By Joseph Eckert.
HDR, or High Dynamic Range, photography has become something of a pariah in many photographic circles. Some photographers continue to use HDR to great effect; some continue to (according to some) heavily overuse it; and still others roundly criticize any and all who use HDR as individuals who are responsible for the systematic destruction of photography as an art form.
Traditional HDR is achieved by taking a series of bracketed exposures and then combining, or “tone mapping,” those exposures into a single image that has a greater dynamic range than any one exposure could by itself. For example, you might set your DSLR to take a bracketed series of 5 images at -2 EV, -1EV, 0 EV, +1 EV, and +2 EV. On combining those images in HDR software such as Photomatix, Nik’s HDR Efex Pro 2, Oloneo PhotoEngine, or even in Photoshop’s HDR module, you are given an image where you, in theory, get the best of both worlds – highlights aren’t blown out and dark regions aren’t masks of black. You have detail in both regions.
That was the goal of HDR in the beginning: provide a higher dynamic range than modern digital cameras can capture. The best of the best digital cameras right now – such as the Nikon D800 or some medium format back cameras – still don’t match the human eye in terms of the dynamic range they can capture. For a great discussion of dynamic range and a comparison to the human eye’s capabilities, check out this article on Cambridge In Colour.
But HDR comes with drawbacks. Chief among these is the so-called “HDR Look.” This look is characterized by heavy saturation of colors, strong “haloing” along high contrast edges (such as the horizon on a landscape shot), and a general sense of unreality to the image. The photo becomes painterly or “hyperreal.” Some people love the look. Many, however, are tired of seeing it on photo sharing sites and blogs.
It is important to know that the “HDR Look” is not a prerequisite of the HDR process. It is a characteristic of over-processing, of pushing the tonemapping and detail algorithms to their limit. As artists, photographers naturally did just that when HDR was new and exciting – pushed the limit. But as time goes on and the over-processed look becomes stale, it’s worthwhile to look back at the original intent of HDR and see how it can be subtly used to produce outstanding images that most people won’t even realize are HDR. In effect, you can use HDR to achieve a look similar to what photographers have been using layered, masked multiple exposures to get for years with Photoshop, or, going further back, what neutral gradient filters have been used to create for decades. Just without the digital layers or physical filters.
In this tutorial, I’m going to use the Nikon D800E for my example camera and Oloneo’s flexible and powerful PhotoEngine for processing, primarily because I’ve gotten good results from this combination, even with a single RAW exposure. But similar principles can be applied to almost any modern digital camera and software packages like Photomatix and Nik’s HDR Efex Pro 2 (for many cameras, however, the dynamic range will not be as great as the Nikon D800E; therefore you may still want to exposure bracket your images before tonemapping them).
The Nikon D800E is a new camera for me, and I’m still getting used to its many functions and features. As noted above, however, one huge benefit of the camera is its very large dynamic range. DXO Labs, an independent analyzer of cameras and lenses, actually lists the Nikon D800 as having the largest dynamic range of any camera it has ever tested at 14.4 EVs – greater even than the spectacular, and spectacularly expensive, Phase One IQ180 medium format digital back.
With the greater dynamic range of this new camera, I began experimenting with taking a single RAW file and seeing just how far I could press it. Could I get sufficient dynamic range from a single RAW from this new camera? Or would I need to continue to exposure bracket most of my shots, and end up having to save 5 exposures for every single high dynamic range photo I want to take?
I’ve found, with the help of Oloneo’s Photoengine, that for around 90% of my shots, a single RAW file from the Nikon D800E does, indeed, have sufficient dynamic range to give me the look I want – while avoiding the overprocessed and dreaded “HDR Look.” For those other 10% of my images, I’ll still need to exposure bracket if I want to fully exploit the dynamic range of the scene – I’ve found this mostly in shots with a lot of blank, empty sky and a very dark, shadowed landscape below, such as on the eastern side of a mountain, facing east, nearing sunset (with the sun behind the mountain but the sky beyond the shadow still very bright).
Here’s the process I’m using for the 90% case.
I have the D800E set up to capture RAW files, at 14 bits. I use the lossless compression setting to save a little harddrive and CF card space, and, since it’s lossless, I don’t have to worry about losing information during the compression. As you will no doubt hear time and again, I heartily recommend shooting RAW all the time for serious photographers, because you simply capture more usable data and have the ability to make critical decisions in post, instead of having the camera (or, rather, the camera’s programmers and engineers) make those decisions for you.
I have had better luck “exposing to the left” (underexposing or exposing the sky properly in a landscape shot and leaving the ground darker) with the process I outline below, so I keep that in mind while out shooting. However, every scenario is different and will require some experimentation on your part.
