HDR: High Dynamic Range Masterclass
HDR photography can be extremely impactful if done correctly. Follow our HDR masterclass and produce stunning High Dynamic Range (HDR) images.
The world of digital photography is constantly evolving, with new and diverse techniques and treatments emerging in relation to what you can do with your images.
One of the latest and most popular of these techniques is HDR, or ‘High Dynamic Range’, processing, with nearly a quarter of a million images on image-sharing site Flickr possessing the tag ‘HDR’, and top-notch examples of the technique creeping more and more into the modern photographer’s repertoire.
As with most new techniques, HDR can seem intimidating at first, with the initial steps to creating top-quality HDR images being the hardest. However, WDC is here to help make these steps easier.
Benefits of HDR: High Dynamic Range
As can be seen by the various examples on these pages and the plethora of images creeping into the photographic community, HDR is an unarguably eye-catching technique. However, there is more than just an artistic purpose to the technique: it can be used as a practical tool to improve your photography.
As previously mentioned, the HDR technique allows the photographer to display the full dynamic range of an image, revealing detail that would otherwise be lost in shadows and highlights. The technique also uncovers a wider range of tonal details that, while visible to the eye, cnnot be captured in a single image, which is likely to feature blown out highlights and murky shadows.
The practical implications of the HDR technique are best illustrated by the following example.
Imagine taking a photo from the inside of a room and attempting to obtain an accurate representation of both the room and, say, the fantastic view through the window.
Capturing such a scene using a single exposure would be almost impossible due to the huge difference in brightness levels between the inside of the room and the outside. The problem would be the same if you were shooting shadowy architecture, for example.
The beauty of HDR photography is that such a problem is easily overcome, thanks to the ability to blend and tone map several exposures of the same shot where both the shadows and the highlights have been exposed correctly. In our example of the room, you would be able to maintain the detail of the interior while also showing the view through the window.
Art as Well as Craft
As with other photographic techniques, there are also artistic implications to HDR processing. An editing suite such as Photoshop presents the photographer with a range of filters which provide the opportunity to completely transform an image. The results can be impressive and, if used correctly, can enhance the quality of an image dramatically. It is worth noting, though, that just because a lot of filters are on offer, you don’t have to use them all, and to their fullest capability. Many a fantastic photograph has been spoiled by over-adjustment.
The principle is the same with HDR. A broad range of postproduction tools exists, and their use often produces surreal and unusual results, which can be to some people’s liking but not to others. The key is to gain an understanding of each individual tone-mapping facet and then to learn how it can be used to most accurately achieve the effect you’re after. If you don’t have an understanding of each facet, then you’ll struggle to find a good use for the technique.
When you come to decide exactly the kind of effect you want from your image, whether it be an adaptation of a difficult dynamic range in a shot, the urge to recreate the drama of a storm, or just a new approach to portraiture, the HDR technique offers something for everyone.
No Miracle Cure
While HDR might present you with a whole new range of postproduction challenges and tools for image manipulation, it is crucial to remember that the fundamentals of photography are still as important as ever.
After all, while HDR has the ability to transform a good picture into an excellent one, it isn’t a miracle cure for a bad picture, though it is often misused as such, with horrific consequences! Here are a few helpful things to bear in mind:
HDR Composition and the ‘Basics’
One of the most important ingredients of any good picture is composition, and this is no less true of HDR images. Try to think of the areas that are going to be emphasised that may previously have been hidden or overlooked, such as the shadowy areas in architecture. Also, don’t be afraid to include more of a cloudy sky in landscape images, for example, as tone mapping will bring out the clouds to such an extent that they may subsequently become an unexpectedly pleasing focal point of the image.
Low and wide-angle shots can also benefit greatly from HDR processing. Much the same as with conventional shooting, always look for a perspective beyond the norm to transform your images.
Bracketing and Data Maximising
It is possible to create a type of HDR image from a single Raw file, but to achieve true HDR with minimal noise, it is best to shoot multiple exposures using the AEB or bracketing function built into most cameras, or to simply shoot a range of exposures manually in conjunction with a tripod. The reasoning behind the AEB function is to expose one image correctly and then over- and underexpose two more by a selected number of stops. In doing so, you record the maximum amount of dynamic data from your subject, and will in turn have more image data to play with at the processing stage. As shooting HDR is concerned with retaining and displaying as much image information as possible, it is a good idea to shoot the composite exposures in Raw before converting them to TIFFs.
Much the same as including several bracketed exposures, the uncompressed Raw file will contain more image information and will benefit your final image. While it may result in a slightly longer workflow due to demands upon the post-processing capabilities of your computer, the end results will be more than worthwhile. There is a lot of debate as to just how many exposures you need to combine in your finished image, with composites created as a result of anything from two to 16 exposures. However, the general consensus is that for areas of higher contrast you’ll need more exposures, while lower contrast requires fewer. Most cameras have the ability to capture at least three images in AEB mode, and for the majority of scenes that’ll be enough to capture the full dynamic range. It’s often an idea to experiment with the number of exposures, and the range of ±EV values, to see what suits.
How to Shoot an HDR Image
There are many ways to obtain good Raw material for HDR processing. Here are a few top tips…
STEP 1 – Minimising camera shake and movement is essential when looking to get a crystal-clear HDR image. Set up your camera on a sturdy tripod and shoot either bracketed images or manually, using a remote, cable release or the self-timer.
STEP 2 – Where camera settings are concerned, try to shoot in Raw at all times. This will allow you not only to perform any minor tweaks needed at a later date, but also to capture the maximum image data for your final image.
STEP 3 – To determine your exposure range, set the camera to auto and meter for both the lightest and the darkest areas of the proposed shot, then set the camera to the middle of the two and shoot the required images in either AEB or manually.
What is HDR?
Dynamic range is defined as the ratio between the brightest and the darkest areas of a scene. Therefore, when referring to a ‘high’ dynamic range, we are concerned with displaying a wider range of bright and dark areas than is possible in standard digital photography, or a limited dynamic range image.
The process of the High Dynamic Range imaging technique manages to overcome the restrictions of the limited dynamic range of conventional digital cameras by utilising both exposure blending and tone-mapping techniques in tandem, using either recent versions of Photoshop CS or specialist software packages.
The idea is to take several images of the same subject at different exposures, either utilising AEB (automatic exposure bracketing) or manually, and then merge them together. While the results can be striking, there are potential problems in production, so it can take a lot of practice to perfect. The number of exposures required can vary, so don’t be afraid to experiment when shooting.
When to Use HDR
The HDR technique can be applied to a whole host of settings and subjects. However, there are several genres to which the technique lends itself in particular…
Landscapes: One of the most popular subjects for the HDR post-processing treatment is the landscape. The ability to handle the dynamic data throughout a landscape shot is of huge benefit when shooting a scene where the sky and foreground necessitate different exposures. In this example, detail on the far mountains and highlights on the clouds would have been lost without accurate HDR processing. For the best results, try to get out there when the sun is setting or there’s a storm brewing!
Architecture: Managing to reveal both the fine highlights and what lurks in the crevices of buildings is a real benefit of the technique, as is the effect on subtle lighting. Next time you’re at church on a Sunday or pop out for a pint, consider taking your tripod and bracketing a few images.
Portrait/Still life: While portraiture and still life images may not be the most conventional of subjects for the HDR treatment, the effect can be remarkable. Subjects shot in difficult or moody lighting often create the best results.
Interiors: Achieving the correct exposure for both the interior and the exterior of a room is nigh on impossible without a sophisticated lighting set-up, yet is easily achieved with HDR. Try wandering around some historic buildings or maybe even just try the technique in your own front room!
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