HDR - Fantastic Tool or Photo Fantasy
Different Strokes for Different Blokes
Yikes! What do you think about this photo? I guess some of you will really like it, others will be revolted by it. And fair enough to. Welcome to the world of High Dynamic Range (HDR) photography.
Contrast Confounds and Confuses
One of the great problems photographers have to deal with is contrast. Back in the day you could describe the scene you're photographing, at least in part, by its contrast. The same was true for the film and paper used to record that scene and as one way to define the quality of a lens.
These days we can re-categorize contrast in relation to the capture device (digital camera or film/scanner); the subject or scene photographed, based upon the range of reflectance within that subject or scene; and the display or outcome (monitor or print). Other related terminology includes the following:
Scene Brightness Range
The difference between the very darkest and lightest areas of the scene can be referred to as the Scene Brightness Range.
Traditionally this term was used to describe the measurable differences between the lightest and darkest discernable densities in an image that fall just above jet black and below pure white. So, unlike the Scene Brightness Range, the darkest of these tones is not jet black, rather its a very dark area that holds the first hint of tonality (near black), but no detail. Likewise, towards the other end of the scale, the upper end of the Dynamic Range ends at the lightest tone (near white) just darker than pure white. Its the lightest highlight area, but without any texture, below pure white.
Defining a reduced range of tonality, compared to the Dynamic Range, and defining the difference, in stops, between delicate textured highlights and subtle detail in shadows. Either end of the Textural Range marks the boundaries around which we can discern a sense of substance.
In the case of a portrait of a bride and groom the term Textural Range could be used to describe the delicate work on the bodice of the bride's dress and, at the other end, the pleats in the groom's trousers and the folds in his suit. Retaining information in this areas adds a sense of 3-dimensional shape to the subjects in the photo.
Where the Eye and Medium Differ
One of the great problems associated with photography is the inherent inability of a film-based or digital camera to record the wide brightens range under which people are often photographing in a way that accurately matches our memory of that same scene.
Actually this is a difficult subject because the brain works at a variety of levels. For the sake of this article lets break that down into very simple, layman terms. The brain receives information from the eyes and assembles an image that makes sense to it. But in making that single image the brain is actually receiving several images sent from the eyes as they scan and focus on areas of the world around them.
Let's say you're ambling down the street on a bright sunny day. There are many things that combine to determine your memory of what is in front of you. Memory is, of course, a fickle thing and here are just a few of the things that could make your memory of that moment and what you saw very different to that of the person walking next to you.
- your state of mind: happy, sad, rushed
- relative comfort: hot, cold, sore feet, full or empty stomach
- who you're with and what you're thinking about
So much for an unbiased, unemotional and factual account of what you saw. Such things are impossible to achieve. All you can hope for, which is something artists understand and pay attention to, is how you felt about what you saw. Pablo Picasso' s Guernica, which portrays his response to the bombing of this small town in Basque Spain by Nazi Luftwaffe and the Italian Aviazione Legionaria, in support of General Franco during the Spanish Civil War, is just such an example.
OK, Back to Photography
As you're walking along your eyes will be drawn to bright, colorful parts of the scene around you. To record an image of a bright area the iris of your eye would likely close down, much the same as the aperture within a camera lens does, to be able to render as much subtle texture in those bright areas as possible. Likewise, when you look into the shadows the iris will open so as to discern detail within this much darker part of the scene. The image formed in your brain is, therefore, a combination of several snapshots sent to it from your eyes and formed into a single image by the brain.
High Dynamic Range (HDR) photography came about as a way to help photographers deal with the camera's inability to record the relatively large range of brightness levels (i.e., tones) between delicate highlight textures and subtle shadow details within a relatively high contrast situation.
Now the problem with HDR is neither the concept nor the technology. The first is totally reasonable and the second constantly improving. Rather its the application of this technology that is a worry to many old school photographers.
I guess it's both a blessing and a curse to enter the world of photography without having spent years working with film, particularly in a traditional darkroom environment. The blessing is that, ignorant to all the rules and constraints associated with a mature technology (it is, after all, around 180 years since the invention of film-based photography), the newbie is free to explore their creative nature relatively unhindered by old school doctrines.
The curse is that, without prior experience or tuition, that same person may lack the aesthetics (i.e., understanding of beauty) to be able to produce an acceptable result. And that's one of the reasons why so many HDR images look gaudy or just plain horrible. Try to spend time looking at a portfolio of such images and you'll come close to losing your lunch.
