Zoom properties of digital cameras
and/or zoom lenses are convenience ways for enlarging or
reducing an image
without the need to get closer or farther away. You'll find
zoom capabilities of digital cameras to be especially useful
for sports and scenic photography or other situations where
your movement is restricted.
Only the least expensive digital
cameras lack zoom features or a zoom lens, and even then,
most have add-on products you can buy to give your camera
zoom capabilities. Some offer only small enlargement ratios,
such as 2:1 or 3:1, in which zooming in closer produces
an image that is twice or three times as big as one produced
when the camera is at its beginning zoom setting. More
cameras have longer zoom ranges, from 4:1 to 10:1 and beyond.
In addition, there are two ways to zoom in on a subject
with a camera offering zoom functions. One is optical zoom,
the camera uses its internal hardware to produce
This produces the
sharpest enlargement during picture taking.
Digital cameras also feature digital zoom, in which the
magnification is produced by using crude interpolation
techniques. Remember from our October
that interpolation is a process that computes pixel color
pixels that already exist and uses that information to produce
the missing pixels in an enlargement. Digital zoom is much
less sharp than optical zoom because digital zoom uses the
crude techniques that photo
enlargement software uses,
bi-cubic interpolation or worse. Indeed, you can get much
better results than most digital zooms by using Imagener
- simply take the picture at your camera's maximum optical zoom
setting, then enlarge the image with Imagener.
Do not confuse optical zoom with digital zoom. Digital zoom
can be used to crop a picture on the camera's screen. To
improve and make more impressive product descriptions,
camera manufacturers sometimes multiply optical zoom by digital
it total zoom. It is a meaningless number and a sales tactic
(see examples to the right). Concentrate on optical zoom
properties when shopping for digital cameras only.