Shedding light on digital cameras
Back in the 19th century, photography was the newest toy of a
diverse range of documentarians, artists, dilettantes, debutantes, journalists,
and other unlikely animals. Now, at the turn of the 21st century,
digital technology has helped make cameras a brand new toy all over again.
This time around, the focus is not on the picture itself but on what you can
do with it. People are buying up digital cameras like peanuts at the zoo because
they allow the photographer to bypass that pesky development stage (often
lasting a whole hour at one's local photo lab!) and instantly see what he's
shot, virtually as soon as he depresses the magic button. Plus, once the photos
are captured, they can be transferred to computers, to the internet, and thence
to the world. There's no limit to how quickly and easily photos can travel if
they've stored digitally, rather than on rolls of light-sensitive plastic.
Despite the flexibility digital cameras permit, however, they do have their
limitations. Only specific (and more expensive) models will produce quality
prints. The cheaper cameras are better suited to web and e-mail transfer alone.
And price is its own hindrance: you'll still pay significantly more for a
digital camera than you would for its conventional ancestor.
And yet, there is something undeniably appealing in the idea of sitting down
at your PC and dispatching an embarrassing photo of your best friend to all your
mutual acquaintances around the globe -- without, it should be stated, having to
pay the film-developing middle-man a dime. This stuff goes straight from reality
to your camera to your computer to the web. How does it work? Squint hard and
concentrate, and all shall be made clear, almost instantly, below.
When you point a digital camera at the world, the camera doesn't see things
the same way a film camera would. Film is covered with chemicals that get
exposed to light for a split-second and are thereafter indelibly marked with the
image that had been within their frame. In a digital camera, however, light
enters the lens and hits a charge-coupled device (CCD) rather than a film
surface. The CCD is a light-sensitive silicon chip made up of individual
photosensors called pixels. Depending on the quality and price-range of the
digital camera, its CCD holds thousands or millions of these microscopic
Page 2: Pixels and Images