Photography and Dynamic Range

dynamic range is basically the difference between the brightest and the darkest areas in a scene. The greater the difference, the greater the dynamic range the scene is said to have. A scene with high dynamic range is also called a scene with high contrast.

Truth of the matter is that film and digital cameras have their limitations when capturing scenes with high dynamic range or high contrast. The challenge lies in their ability to record the brightest details and the darkest details of the scene at the same time, without any detail clipping. This becomes particularly difficult with high contrasting scenes, such as really bright skies against deep shadows. Of course, film cameras record a much higher dynamic range than do digital sensors. But still, both are not sufficient, for nothing is more adaptive and flexible than the human visual system.

The good news is, in this era of digital revolution, almost everything is possible. That said, there are mainly two ways to overcome the limitation of our digital cameras in capturing full dynamic ranges of scenes. First suggestion would be to make 2 exposures of the exact same scene. Once, you expose for the highlights of your scene (you take the light metering reading off the brightest area of the scene). And the second is to make an exposure of the exact same scene, this time exposing for the shadows (taking the light metering reading off the darkest area of that same scene). You then end up with 2 photos of the exact same scene. One recording all highlight details, and the other recording all shadow details. You then can merge these two photos using a photo editing software of your choice, such as Adobe Photoshop or Photoshop Elements, selectively hiding under- and over-exposed areas of each image and showing the correctly exposed areas of both. This way you end up with one correctly-exposed image showing the full dynamic range of your scene.

This method works great for still-life photography, landscapes, and other imagery involving non-moving subjects. And you need to use a tripod to make sure the camera doesn’t move while trying to record two exposures of one scene. There’s a drawback to this method though, and that is taking 2 photos of an exact exposed scene can be difficult at times where your scene is at constant change, such as photographing wildlife, people, landscapes with fast moving clouds, and so on. Not to worry though, cause here comes the second method that you can use alternatively to record your own full dynamic range masterpiece.

The second method is easy and much more flexible to deal with in the case of shooting non-still imagery, or when you don’t have a tripod to hold still your camera and prevent movement. It goes as follows: you need to shoot in RAW. Just one image per scene this time, and then you download your RAW photos onto a RAW converter software of your choice. I personally use Adobe Photoshop’s Camera Raw. It’s a brilliant, easy to use, and easy to understand software. And you can master it in no time. It installs automatically once you install Adobe Photoshop or Photoshop elements.

So what you do is open your raw images in camera raw, and make two conversions of the same shot. Once tuning your photo exposure settings to appropriately bring out all highlight details (bright areas details). And the other, tuning your photo exposure settings to appropriately bring out all shadow details (dark areas details). And then you merge the two converted photos using your photo-editing software. Just like before, you selectively hide under- and over-exposed areas of each image and show the correctly exposed areas of both. And once again you end up with a full dynamic range shot of your scene.

Graduated neutral density filters can also be used to increase the dynamic range of a scene that can be captured on photographic film or digital sensor. The graduated neutral density filter is basically split in two halves. The top half is dark, and works to hold back light coming from extra bright areas of the scene. And the bottom half is clear, allowing more light to register from dark areas of the scene. The filter is positioned in front of the lens at the time the exposure is made, with the dark half placed over a scene’s high-intensity region, such as the sky. The result is more even exposure in the focal plane, with increased detail in the shadows and low-light areas.

Though this doesn’t increase the fixed dynamic range available at the film or sensor, it stretches usable dynamic range in practice.

It is also worth mentioning that you can take advantage of high dynamic range scenes to record excellent stark, dark silhouettes. You should also know that your digital images may be in fact holding more dynamic range than you can actually see. Having a high quality monitor that is correctly profiled and calibrated is essential in your image editing workflow, and is something everyone should be aware of, and well informed about. After all, it is the tool you make your color and luminosity adjustments decisions with, so it is very important to be able to trust what you see on your screen display to be able to make those decisions. If you wanna learn more about monitor calibration and profiling, you can refer to this post I wrote for GOMEDIAZINE a while ago “>Color Management: Calibration and Profiling.

Below are a few excellent examples of high dynamic range photos. As you can notice, the level of color and luminosity details in both the light and shadow areas is extremely high…

Photo by Stuck in Customs

Photo by Aypho

Photo by lassi.kurkijarvi

Photo by .: sandman

Photo by wili_hybrid

Photo by wili_hybrid

Photo by Lone Primate

Photo by .: sandman

Photo by marcp_dmoz

If you have some pretty good photos with high dynamic range we would love to see them as well. Please link to them in the comments below so we can check them out…