Stunning Photos With High Dynamic Range, Part 1
Throughout much of history, artists have been concerned with approximating reality. For centuries, landscape and portrait painters strove to progressively improve their technique to better replicate the world around them. When photography arrived on the scene in the 1800s, some people thought painting would become a dead art form because cameras could so perfectly reproduce reality.
Nothing could be further from the truth, because cameras merely approximate the scenes they photograph. They are limited in myriad ways, not the least of which is their inability to capture the full range of light and color in any given situation. You've probably seen this yourself when you try to photograph a scene with a lot of contrast, such as bright sunlight and shadow or the setting sun counterpoised with city lights.
If you measure a camera's exposure latitude in terms of f-stops then you can say that digital cameras have a total latitude of about six stops. (Each f-stop setting on your camera double or halves the amount of light reaching the sensor compared to the subsequent f-stop.) The problem is that real-life situations tend to have many, many more f-stops of exposure information embedded in them. The typical solution is to pick the part of the picture you're most interested in (such as the shadows under the trees or the sun-baked green field near the horizon) and set the camera accordingly.
The HDR Alternative
But you've got a better option these days: High Dynamic Range photography gives you pictures with a much deeper exposure latitude. With HDR, photos can accurately depict the full range of colors, brightness, and contrast in a scene. You can get a dozen stops of exposure information rather than just six.
HDR relies on a technique in which you take a series of photos, each with a different exposure, and combine them afterwards on the PC. Intrigued? Check out some photos taken by HDR enthusiasts.
Taking Your Own HDR Photos
So how do you get started with HDR? Since HDR requires a series of photos, I highly recommend using a tripod. Yes, it's possible to hold your camera by hand, but the results may not be as good. You'll also need to rely on your image editing software to line up each photo perfectly--something I've never known to happen quite to my satisfaction.
Begin by setting your camera on the tripod and lining up your scene in the viewfinder. You'll want to minimize the camera shake at the moment of exposure, so I recommend using a remote control or the camera's self-timer.
I also recommend using the manual focus mode if your camera has one. Since you're going to take anywhere between three and nine exposures of the same scene, you need the focus to be identical in each shot. Here's what I do: I press half-way down on the camera's shutter release, which allows the camera's automatic focus mode to lock in. Then I change the camera from auto-focus to manual focus, locking in that focus for all my subsequent photos. If you can't do this with camera, you'll need to be extra careful about making sure the focus doesn't change between shots.
Finally, you need to control the exposure so that each shot has a slightly different setting. The easiest way to do this is to use your camera's bracket exposure control. Bracketing tells the camera to take a series of photos with a range of exposure--such as one stop underexposed, the correct exposure, and one stop overexposed. My camera lets me adjust the amount of exposure change (such as a half-stop or a full stop between shots) and the number of exposures in the series (three, five, seven, and even nine). If your camera has a bracket mode, this is definitely the way to go: Just set it up, hold down the shutter release, and the camera will run through the entire series, one shot after the next, stopping when it's done.
If your camera doesn't have a bracket mode, then you'll have to get a little more creative. You can bracket the photo yourself by taking the first picture at normal exposure, then using the exposure compensation dial (usually marked with a +/- symbol) to underexpose and overexpose subsequent images. Take a series of shots with the exposure control set to -1, -2, -3, +1, +2, and +3, for example. Throughout the process, remember to not move the camera or each shot won't be aligned properly.
Next week: taking these individual photos and turning them into a single, stunning, HDR photo.
Hot Pic of the Week
Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique. Every month, the best of the weekly winners gets a prize valued at between $15 and $50.
Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.
This Week's Hot Pic: "Bubble in Glass," by Bruce Farris, Moncton, New Brunswick
Bruce says: "I call this photo 'Bubble in Glass.' It's a macro image of a bubble that I discovered in a clear glass mug, which I took with my Canon PowerShot S400 Digital Elph. I think that it looks like a captured water droplet and I've actually fooled some of my friends into thinking it was. To take this photo, I set the camera to macro mode and turned off the flash. I shot it on the kitchen counter with light coming in from the window."
See all the Hot Pic of the Week photos online.