reason why your pictures are disappointing and don’t look like what you saw. It’s not your fault, it’s the camera’s fault. It just can’t see what you see.
So if the camera can’t see what I see, then how do I capture the image I’m seeing? This is where HDR imaging comes to the rescue. With HDR Imaging, you will take multiple images of the same scene at different exposures, generally at -2ev, 0ev, +2ev. Canon cameras allow you to set these bracketing steps in camera, however, Nikon cameras only bracket in up to 1ev steps. So on a Nikon camera, you would bracket to take five exposures at -2ev, -1ev, 0ev, +1ev, +2ev. I’m not familiar with the other camera makes, so for you Sony, Pentax, or other camera makes you will need to refer to your users manual to learn how to set up bracketing. Anyway, taking a series of backeted images like this allows you to extend the dynamic range of the camera by four stops of light (two stops under, and two stops over the normal exposure range). So now instead of six stops of light with a single exposure, we have 10 stops of light through our bracketed exposures. If you wanted to extend the range to 12 stops of light, on the Nikon you would dial in seven bracketed exposures. The Canon cameras require some manual intervention though because they only bracket three exposures. How to do this on a Canon is beyond the scope of this article (I’m a Nikon shooter). The Nikon cameras can bracket up to nine images at 1ev stop intervals, more if less than 1ev intervals. Any way, I digress…
Step 1. Take a series of bracketed images of the same scene
To do this, you will need to set your camera up appropriately. There are two modes that work, aperture priority and manual. I recommend using manual mode, but this is a personal preference as either mode will work. You will need to set your base exposure (the 0ev exposure) as you would for any normal scene using which ever metering method you prefer. I prefer spot metering as I feel it gives me more control over the exposure. Then set your camera to bracket for the number of exposures you need to capture all the detail.
There are a number of ways to determine how many exposures you will need. One of the best ways is to use spot metering and meter the darkest area you want to retain detail, then meter the lightest area you want to retain detail in and calculate the difference between. If the difference was nine stops, then setting the camera for two over and two under will capture the entire range of the scene if your camera normally captures 6-8 stops of light. Just don’t forget to set the camera for the middle exposure or you won’t get the full dynamic range of the scene.
Before you press the shutter and capture those bracketed images, mount your camera on a tripod and use the cable shutter release. Doing so will ensure you get good sharpness throughout in your images. If you don’t have a tripod handy, set your camera to shoot continuous high speed and steady yourself as best you can. Take a deep breath in, then let the breath out slowly, then press the shutter to capture the bracketed images.
For this article, I shot five frames (bracketed images) on my Nikon handheld as seen here. I didn’t have my tripod handy when I came upon the scene.
As you can see, these images are nothing special to look at in this stage of the process. They are straight out of the camera – raw. That’s another thing I forgot to mention above, when shooting to do an HDR, always shoot in camera raw. Doing so will ensure you have all the detail to work with in the later stages of the process. Before anyone has a problem with this, yes, it can be done with a jpeg file, but you will get significantly better results with a raw image.
Now after I have captured the images, I will load them into Lightroom to organize, catalog, etc… From Lightroom I will select the five images and export them to Photomatix. There are a lot of HDR software applications out there and most will do the job really well. However, what I found after doing a lot of research is there is one application that stands out and is used by more professional photographers than any other HDR software application available. The HDR software application of choice by these pros was Photomatix. This is the application I use, and after comparing the results with several others, it has quickly become my HDR software application of choice. Besides, it integrates with Lightroom very well and makes my work flow smoother. So now it’s on to step two of the process.
Step 2. Merge the series of bracketed images into an HDR image
As soon as I select export to Photomatix, I’m presented with the following options:
When this dialog box opens, there are some default options already selected. Since we are creating an HDR image, the Generate HDR Image option is selected. It’s a good idea to make sure that the options to reduce chromatic aberations and to reduce noise are selected. Sometimes during the merge to HDR process additional noise finds it’s way into the image as do some aberations. With these two options selected, Photomatix will attempt to reduce both, and you will get better results.
The option to reduce ghosting artifacts is not selected by default. If you have any moving objects caused by wind, people, cars, etc… it’s a good idea to select this option. This option also has two sub-options. One for background movements, the the other for moving objects or people. I always select the option for moving objects or people. I’m not really sure why the background movements option is there or even what it does. I’m sure there is a reason, I just don’t know what it is and have not found a situation where I thought I might need this option. The next option tells Photomatix to go straight to Tone Mapping after generating the HDR. I will generally do this except in some instances where I might want to play around with different settings in Photomatix creating multiple HDR files of which I can blend together in Photoshop for some really cool looks. However, since most of what I do is to generate the most realistic and natural look, I will leave this option selected and let Photomatix go directly into tone mapping after generating the HDR file.
