260Cameras are everywhere. Cell phones often include
them, they are used in security systems, in space
exploration, medical equipment, and in
speed cameras. Cameras are devices that
capture still or moving images.
MEMORY
CARDS can store
thousands of digital images.Through a lens
Tenth century
The concept of a camera obscura is credited
to Abu Ali Al-Hasan. It works by light
passing through a hole and hitting a surface,
where it forms an upside-down image. In
later models mirrors were used to reflect the
image so that it appeared the right way up.1500sā1800s
Artists used more developed
camera obscuras to trace images
of scenes onto paper. The
invention of the camera obscura
led to the development of
modern-day cameras.1840s
Simple photographic cameras
were in use by the 1840s and
were little more than a wooden
box with a hole cut to hold a
lens. Images were recorded on
a glass or metal plate.TAKE A LOOK: SENSOR
A digital camera requires a sensor in order to
work. A shutter allows light to pass through
the lens to a sensor. The sensor is a grid of
millions of pixels.Each pixel measures the amount of light that
hits it through a green, blue, or red filter.The measurements are changed into digital
information that is used to make the final
digital image.TECHNOLOGY
TIMELINE OF CAMERAS
GOING DIGITAL
Digital cameras are similar to film
cameras except that they store the
images on a memory card. Their
lenses focus the image onto an
electronic sensor (CCD or CMOS)
that converts the light into electrical
charges. The charges are measured
to give digital values. Computer
chips process the data to construct
the image, which is then stored on
a memory card.1880s
Photographic film was made in the
1880s. It was made from a strip of plastic
coated with crystals of a silver compound.
Cameras were developed to include an
automatic shutter mechanism allowing
the right amount of light in the lens.Autofocus system
makes sure an image
is clear.An inbuilt flash
provides light when
it is too dark to take
a photo.A control dial allows
the photographer to have
control over settings.A circuit board processes information
from the sensor into a digital format.The digital screen
lets the user check
and review images.(c) 2012 Dorling Kindersley. All Rights Reserved.(c) 2012 Dorling Kindersley. All Rights Reserved.