Different specs are important to different people, but a few generalizations hold true for most cameras.
If you intend to take pictures only to e-mail them to distant friends, upload them to sharing sites, or print them at snapshot size, a camera of most any resolution will do. Even so, having more pixels gives you greater flexibility—you can print sharper pictures at larger sizes or crop and print small sections of pictures.
These days, it's hard to find a camera with a resolution of less than 10 megapixels, which is overkill for most shooters. As a rule of thumb, 5 megapixels is enough to make a sharp 8-by-10-inch print; and 8 megapixels is enough to make a sharp 11-by-14-inch print. A 10-megapixel camera can produce acceptable prints of up to 13 by 19 inches, though they may lose some detail. Images from a 13-megapixel camera look good at 13 by 19 inches and can be pushed to 16 by 24 inches. Many digital single-lens reflex (DSLR) cameras today offer 16-megapixel sensors—all the better if you want to creatively crop your images.
If you only share your shots digitally, couldn't care less about cropping and resizing your shots, and/or want to save a lot of space on your storage card, we recommend lowering the default resolution of your camera's photos to either 5 megapixels or 8 megapixels. Most cameras let you change the capture resolution to a lower setting, but check to see whether the model you have in mind allows you to do it.
Cameras with larger sensors and lenses normally take better shots, regardless of the unit's megapixel count. Bigger sensors normally create better images, especially in low light, as do higher-quality lenses; this is why DSLRs take such stunning photos. In general, you pay more for a larger sensor.
If you can't get any hands-on time with a camera before deciding whether to buy it, check the specs to see how big its sensor is. It's not the only piece of hardware that factors into a camera's overall image quality, but it's usually a great indicator of how good your photos will look.
Shutter lag and startup time
Even if the camera you've decided to buy has some drool-inducing specs, shutter lag may prevent you from capturing the perfect shot. When it comes to shutter lag, a camera can let you down in a handful of ways: a slow shot-to-shot time, a slow startup-to-first-shot time, and a laggy autofocus that has trouble locking in on a crisp shot.
You can check for only one of these problems by scanning a camera's spec sheet: To get a sense of a camera's shot-to-shot time, look for the camera's "burst mode" or "continuous shooting" count in shots per second. This is the number of shots a camera will take in rapid-fire succession as you hold the shutter button down. If you're interested in shooting a lot of sports or action photography, look for a camera with a continuous shooting mode of at least 3 shots per second
Bear in mind that a camera's listed continuous-shooting speed usually refers to situations where the flash is turned off and the focus and exposure are locked during the first image of the batch. Some higher-priced cameras have continuous autofocus enabled from shot to shot. Other cameras have very high continuous shot rates, but usually they significantly reduce the resolution of each photo in order to speed up image processing and write speeds.
The other forms of shutter lag are important reasons for you to get some hands-on time, if possible, with any camera before you buy it. Check to see how long the camera takes to power on and snap a first shot; generally, anything close to a second is considered fast. Another good hands-on, in-store test is to see how long the camera's autofocus system takes to lock in on a shot after you press the shutter button halfway down. If the camera searches in and out for more than a second, you'll be better off with another camera for sports or spur-of-the-moment casual shots.
Size, weight, and design
To some users, a camera's weight and its ability to fit in a pocket may be more important factors than its resolution. Slim cameras are convenient, but they frequently have tiny dials and few buttons, and these characteristics make changing settings somewhat trying. Smaller cameras usually don't have manual controls, instead relying on automated in-camera settings that pick the right in-camera settings for your shot. These auto modes normally do a great job, but you have less control over the look and feel of a photo.
Zoom lens and image stabilization
Inexpensive cameras often lack a powerful optical zoom lens, but that's changing. Among the new breed of $200-range cameras are a few pocket megazooms: compact cameras with optical zoom lenses as powerful as 10X optical zoom.
If we had to choose between a point-and-shoot camera with stronger optical zoom and one with higher resolution, we'd take the model with the more powerful zoom lens—it means that you won't have to magnify your subject and then use software to crop the image (and discard some of the resolution as a result).
If you're buying a DSLR or a compact interchangeable-lens camera, both the zoom range and the stabilization features depend on the lens you're buying. A few DSLRs and interchangeable-lens compacts have in-body image stabilization, meaning that your images will be stabilized by in-camera mechanics (usually, the sensor physically moves to compensate for shake) regardless of which lens you attach. If your camera doesn't have in-camera stabilization features, you can obtain optically stabilized lenses, but they're a bit more expensive.
Fixed-lens cameras now offer zoom ratings beyond 40X. These lenses are great for nature or sports photography, but unless the camera has good image stabilization (look for a camera with optical image stabilization) or a very fast shutter, you may need a steady hand or a tripod to avoid blurry pictures at extreme telephoto lengths. Before you buy, you should try a camera's autofocus at full zoom: We've tested some models that were slow to focus at full zoom.
Also note that not all high-zoom cameras are created equal. You know how you have to ask everyone in your group shot to gather in close to get in the shot? A wide-angle lens can solve that problem, so pay attention to the wide-angle end (lowest number) of the optical zoom range, as well as to the telephoto end (highest number). If you take a lot of group shots or landscape shots, the wide-angle end of the lens is even more important; it lets you capture more of the scene when you're zoomed all the way out. A good wide-angle lens starts at about 28mm or less on the wide-angle end; the lower the number, the wider-angle the lens.
