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How a
digital camera works
By Jakob Jelling
Snapjunky.com
The digital camera is not something of a magic box that came
out of the blue and made wonders! The digital camera is very
much like the conventional analog camera, but the technology has
been altered. It also contains most of the associated components
that the conventional camera contains, like lens and a shutter
for letting in light, however instead of reaching a
photosensitive film, the light is made to fall upon array of
image sensors or photosensitive cells. Much of the differences
are like this, yet most of it still remains in oblivion for the
ordinary people. And it order that the digital camera gets its
true respect, it is necessary to explore these areas of truth
and reveal them in light.Looking a bit more in details about
the working of the fantastic device, the digital camera. As a
continuation of the above lines, it can be further investigated
that the sensor array is basically a microchip about 10 mm
across. Every image sensor is a charged-couple device (CCD)
converting light into electric charges, and is essentially a
silicon chip used to measure light. These charges are stored as
analog data that are then converted to digital via a device
called an analog to digital converter (ADC). Over the chip are
present a collection of very small light-sensitive diodes, named
photosites, or pixels that convert light (or more
scientifically, photons) into electrical charges called
electrons. The pixels are very much light sensitive, therefore
with brighter light striking them, produces greater build up of
electrical charges. Each 1000 array receptor creates 1 pixel,
and every pixel corresponds to some information stored. The
light enters the digital camera via the lens, which is the same
mechanism as the conventional analog camera. And this light hits
the CCD when the photographer presses the shutter button. The
shutter opens and thereby illuminates every pixel, however with
various intensities.
Taking a look apart, it can be observed that quite a few
digital cameras use CMOS (meaning complementary metal oxide
semiconductor, a technology of manufacturing these microchips)
technology based microchips as image sensors. The basic
advantage is that the CMOS sensors are appreciably cheaper and
simpler to fabricate than CCDs. Another great advantage from
CMOS sensors is that these take very less power compared to
other technology, which adds up to the fact as to their
extensive use, and can thus even support the implementation of
additional circuitry on the same chip like ADC, some control
units etc. Thus it can be stated that CMOS technology based
cameras are small, light, cheap and also energy efficient, yet
at the cost of some amount of image quality.
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