SNS-HDR: An Easy Way to Get Natural Looking HDR Images
As I've written in another recent article, there are a lot of new applications for High Dynamic Range imaging available these days. If you're interested in natural looking HDR, you owe it to yourself to check out yet one more.
Some HDR applications tend towards the extreme, producing results that are more works of art than photographic images. Objects almost glow with oversaturation and halos. I've seen some such creations that look good but I'll have to admit I'm not a fan of most images of this kind. Personally, I like applications that help me get realistic results. All HDR applications will let you create realistic tone mapped images of course, but some make it easy, and some make it much more difficult. I really have better things to do than fight with software when other options exist. Two favorites I wrote about recently are the new Nik Software HDR Efex Pro, and the still beta Oloneo Photo Engine. Oloneo isn't yet very well known while everyone seems to be talking about Nik's offering.
This week, I want to let you know about a great HDR program that is even less well known so far than Oloneo. SNS-HDR is written by Sebastian Nibisz who lives in Poland. His website at www.sns-hdr.com is written in Polish. The program installs in English (with an option to change the language to Polish if you prefer), but the site itself is in Polish. There is a "Select Language" dropdown in the upper right corner to translate the text to English or many other languages, but be advised that this seems to work under Internet Explorer only, not Firefox. Or you can always use Google translator or any other online translation service manually with any browser. It's one of those cool things about the modern Internet that makes it possible for me to find a program like this and read a website like this. Once installed, the language difficulty is behind you so don't let this discourage you if, like me, you don't speak Polish.
SNS-HDR runs on Windows only and is available in three versions. The underlying engine is the same in all three, but the degree of control offered the user varies in each as does the price.
SNS-HDR Lite is freeware but runs from the command line only. It has no graphical user interface whatsoever. You might think that this severely limits its usefulness, but given that the program automatically tends towards realistic interpretations it still manages to produce surprisingly good results. There are at least some options available from the command line and I've been impressed with what is possible by leaving everything beyond this up to the program's defaults.
You can run the Lite version by simply dragging the source files over on top of the program icon in the directory where you installed it. SNS-HDR Lite will merge them with its defaults and write the resulting image as a jpeg to the folder the source files came from. This is somewhat unconventional for a Windows application of course, but for free it can be worth seeing what the Lite version does with what you shot even if you have other HDR programs. I suspect you will be pleasantly surprised as I was. You can also run it from the command line. Open a command window by clicking on the Windows "Start" button and typing "cmd" in the "run" or "search" box. Then change directory to the folder containing your source images. To run the program, type the full directory and path to the SNS-HDR Lite application followed by the name of each source image. If any have spaces in them just put the names in quotes.
Beyond the default rendition, the Lite version offers several other presets. To see the other options, run the program with no file names or other parameters. The "dramatic" preset does what you would expect by exaggerating local contrast yet still avoiding halos and other artifacts. The "ldr" preset (Low Dynamic Range) will give you only minimal shadow detail and minimal local contrast to produce results that look almost like you managed to get the shot without HDR. The "natural" preset seems to be somewhere between "ldr" and "default." There's also a "neutral" preset that is somewhat like "ldr." The oddly named "soft" preset creates results quite similar to "natural" but strangely not as soft as "neutral." Then there's also "night" and "interior" which offer subtle variations on "default." Without a user interface you will need to actually convert your images to each of these to see what they do. You will probably come to prefer one or two presets for different types of images though so it is unlikely you will really need to go through each preset in practice. I generally start with the "natural" or "ldr" preset.
By default, the Lite version automatically aligns source images and performs a de-ghosting algorithm, but these can be disabled with the "-da" and "-dd" command line switches. You can also turn on a panorama mode with "-pm." The Lite version lets you change the default jpeg output file format to either 8-bit or 16-bit tiff. Turn on another command line switch to automatically convert the output to sRGB. The program can convert many raw file sources using Dave Coffin's dcraw code but unfortunately using raw inputs seems to always result in sRGB output, forcing you to do your raw conversion as a separate step with another program and then feeding the intermediate results to SNS-HDR Lite if you want to retain a larger gamut than sRGB. SNS-HDR Lite can also shrink the image size to a few preset ratios but you will likely want to retain the original dimensions and resize with other means that allow more flexibility.
To the basic features of the Lite version, SNS-HDR Home adds a very flexible graphical user interface with one of the most comprehensive sets of tone mapping controls of any HDR application. The author licenses this version for 30 euros (about $42 USD at current exchange rates) for non-commercial home use only. SNS-HDR Pro has the same great user interface controls as the Home version and adds a batch processing capability. The Pro version goes for 85 euros (around $120 USD) and removes the non-commercial license restriction.
Either of the versions with a user interface obviously provides a dialog with a file chooser to allow you to select the source images to be merged. You also get to see thumbnails down the left hand side of the window of what each preset will do to what you are working on, and you can save your own presets if you choose. Down the right hand side of the screen you will find a great set of controls for affecting virtually every aspect of the tone mapping process. Apart from the Nik proprietary control points offered by HDR Efex Pro, nothing else comes close to what SNS-HDR offers for flexible tone mapping.
The onscreen view in SNS-HDR Home and Pro can make use of a color profile for your monitor but you will need to point the program to where the profile is saved. Most color management aware applications such as Photoshop can automatically find the right profile by asking your operating system, but SNS doesn't seem to be able to. So long as you keep the same name each time you re-profile your monitor, you'll only need to tell SNS-HDR where it is once. But if you change the profile name each time by adding a date or something you'll need to remember to keep the SNS settings up to date.
All the examples in the gallery section of sns-hdr.com are architectural images but it seems to do quite well with nature images too. Chromatic aberration along extremely high contrast edges I've found to be somewhat problematic but I believe this has more to do with dcraw than SNS-HDR itself. For situation like this, I can deal with the problem in third party raw converters anyway.
SNS-HDR is a hidden gem of a program that deserves to better known. It really does rank up there with the best HDR programs from other vendors. Highly recommended.
Update 3/20/2011 - Just as I post this, the author of SNS-HDR seems to have released a new version of the program. Version 1.3.9 now allows you to select the color space for images converted from raw formats. Thank you Sebastian.