When a Digital Zoom is Needed
You’ve been warned that you should disregard claims of large digital zoom ratios and have been told that to use a digital zoom is to ruin the picture with visible artifacts and pixels. To a certain extent, these statements are true but they don’t tell the whole story.
Digital cameras that feature an optical zoom and a digital zoom offer the option of using one or the other or even both together. An optical zoom lens of 28 to 200 mm may not be enough in some situations. This is where the digital zoom comes in handy. Say you are at a football game and want to get a close up of your son in action. A 200mm lens setting would probably include three or four football players in the scene, making it difficult to recognize faces.
A two times digital zoom makes the focal length 400 mm, cropping the scene into a two football player picture. A four X digital zoom setting will garner a head and shoulder close up of one football player. At two X digital zoom, the number of pixels are cut in half but digital processing and interpolating between pixels will smooth out the image with very little loss in quality. If your digital camera starts out with 8MB of pixels, the final result of 4MB will still enlarge to over eight by ten size without losing quality.
At four X digital zoom, the pixels are reduced to 2MB which will visibly degrade the image somewhat. This sacrifice in quality is often acceptable if you capture a fantastic shot of action. When artifacts are noticeable in the image, an artifact reducer can do an amazing job in cleaning up the picture. The software works by averaging the smooth areas while retaining the edge sharpness. The sharper the original picture, the better the artifact reducer works. One excellent example is PureImage, offered by a Canadian software company.
Other subjects that would benefit from the use of the digital zoom are bird photography, wild animal photography, candid people shots and sport events of all kinds. While most photographic images are covered with the normal optical zoom range, sometimes the digital zoom can save the day.