There’s no doubt about it, HDR imaging has shot a real bolt of energy into the digital photography scene. With the breathtaking images that HDR techniques enable, even the most hardened analogue photographers have been heard to say ′ahh, so that’s what digital is for′. But while no high-end commercial photo package is, these days, without its High Dynamic Range tools, HDR isn’t just for the professional, or the big-spender. There are a ton of free HDR applications out there now, offering HDR creation, alignment and tone mapping.
But in a field where appearances are all, your free HDR utility doesn’t just need to be work-a-day – it needs to bring out the superlatives. So below you’ll find only the best of free HDR software, apps that will help turn the reaction to your photographic images from nods to gasps. And not a watermark in sight.
Creating HDR images is a two-stage process. By taking a number of fixed shots, within a bracket of exposure settings, the whole brightness spectrum is covered in depth. Your HDR software is then used to merge these images, using the best exposure, from the lightest to the darkest parts of the photos. The problem then is to get all that wonderful detail displayed – because most computer monitors simply cannot handle all that additional tonal range. That is where tone mapping is essential. And tone mapping is something that Essential HDR excels in.
It has a simple light-touch interface, that allows you to control the tone mapping in detail, through color balancing and histogram adjustments. Two tone mapping algorithms come out of the box – Fast Tone Balancer and Detail Releaver. Both are, in fact, pretty fast, and the results are generally excellent. As well as tonal mapping, Essential HDR also does a decent job of aligning shaky hand-held shots. The big problem with Essential HDR – in this free version at least – is the 1 Megapixel limit on input files. If you want to preserve to the totality of your original picture, that may be a sticking point.
Luminance HDR is an open software package that spans Windows, Linux and Mac OSX systems, and works well for those looking to dabble in new approaches. Formerly known as Qtpfsgui (back in its Unix days!), this is a tool developed by photographic nerds for photographic nerds. Both auto and manual image alignment are included. It takes RAW input files, and also handles a whole bucket load of HDR formats (like PFS, HDR, EXR and TIFF) as well as the usual fare of LDR formats (like JPEG, PNG and PPM).
But it is with the tonal mapping that there is a feast of plenty. Luminance boasts nine tonal mapping algorithms, some of which lend themselves towards being used as effects filters. The interface does remain rather sticky and confused, just like in the Qtpfsgui days. And there is a lack of a proper real-time preview, which is only partly fixed by the cut-away preview tool. There’s still plenty to like with Luminance HDR – but maybe it needs a bit of a tidy-up, to keep it up with the pack.
The freeware version of this tool, from German software company AGS Technology, is another excellent candidate for transforming your badly-exposed and bland digital stills into something that little bit special. As with the other HDR programs looked at, it is setup to load a bracket of photos taken together, and pool them into a new HDR image. So there is an auto-adjuster for the alignment of your brace of photos, which you can fine tune manually.
It comes with a couple of nice tonal mapping processors, which cover, between them, adjustments to the color histogram, saturation, compression and gamma – as well as brightness. Apart from the usual TIFF and RAW inputs, you can pull in OpenEXR and Radiance RGBE formats. And Radiance and OpenEXR are covered on the output side too. The resulting HDR images come out well, although some users complain of a tendency towards ‘plastic’ looking outputs. Perhaps HDR beauty is in the eye of the beholder.
While the preceding tools are good, Picturenaut is a free photo-editing tool that takes HDR processing to the truly professional level. It impresses straight away with its snappy interface, and fire-and-forget processing. That comes from the fact that Picturenaut has teased the interface away from those tasks that are more time-consuming. So you are free to carry on with other work, while tonal mapping or alignment goes on in the background. And that processing is lightning fast too – making the whole process of generating tonally-mapped HDR images a real pleasure.
Picturenaut also has a broad range of features, ones you might expect to see in a high-end commercial app – such as ghost removal and noise level compensation. It does, of course, support all the input file formats you’ll have heard of – and several you won’t – including the RAW outputs of most digital cameras. It also has real-time previews, and the HDR images that it spits out rank very highly for their natural-yet-stunning dynamic response. Niggles include the lack of manual alignment options, and an inability to write out JPEGs. But you’ll be hard-pressed to better Picturenaut 3, when it comes to free HDR software on Windows.
But what about the Mac I hear (some) of you ask? Well, as you might expect from the home of all those creative-types, the Mac has plenty of HDR functionality in its commercial photo-editing suites. But freebie HDR software is catered for too. In addition to Luminance HD (described above), there is HDRtist. OK, it’s not the most complicated piece of software out there – but it takes what can be a technical and involved process, and makes it simple and fun. It can process single RAW files for HDR images, as well as the more usual multiple-image input route.
Image alignment works fine, although it is not as good as some already described. The tonal mapping is about as simple as it gets – you just slide a single control, to adjust the ‘strength’ of the tonal merging. But if you want to to make HDR files quickly, and are not too fussed about getting perfect results, HDRtist will get you there fast. And a big chunk of photographic content comes from less-than-top-spec smartphone cameras, these days. So, getting too fussy over the finer details of processing can be pointless in many cases – making HDRtist a perfectly good piece of HDR software for the Apple masses.