The next option is for alignment of the bracketed images. My suggestion, always, always, always select this option even if you used a tripod. The end result will be much better if you allow Photomatix to align the images. Here again there are two options, select the option that fits best with the type of images you are asking Photomatix to align. For the types of images I do, I have found that the option for matching features gives me the best result.
The other options deal with file naming and how the file should be reimported into Lightroom when the HDR file is created. Always select 16 bit tiff for your file size option as this will maximize the detail that is created.
A note on the stacking option. I used this when I first started using Photomatix and quickly got frustrated. It is not a fault of Photomatix, it is a Lightroom option which will stack the created HDR image with the first image in the bracketed series. For some this might work, for me, I found it to be an exercise in frustration trying to get back to the HDR image I just created. I know it is just me, so experiement with this setting. If you don’t select it, the HDR image is reimported and displayed in Lightroom as the image before the first image in the series. Ok, I know, it’s just me and I don’t work well with the stacking option in Lightroom. It just doesn’t fit into my work flow.
Once the options are set, I click on Export and let Lightroom export the selected images as tiff files to Photomatix. Once Photomatix opens, it will automatically load the tiff images and generate the HDR image. If I left the option selected to go straight to tone mapping my HDR image will open up in the tone mapping screen, which takes us to the next step. See this isn’t that hard, is it?
Step 3. Tone map the HDR image
In this step we have a lot of options available to us, and the number of options and sliders can be overwhelming. However, the good folks at HDRSoft have provided some presets to help us out.
You can see at this stage the image is nothing spectacular. In fact it looks rather washed out and not a lot of contrast. That’s ok though, we’ll fix that later. What we need to do at this stage is to make sure the tone mapping is able to compress the vast amount of information available in the HDR file down to a manageable file that can be displayed on the screen and printed.
Since I want this image to look natural and realistic, the first thing I will do is select the natural preset from the list of presets. The result of this selection is what you see in the example image. The only other thing I will do here is to adjust the strength slider up to around 70 which gives a richer, deeper look to the tone mapped image. When you’re at this stage with your image, I suggest you move each slider and watch what it does. This seems to be the best way to learn what the sliders do. The main sliders I work with in the tone mapping screen are the strength, Microcontrast, and Smoothing. Sometimes I will adjust the Luminosity when I’m seeing the halo effect, but most of the time I will just click on the natural preset then adjust the strength slider to my liking.
Even though you can create a fully finished product in Photomatix, I have found it easier to let Photomatix do what it is really good at – which is merging multiple images into an HDR file, and let Lightroom or Photoshop do what it is really good at – which is adjusting color and editing. So again, for most of my images (and the one shown in this article), I will select the natural preset, increase the strength to my liking, and click Save and Re-import to finish up the editing process in Lightroom and/or Photoshop. For more details on tone mapping in Photomatix, watch the tutorial and refer to the HDRSoft support and documentation. Additionally there are literally hundreds of articles and documents on how to use Photomatix. Do a search on Google and you will find plenty to read.
Step 4. Do normal post processing on the resultant tone mapped image
Once I have the tone mapped image back into Lightroom (and it doesn’t look all that good yet), I will start to apply a standard set of adjustments which will have a dramatic effect on the image. The first is to adjust the exposure. This is only needed if the right edge of the histogram is not touching the border of the histogram box, and this is image dependent. You may not want to adjust the exposure. The second adjustment is that of black clipping, this will cause the left side of the histogram to come in contact with the border of the histogram box. This adjustment is almost always needed, and when you make this adjustment you can watch the washed out look give way to a rich and colorful image. These two adjustments in Lightroom are the same as doing a Levels adjustment in Photoshop.
The next adjustment is to add in some vibrance and clarity, then do a tone curve to increase contrast just a little. After that, what adjustments you make are pretty much a matter of taste, but up this point, this is all you need to do to create an HDR image in as simple a way as possible.
For my example image, I cropped it a bit to raise the horizon line to the third line, added a gradient to both the top and bottom of the image to enhance the color, then dodged areas in the trees where the gradient made it too dark. This last step was done in Photoshop. The resultant image looks like this:
That’s all there is to it! Hope you enjoyed this article.
Update: The good folks at HDRSoft have provided a coupon code for readers of this site to receive 15% off on their purchase of Photomatix. Just enter the coupon code “HDRPhotoZone” in the coupon box at checkout! Many thanks to HDRSoft!