Get Great Photos in Low Light
Light is photography's essential ingredient. Abundant illumination makes our job easy--we simply compose and shoot. But what happens when the lights go down? Do we become slaves to unflattering bursts of an electronic flash? Not at all. By mastering a few basic techniques, you can turn off the flash to capture beautiful, evocative images. Look in your camera's settings for the lightning bolt icon, and select the flash off option.
Know Your ISO
Now that you're going flashless, you must find a way to compensate for the lack of supplemental light. One way to do this when shooting with a handheld camera, is increase the sensitivity of your camera's image sensor. You control sensor sensitivity with the ISO setting. Choose ISO 400 to 800 for compact cameras, or ISO 400 to 1600 for DSLRs. Why do the two types of cameras have different ranges? The internal electronics in DSLRs are better-suited for working in low light than are the electronics in compacts. A low light exposure at ISO 800 on a compact will show more image noise than on a DSLR. (To most folks, image noise looks like film grain. Instead of smooth tones, you can see a bit of digital texture.) If your tolerance for image noise is low, this is a compelling reason to upgrade to a DSLR.
If your camera has an auto-ISO setting, you could use that instead of constantly making the adjustment yourself--but should you? The answer is a definite "maybe." Refer to your owner's manual to see what the range is for auto-ISO. If, for example, the auto-ISO range on your compact camera is 100-400, or even 100-800, you should consider using this setting. No matter which number the camera chooses in that range, you will probably be happy with the picture. On the other hand, if the auto-ISO range on your compact is 100-3200, don't use it. The images captured at 1600 and 3200 will not be attractive, and you will surely be disappointed.
Avoid Camera Shake
With either type of camera, the amount of time the shutter stays open during the exposure increases as the light gets dimmer, even after you increase the ISO. The longer exposure lets more light reach the sensor, thus increasing the odds for a nicely exposed picture. Sounds great, right? Well, yes, except that longer exposures on handheld cameras increase the risk of camera shake. At mild levels this effect appears as an overall softness of the image; at the high end, your photos will be downright blurry.
Most photographers combat the ill effects of camera shake in one of three ways. The first two are used in combination with increasing the ISO as mentioned earlier. The third, using a tripod, doesn't require ISO adjustment. Here's what you can do:
Change Your Lens If you're using an SLR, try attaching a fast lens that lets more light pass through to the image sensor. Every lens has a large maximum aperture opening, measured in f/stops. A zoom lens that comes as part of a camera kit may have a maximum aperture of f/3.5. But a single focal length 50 mm lens usually has a maximum aperture of f/1.8 or more. The lower the f/stop number, the more light can pass through the lens and the less time the shutter has to remain open. Many photographers who shoot with existing light use a fast lens in combination with image stabilization and a higher ISO to get crisp exposures without having to carry around a tripod.
This existing light portrait was captured with a Canon G9 at ISO 400 without a tripod. Even though the shutter speed was 1/20 second, the image has good sharpness, thanks to image stabilization.
Turn on Image Stabilization Image stabilization (IS), which allows the camera to electronically offset unsteadiness during exposure, is a wonderful technology that often can compensate as many as three shutter speed settings. What does that mean? Shutter speed settings correspond to fractions of a second and are listed in this sequence: 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000 and upward. Most steady hands can avoid camera shake at 1/30 or upward without engaging IS, as long as you're not using a telephoto lens (which increases magnification and changes the whole equation). If you're in dim lighting and the camera determines that you need an exposure of 1/8 of a second to make a good picture, you're going to get camera shake. But if you have IS turned on, the camera can compensate for shakiness so even though you're actually shooting at 1/8, your electronic helper gives you the effect of shooting at 1/60 of a second. This is a huge help in existing-light photography.
Keep in mind though that when you're photographing people in low-light conditions, you have to deal with human motion as well as camera shake. (Image stabilizers only steady the camera--they can't stop people from moving.) In those situations it's best to increase the ISO and use as fast a lens as possible to keep your shutter speeds as high as possible. This technique freezes subject movement. (For an explanation of different types of image stabilization, see "Steady Your Shot.")
Use a Tripod If your camera doesn't have IS, then mount it on a tripod. With a tripod you can shoot at any shutter speed you want. It is so effective at steadying the camera that you can even lower the ISO down to 100, which will curtail image noise and let the camera make a very long exposure, such as a minute (which is an eternity in photography terms). Just remember not to jar the camera when pressing the shutter button. The easiest way to avoid jostling the camera is to use the self-timer. You press the button, the camera settles down while the self-timer counts down 10 seconds, then it's rock steady when the shutter opens. A tripod is especially helpful when shooting buildings and landscapes in low light, since you don't have to worry about subject movement (unless there's an earthquake of course).
Coping with Color Balance
Once you stray from regular daylight and wander into the exotic world of artificial illumination, you'll notice that your pictures display a variety of unusual color casts. Interiors illuminated by fluorescent lighting have a ghoulish greenish tint, while tungsten-lit scenes seem overly reddish. Photograph Aunt Jane next to a window in the living room and you may notice she looks a little bluish.
These lighting conditions are extreme enough that they often exceed your camera's ability to correct them using its auto white balance feature. Just as you've taken control of the lighting by turning off the flash, you can wean yourself off automatic color correction, too. Go to your White Balance menu and take a quick inventory of the icons there. You should see a sun, cloud, traditional light bulb, fluorescent tube, and a few more icons. These white balance presets tell your camera about the lighting you're working in to give you the best color possible.
If you have the time to experiment a bit, you might want to read up on your camera's Custom White Balance setting. It allows you to take a color reading off a white sheet of paper; the camera attempts to adjust the color temperature for that specific lighting as measured from the white paper. I've had very good results with this technique. (For more advice, see my previous article on eliminating color casts.)
If you forget to set your white balance before you shoot or can't correct the bad color, consider converting your image to black-and-white in software after the shoot, thereby skirting the low-light color issue all together. Existing-light pictures in grayscale usually look terrific, and many people will appreciate your artistic eye. You can use the B&W preset in the Effects palette in iPhoto, or the Monochrome brick in Aperture. Other image applications such as Adobe Lightroom and Adobe Photoshop also have tools for converting images to grayscale.
Go Forth Into the Night
You no longer need your flash as protection against fading light. Although these techniques are the basic foundation of existing-light photography, you'll be pleasantly surprised at how far you can travel with them.
Derrick Story is the author of The Digital Photography Companion (O'Reilly Media, 2008) and hosts a weekly podcast at www.thedigitalstory.com.