ESFotoClix Blog

Yell, “HDR!” in a crowded theater, and someone will turn you in to Homeland Security. Such are the negative connotations and powerful emotions High Dynamic Range (HDR) elicits. Why such opposition to what should be another useful technique to expand the quality of your photographs? “Over-cooked, impressionistic cartoonish clap-trap images,” will be the raw answer you might get from certain folks. The feeling even among those who would hold a softer stance is that HDR abuses everything we know and understand about a photograph. In some ways, this may relate to some of the discussions we have had regarding realism and its relationship to photography.

Before we address whether HDR is a valid photographic technique, let us establish what it is and what it does. Simply put HDR seeks to increase the dynamic range (DR) of today’s digital cameras through the combination of under-exposed, over-exposed and just-right-exposed captures. To throw some numbers around, today’s DSLRs feature a DR somewhere between 7-9 stops, depending on who you ask and how the camera is being tested. As an example, a 3 frame HDR capture that deviates by 1 stop from the center exposure increases the dynamic range of your image by 2 full stops, so your 7-9 just became 9-11 stops. And if you took 5 frames, also separated by 1 stop each, now you have an increase of 4 stops, and you have achieved a 11-13 stop DR.

Now contrast this with film, and let’s go all out with Tri-X B&W film, which is reported to provide 18(!) stops of dynamic range, while regular B&W film features around 14 stops. You can see that with the 5 frame HDR example you’re in the ball-park for regular B&W film. Some observations come to mind.

First, if you hate HDR, realize that Ansel Adams with his black negatives was doing HDR before many of us were born. Second, if you realize that a 16-bit image doubles the number 2 16 times, 16 stops is a good approximation(1) of the range it can contain. If you want to do a 9 frame HDR capture, either reduce the frame-to-frame stop separation (say, to 1/2 stop) or you will need to generate a 32-bit image. The third observation is that the best print paper provides 6 stops in image reproduction capability, and if you’re displaying it as a JPEG or PNG file for Web consumption, you’re back down to an 8-bit image. Take that into account before you spend a lot of time producing images with extreme dynamic range. Yes, having more range gives you more latitude to process the image … until you have to make your final image.

All that to say, “easy does it,” and “everything in moderation.” If you want to get artistic and do some impressionism or reality-bending stuff, go for it. But if you want to capture a photograph, take care of your image by processing it in such a way as to produce results one would expect from a photograph, as opposed to what a button-press-and-go software package would give you.

Pop quiz: which of these is the HDR image?

Answer: who cares? All three aim at being photographs, and shouldn’t be judged on whether they were processed with HDR or some other method. If you must know, all 3 are HDR images.

Footnotes:
(1) Theoretically, a 16-bit per channel image can contain a much larger number of stops (up to 2 raised to the 16th power). The question hinges more on what is practical in terms of what can be perceived by the human eye and what can be represented without loss of fidelity in the image’s display medium.

References:
http://www.luminous-landscape.com/tutorials/hdr.shtml
http://www.northlight-images.co.uk/article_pages/16_bit_black_and_white.html

Lately I’ve been re-evaluating the types of photographs I go after, and even why I take them in the first place. At times it seems I am seeking, making and even concocting photo opportunities so I can collect trophies, be it in the form of countless files to fill my whirring hard disk, or a print or two I can hang on a wall. After spending some time polishing these trophies, I display them prominently, either at my gallery or some other photo stream. See how good I did?

Along the way, I have discovered that images captured with this mindset are interesting one moment and so-so the next. I connect with them initially, or convince myself that they appeal to me, only to find I grow tired of them and that no one else really much cares for them. These trophies, these badges of honor I collect, lose their value quickly and at best gather dust, while most simply fulfill the role of maintaining electrons states in my various storage devices.

Here are two images I captured while purposefully seeking to capture beach action shots. The first is as I expected and envisioned; the second appeared out of the corner of my eye, and I was mindful enough to drop the action and reframe. One is a trophy – complete with diagonal composition and simplification — while the other one is not. I’ll let you decide which is which.

This brings up a tension between being purposeful and prepared in the types of images we capture vs. relaxing, just waiting for the next awe-inspiring shot to materialize on its own. Clearly purpose and preparation play a key role. A good photograph won’t drop into my lap while I shop online for my next cool lens. Yes, getting out there with the right equipment and knowing how to use all the gadgetry in my camera bag is important. However, going out to concoct the next trophy for the photographic wall of fame seems misguided – and not much fun.

In the end, a balanced approach comes from the realization that great images are gifts more than they are acts of the will. Yes, we have to be ready – skilled and equipped – to receive them, but it is seldom true that we can force a great photograph into existence. We can recognize the right lighting for a gorgeous sunset, but we can’t manufacture the right mixture of clouds nor the angle of the sun. We can react quickly to capture a key moment during a sporting event, but we can’t make the athlete perform at the level a decisive play requires.

Above all, while trophies crowd our real and virtual walls, a great image packs and unveils emotional content. Such an image transcends trophy status by capturing a special, perhaps unique moment in time that evokes emotional impact both for the photographer and the photograph’s viewer.

Along the road to capture good photos, I often found myself cropping them in post-processing, usually feeling I had failed in preserving the original image or succeeded in degrading image quality through the resulting reduction in resolution. In some cases, cropping was acceptable and even necessary, as when the final image demanded frame dimensions other than the 4:3 or 3:2 aspect ratios that come with most digital cameras. More often than not, however, I found myself cropping to remove unwanted distractions, or to more tightly focus attention on the subject, or, if I must admit, to achieve the much-prized rule of thirds.

The feelings of cropping guilt nagged me for years until recently, when I realized that cropping could teach me how to make better framing choices. In quiet reflection in front of my computer monitor I began asking, “if I were taking this shot right now, how would I frame it differently, and why?” Then, I would crop the image as I would want it captured and tell myself, “next time, that’s how you want to frame it with the camera.” This was a process of reprogramming the way I took images. It’s not as easy to reflect in the heat of photographic battle as it is in the quiet post-mortem of post-processing. After repeating this exercise for a few months, however, framing the way I would crop became second nature, and the guilt started to vanish.

Here’s an image from the Paris subway, as originally shot. I don’t go to Paris often, so after I returned home I was somewhat discouraged when I realized this image needed quite a bit of trimming around the top and right. Though not an award winner by any means, the cropped version becomes stronger by avoiding the centered track (bullseye!), along with the do-nothing space up top, and by creating more of a juxtaposition between the staircase and the track. The elimination of the right platform also simplifies the image and focuses the attention more strongly on the commuters on the left and the leading line that the staircase they are taking forms.

The trick is thinking about all the stuff that makes the second, cropped image stronger at the time of framing, then stepping to the left and zooming in to compose it right from the start. Then I would have a stronger composition without the loss in resolution that cropping causes.

Key Tip:
As you use cropping to learn how to frame better, you might realize that you often include more than you want to in your image because of the way you look through your viewfinder. It’s perfectly natural to focus your attention toward the center of the frame, or to be most concerned with your subject. It’s far easier to trace along the frame’s perimeter when sitting in front of a computer monitor, but you can teach yourself to let your eye wander along the edges of the frame while looking through the viewfinder. Doing so will reveal all those unwanted objects, or even whether you have the right amount of spacing between what you want to include in your photo and the edges of the frame.