Be wary of advertised zoom ratings—many vendors quote "extended zoom" or "simulated zoom" counts. These combine the optical zoom (which moves the lens to magnify the subject) with digital zoom, which merely magnifies your image digitally by cropping and zooming it. Optical zoom gives you all the benefit of the camera's maximum resolution, combined with the ability to focus in tight on faraway action.
All digital cameras take .JPEG images by default, which compresses your photos and compromises the details in each shot. Many DSLRs, mirrorless interchangeable-lens cameras, and premium compact cameras allow you to shoot in RAW mode.
Shooting in RAW preserves all of the data in your images without compression, letting you bring out more detail in your image during the editing process. However, it also means that the file sizes on your images will be much higher. If you plan to shoot in RAW mode, make sure that you have a high-capacity storage card to hold all of the extra data. You may also need special software for each camera in order to view RAW images.
For close-ups and other situations where a camera's autofocus doesn't quite cut it, switching to manual focusing can help you get the shot. Low-end cameras often omit manual focusing, which forces you to trust the camera's autofocus system and lose a bit of control over the look of your shot. It's a good idea to test a camera's autofocus before you buy; some cameras struggle to lock in on a focus point at full telephoto or in macro mode, meaning that you may not be able to capture your perfect shot.
If you have an existing storage card that you'd like to use with your new camera, make sure that it's compatible with your new purchase. Most cameras on the market today use SD (Secure Digital) or SDHC (Secure Digital High Capacity).
SDHC (Secure Digital High Capacity) cards are more expensive, offering storage capacities up to 32GB, but they're not backward-compatible with standard SD slots. There's also a more recent, higher-capacity format on the block: SDXC, which supports storage capacities up to a whopping 2TB; those are even more expensive, and they aren't compatible with all SD/SDHC card slots.
In addition to storage capacity, there's also the speed issue to consider. SD and SDHC cards come with a "Decoding Class" rating, which refers to the data-writing rate for each card. The higher the Class number, the faster the card's write speed; if you're planning on shooting video or using a high-speed burst mode, look for a Class 4 or Class 6 card at the very least.
To complicate matters further, some smaller cameras support MicroSD or MicroSDHC cards, a smaller version of the SD card format that isn't compatible with full-size SD slots. Older Sony cameras take MemoryStick cards, and older Olympus cameras use the XD card format; both companies' new cameras now support SD/SDHC cards. What's more, many higher-end DSLRs have a larger-format CompactFlash card slot.
Cameras may use one or more of several types of batteries: Typically, brand-new cameras use proprietary rechargeable batteries that can cost from $25 to $65 to replace. Lower-priced and older cameras use standard AAs—either nonrechargeable alkaline ($5 for four) or rechargeable nickel metal hydride (NiMH, about $14 for four)—or high-capacity disposable CRV3s (around $10 apiece; some cameras take two).
With their big LCD screens and whiz-bang features such as Wi-Fi and GPS, some digital cameras quickly drain batteries. That limits the time you can use the camera while you're out and about. Battery life and camera cost often aren't related: Some inexpensive cameras have great battery life, and some expensive ones use up a charge quickly. Either way, it's a good idea to buy spare batteries.
Movies and sound
The majority of today's cameras can capture 1080p high-definition video. Most of them record this full-HD video at 24 fps or 30 fps, and a few of them capture 1080p video at a brisk 60 fps, which usually translates to smoother-looking video. If you plan on shooting a lot of video with your camera, here are some things to consider:
• Can you use manual exposure controls while shooting video?
• Can the camera zoom in and out optically while filming video?
• Can you use manual focus and continuous autofocus while shooting video?
• Does your video-editing software support the format your camera records in? Most cameras' video output will work with any video-editing program, but the AVCHD format can be tricky to work with. That said, AVCHD files will upload directly to YouTube.
• Do you have a Class 4 or Class 6 SDHC card? You'll want to pick one up to make sure that your card can handle the speed of video capture.
All digital cameras let you shoot in Auto mode—just press the shutter release, and you get a picture. Some cameras also offer aperture- and shutter-priority modes, in which you adjust the size of the lens opening or how long the shutter stays open, and the camera automatically controls the other variable to give you the proper exposure.
Typically, you'll use aperture priority to maintain control over an image's depth of field—for example, to blur the background of a shot while keeping the foreground sharp—and shutter-priority mode to capture fast-moving subjects or low-light shots while using a tripod. A camera that relies exclusively on full auto will attempt to keep both the foreground and the background in focus in the former example, and it will probably blur the moving subject or boost the ISO to noise-inducing levels in the latter.
Cameras that offer priority modes also provide full-manual exposure control, in which you set both variables. These modes make a camera adaptable to almost any situation.
The sleekness of a camera is usually inversely proportional to how easily you can adjust its settings. DSLRs, interchangeable-lens cameras, and premium compact cameras are studded with buttons and knobs; and if you know what you're doing, they make adjusting the camera's settings a quick-and-easy affair.
When evaluating a camera, consider how easily you can reach common settings—exposure controls, ISO adjustments, continuous-shooting options, and manual focus controls—and how easily you can play back just-taken images. Too many buttons, and you waste time trying to figure out which button does what; too many menus, and you waste time digging through them.