While traditional film cameras typically require you to move the lens -- or your whole camera -- closer to an object to zoom in on it -- in a process called optical zoom -- digital cameras offer you the option to zoom digitally. Many digital cameras come equipped with both digital and optical zoom, each of which present its own advantages and disadvantages.
How Optical Zoom Works
As its name suggests, optical zoom entails moving your camera lens closer to the object you're photographing, with millimeter differences in actual closeness corresponding to more dramatic perceived closeness. How you optically zoom depends on the type of digital camera you have. If you use a compact point-and-shoot camera, you control optical zoom using a button or lever attached to the body of the camera. If you use a digital single-lens reflex (dSLR) camera, you manually extend or retract the lens.
Limitations of Optical Zoom
The primary limitation of optical zoom is that cameras are limited in how far they can zoom. Basic point-and-shoot cameras, for example, might zoom only three times, which is inadequate for photographing objects that are more than a couple dozen feet away. dSLR cameras are more versatile -- an 18-300mm lens can zoom in on objects several hundred feet away -- but it remains that if your lens lacks adequate optical zoom to photograph your desired object, the object will appear small in size.
How Digital Zoom Works
Digital zoom, on the other hand, involves "blowing up" an image to make objects in it appear larger -- the camera does this after you take the picture. You can think of digital zoom as being analogous to cropping a photo -- you essentially select a small part of the field and then augment its size to that of the original field. Digital zoom allows you to increase the size at which objects appear, irrespective of how far you were from them when you took the picture.
Limitations of Digital Zoom
The effectiveness of digital zoom depends on the megapixel resolution of your camera -- in other words, how many dots or pixels it captures per inch. If your camera has a high megapixel resolution, your digital zoom will result in the area of your image you want to highlight being clear and crisp. If it's low in resolution, on the other hand, your digital zoom will produce a blurry image.
Tags: optical zoom, your camera, closer object, digital cameras, digital zoom, Digital Zoom