Once the RAW file is on my computer at home, I open it in Oloneo’s PhotoEngine. This is still a somewhat lesser-known program that deserves some more recognition. It struggles vs Photomatix when it comes to ghost removal and alignment of multiple exposures, but in this case, with one RAW file, ghosting and alignment are non-issues. Additionally, Photomatix currently doesn’t let you tonemap directly from a single RAW the way Oloneo and Nik’s HDR Efex Pro 2 allow you to do (in order to tonemap a single RAW in Photomatix, you’ll need to open the RAW in the RAW editor of your choice, save off a 0 EV version with a saved preset of settings as a JPEG or TIFF, then re-open the RAW two more times and save off a -2 EV and +2 EV version with otherwise the same presets; then open those three files in Photomatix).
Oloneo comes with a number of presets for the settings. These are all fine, but I recommend playing and creating your own settings. Pay particular attention to the top two settings: the TM (Tone Map) Strength and the Detail Strength sliders. These two settings are going to go heavily impact how “HDR” or “normal” your shot is going to look. I’ve found a rough sweet spot for these sliders at 62 for Tone Map Strength and 10 for Detail, but I play with these for nearly every shot to find the settings that work best for a given image.
Note that with Oloneo you can easily get the hyper-real, heavily stylized “HDR Look” if that’s what you are going for, just as you can with Photomatix or any other tonemapping program. But that isn’t what I’m after in this tutorial.
I’m going to provide a full list of the settings I use right now in Oloneo for one of my presets. I rarely see other photographers sharing settgins this way (without making people pay for them), but I’m comfortable doing it in this case because I’m confident you are not me; even if you had a Nikon D800E with the same lens and were standing right next to me in the same place for a shot, and we both processed using Oloneo and this preset, we would both end up with vastly different results, because we are different people with different photographic instincts and artistic priorities. Instead, I’m giving these out in the hopes it will help some other aspiring photographers. Maybe someday you can send me your new presets for me to try out!
Oloneo PhotoEngine 1.1.400 Preset Settings:
Advanced Local Tone Mapper:
- TM Strength 62
- Detail Strength 10
- Auto Exposure checked
- Exposure 0
- Fine Exposure 0
- Auto Contrast checked
- Contrast 10
- Detail Size 124
- Detail Threshold 75
- Edge Sharpen 0
- Panorama mode unchecked
- Natural HDR Mode – try it checked and unchecked
Low Dynamic Tone:
- Exposure 0.10
- Brightness 0
- Contrast 33
- Linear Raw unchecked
- Saturation 93
- Temperature “As Shot” to start
Photographic Print Toning unchecked
The rest of the Advanced stuff you can tweak on your own
Again, I play with the settings on a per-image basis. But it certainly helps a great deal to have a saved preset as a baseline to start from. Essentially, use the real-time processing engine that is a great hallmark of Oloneo and tweak until you get something you like. Note that I personally set the sharpening to 0 in Oloneo because I own Nik’s Sharpener 3.0 and I prefer to use it, with Photoshop’s layers and masking abilities, instead, on the JPEG Oloneo outputs. That gives me more control and lets me avoid sharpening things that I don’t want sharpened, like luminance noise, or clouds.
What are the drawbacks of the above process? I’ve noticed the output has higher noise, especially in the highlight areas (such as the sky), particularly when compared against processing the same RAW file in something like Adobe Camera RAW. Of course, I can’t get the same level of dynamic range out of the file with Camera RAW – close, but not the same, and the contrast and colors that come out of Camera RAW when I try never quite end up as vibrant and compelling as with Oloneo.
I’m not a software engineer but my guess is pushing and pulling the RAW file so much, as Oloneo does to eek out that dynamic range, produces artifacting in the form of highlight noise. I’m able to wipe out that highlight noise in Photoshop easily enough using Topaz’s DeNoise on a layer copy (masking out the darker portions of the image that aren’t noisy so I don’t lose image detail) – any decent denoising program (Noise Ninja, Nik’s Dfine 2.0, etc) should be able to do the same. But it is still something worth bearing in mind.
The larger drawback would be those 10% of shots that don’t work, as I mentioned above. If you completely clip your highlights, they will be clipped even with Oloneo’s processing. So if you find yourself in an extremely high contrast scenario, you will still want to bracket your exposures and then tonemap as you would have in the past. To determine where this contrast limit is with your camera, well, you’ll just have to experiment.
But, hopefully, in a large amount of cases, you’ll be able to get great results using a single RAW file with the process I’ve detailed above. Get to know your camera and experiment with how far you can press the dynamic range in programs like Oloneo PhotoEngine. You may find you don’t need to bracket your shots and mess around with layers and masks or traditional HDR tonemapping in order to get the look you want. And, in the process, you’ll save on SD/CF card space and reduce the number of cycles on your camera’s shutter – so you can take more photos, and fewer exposures.
As always – get out there and shoot.