Now that's not to say that the newbie can't make innovative, evocative and even memorable images. But for those that do there will be so many that just produce something akin to plastic goo. And that's OK to. As long as they're having fun, and staying safe, who am I to criticize this stage of their creative journey. We've all been through it, or something akin to it. The fact is that many old timers would likely benefit from some of the creative spirit these new players bring to the art of photography. I would just urge all folks who explore the amazing world of HDR to do so in moderation. Your decision, which may well be image dependant, should always be outcome based. (Though, of course, the road by which you reach that outcome is a critical part of the creative process).
We can outline the basic process in producing a HDR image as follows:
- Fix your camera to a sturdy tripod
- Meter the scene
- Take a series of exposures (e.g., 3 or more) based on the dynamic range of the scene
Ideally the amount of exposures you'll make is dependent upon the actual dynamic range within the scene. The higher the dynamic range the more exposures you'll need to ensure the shadows are nice and open and the highlights aren't burnt out. The fact is most folks can't be bothered with all that and usually take 3 exposures, as follows:
-2 stops, Meter As Read (MAR) and +2 stops over what the camera's light meter recommends
Once you download your images onto your computer or external hard drive you can select the series in question (I do so from within Adobe Lightroom) and open them in Photoshop CC, which includes a few HDR plugins, or a dedicated HDR image processing application like Google/Nik software's HDR Effects Pro, Photomatix Pro or Aurora HDR.
A single composite image encompassing a far greater tonal scale than was the case with any of the individual files is what will result. While its possible to complete this process with JPEG files you'll likely produce better results when working with your original RAW files.
I think one of the problems with HDR is that the software, in the process of producing a single image with an extended dynamic range, tends to amplify color saturation and noise. For that reason I wouldn't normally recommend altering anything other than White Balance and, where required, Noise Reduction, in your RAW processor (e.g., Lightroom) prior to opening your images in the HDR application. Leave Sharpening and Clarity well alone.
The default composite image that's produced by the HDR application often provides a good starting point. And, while you can do better, further processing can lead you down a very slippery rabbit hole. There is a preview button but it doesn't take you back to your original file or the Lightroom processed image. It only takes you back as far as the default image produced by the HDR application, which I think is problematic as you're unlikely to see how much the image has been changed from its in-camera generated RAW state. That's because what you're looking at is not the original, but an already heavily processed file. When in doubt I pop over to Lightroom to remind myself of what the files looked like before the HDR treatment. I can then modify the image to produce a more realistic result.
In this post I've included images from 2011, when I was very new to HDR processing. And I think that shows. The night scene in Bruges is over the top and features a pretty weird looking moon. The above photo of Schoenbrunn Palace in Vienna features, to my mind, an overly aggressive sky. What's more magnifying the image will show the problem I was having, back then, with placing individual images within a HDR workflow in register when combining them into a single, composite image. It's a really poor result. It's okay on the desktop, but would not stand up to printing for display on a wall. (I must re-visit and re-work this image down the road aways).
We all get better with practice and camera's become better featured in relation to the workflows required for processes such as HDR photography. These days my images are recorded on a Sony a7R II camera which allows me to record up to 9 frames, at one-stop increments, within a single sequence of bracket exposures. I do most of my HDR work in Photoshop CC via the Merge to HDR Pro process.
Glenn Guy's Current HDR Workflow
The secret is to select 32Bit once you're inside that plugin within Photoshop. The resulting image will look terrible, but that's only because our monitors can't display in 32Bit. What's important is that you have far more detail to work with than would be the case with a 16Bit image. All I do is save the file and send it back to Lightroom for basic processing after which it comes back into Photoshop when most of my post processing workflow is undertaken.
The Tool vs. the Tool
Your mission, Jim and Jane, should you choose to accept it, is to use this wonderful new technology to help overcome the fundamental inability of your camera to record the full range of tones you see in the world around you or to employ the software to produce a look or treatment in line with your own creative intentions.
If you hate the whole idea of HDR photography it just might be because you haven't used it. We human beings are funny old folk. We're often scare of the new and, as a result, shun it. Being a late adopter is one thing, but failing to improve the quality and communicative power of your images due to fear of new technologies is akin to a sin for many creative artists.
Please don't judge HDR photography until you've tried it for yourself. But I warn you its addictive. Just don't loose sight of what your original image looked like and what your outcome should be. By all means allow the process to suggest alternative outcomes, but make sure you stay in control of that outcome. Embrace change and experiment. Just remember that technology is a tool in the hands of creative souls. It is neither a religion nor an outcome in itself.