Even if the camera you've decided to buy has some drool-inducing specs, shutter lag may keep 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 grasp on 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; keep in mind that the continuous shooting speeds usually refer to situations with the flash turned off, as the time needed to recharge the flash will usually be longer than the shot-to-shot time. Some cameras are built for high-speed shooting with shot rates much higher than that, 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 to get some hands-on time with any camera before you buy it, if possible. 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. If the camera searches in and out for more than a second, you'd be better off with another camera for sports or spur-of-the-moment casual shots.

To some users, may be more important factors than resolution. Slim cameras are convenient, but they frequently have tiny dials and few buttons, which make changing settings somewhat trying. Smaller cameras usually don't have many manual controls, 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.