Читать книгу Digital Photography For Dummies - King Julie Adair, Julie Adair King - Страница 34

One cause of blurry pictures is camera shake. If the camera moves when the shutter is open, the entire image may be blurry even when focus is perfectly set. The longer the exposure time, the longer you have to hold the camera still to avoid this type of blur. Shooting with a telephoto lens makes things even more difficult, especially if that lens is long and heavy.

You can avoid camera shake by mounting the camera on a tripod. But a feature called image stabilization can enable you to get sharper shots when you handhold the camera. The feature may go by different names depending on the manufacturer: vibration reduction, antishake, vibration compensation, and the like. Whatever the name, the feature is implemented in one of two ways:

 Hardware-based stabilization: With this method, sometimes called optical image stabilization, the antishake benefit is produced by a mechanism built into the camera or the lens. This type of image stabilization is best.

 Software-based stabilization: This type of stabilization — sometimes known as electronic image stabilization, or EIS — is applied by the camera’s operating software rather than a hardware mechanism. It works differently depending on the camera.In some cases, the camera applies some complex correction filters to the image when motion is detected. Other cameras address camera shake by automatically increasing the ISO setting, which makes the camera more sensitive to light. When the camera is at a higher ISO, you can use a faster shutter speed, which means that the length of time you need to hold the camera still is reduced. Unfortunately, a higher ISO often brings the unwanted side effect of image noise, as discussed in the earlier section “High ISO performance (low-light picture quality).”

Even the best possible stabilization system can’t work miracles; you still need a tripod for very long exposures. But you can expect to get a steady shot at shutter speeds slower than what you can enjoy without stabilization. How much slower depends on the capabilities of the camera or lens as well as your ability to hold the camera still.

Long story short (too late, you say?): This is one camera feature that I highly recommend to photographers of any level.