For those unfamiliar with the term, HDR (High Dynamic Range) is a solution to the problem of the camera not being able to handle the full range of tones in a scene. Often you may find that if you expose to record the foreground correctly, the sky is totally overexposed, but if you expose to capture detail in the sky, the foreground comes out far too dark. With HDR, you take three (or more) separate exposures – one “normal”, one underexposed and one overexposed. You then use specialised software to merge the three images into one. The software takes the highlight details from the underexposed image and the shadow details from the overexposed image to give you a photograph with full detail in both the light and dark areas.
For a number of years, the “go to” application for HDR has been “Photomatix” but in late 2015, a new kid arrived on the block in the form of Aurora HDR – a collaboration between software developer Macphun and HDR photographer Trey Ratcliff. The second version of the software has just been released, going by the name of Aurora HDR 2017, adding many more features, including batch processing and additional tools for tone-mapping and masking.
First off, you need to take your photographs. Obviously, it’s better to use a tripod, or at least a monopod to ensure your three (or more) images line up with each other, but the software does have a very good “align” function that compensates for small movements in the camera between shots, making it perfectly possible to still get excellent results from hand-held photos. Most cameras will have a feature that can be turned on from the menu called auto-exposure bracketing. This will automatically take three shots – one normal, one underexposed and one overexposed – in quick succession if you hold the shutter button down.
Once you have your photographs, they can be loaded into Aurora – open the three images simultaneously and Aurora will display them side by side. There is an “align” tick box at the bottom of the screen which should be selected if you want Aurora to align the photographs for you. This can be left unticked if you used a tripod but should be ticked if the photographs were taken hand-held. There are three other options that need to be considered:
Ghost Reduction – this should be turned on if there are moving objects (such as people!) in the photographs. If Ghost Reduction is turned on, Aurora will attempt to identify the movement and only use the middle exposure for that part of the image.
Colour Denoise – this tells Aurora to apply noise reduction to the darker parts of the image where the exposure is being increased. The downside to having this on is that processing the image will take a bit longer, but otherwise this can be left on all the time.
Chromatic Aberration Removal – this gets rid of purple or green fringes around the edges. Again, this can be left on if you don’t mind waiting a bit longer for Aurora to process the image, or it can just be turned on for those images where the purple / green fringes are noticeable.
When you have the correct options selected, you can click on the “Create HDR” button and let Aurora perform its magic. After a brief wait, Aurora will display the basic merged image on screen. This will probably appear rather flat and washed out, but this is just the starting point – now the fun begins!
Aurora comes with a large number of presets and it’s generally a good idea to try a few of these to see if one of them will give you a look that’s close to how you want the image to appear. The presets appear at the bottom of the screen, with a small thumbnail image to give a preview of what they each might look like.
The presets some in a number of categories – Basis, Realistic, Landscape, Dramatic, Indoor and Architecture, as well as some custom presets by HDR photographers Trey Ratcliff, Serge Ramelli and Captain Kimo. Some of these are quite surreal and need to be kept for the right image (and I don’t expect to ever find the right image for some of them!) some of them (particularly in the “Realistic” category) are quite good. Once you have found something you like, you can apply the preset and either stick with it as it is, or use it as the starting point for further adjustments. Aurora allows you to save your own presets for future use.
The main control panel includes a lot of sliders that will be familiar to users of Lightroom or the Photoshop Camera Raw plug-in, but a closer inspection reveals that they’re not just a copy – Aurora’s controls might be better described as “Lightroom on Steroids”!
Besides the usual exposure, contrast, highlights & shadows, vibrance, saturation and clarity sliders, there are numerous additional controls that allow you to adjust the colour tint separately for highlights & shadows, the level of detail, the image radiance, glow and the top & bottom lighting. The latter acts like a neutral density filter allowing the top & bottom of the image to be adjusted separately with the transition point being completely adjustable in size, position and angle.
The other main feature of Aurora is layers, which is something that will be familiar to Photoshop users. By using layers, it’s possible to have different settings for different parts of the image. You can have the basic image as the bottom layer and then add all the adjustments to an adjustment layer on top of the image, then add different adjustments to an additional adjustment layer on top of the first one. The layers can then be masked – which means you can paint on the layer to make that part of the layer “see through”. As an example, you may want one set of adjustments for the foreground and a different set of adjustments for the sky. On the first adjustment layer, you add the adjustments for the foreground. Then you turn that layer off and add a second adjustment layer for the sky. Turning the first layer back on will apply both sets of adjustments over the whole image. Masking off the sky on the first layer and masking off the foreground on the second layer will mean that only the second layer adjustments apply to the sky and only first layer has an effect on the foreground.
Whilst you should use multiple exposures for the best results, it’s quite possible to use Aurora to process a single image. Shooting in “raw” format is recommended if you do this as the raw file will contain the full highlight & shadow detail that the camera was able to record in the single exposure.
A comparison with Photomatix is inevitable – Aurora has more features, but Photomatix is noticeably faster. If you have a lot of images to process and time is of the essence, then Photomatix may still be the better option. This was particularly the case with the first version of Aurora which lacked a batch processing option, but Aurora 2017 now has batch processing and although it’s still slower than Photomatix, the speed has been improved from the previous version. For me, the additional options – particularly layers, which are totally lacking in Photomatix – are the deciding factor that has made Aurora my HDR software of choice.
Aurora HDR 2017 is currently available for Apple Macintosh only, but a Windows version is planned for Spring 2017. The software costs £78 to buy but a free trial is available for download from the website: https://aurorahdr.com