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Understanding how a camera works and how
does a camera functions. Essentially, a camera is a dark box
having a hole in one end covered by a glass lens. Either inside the
lens, or in the back of it is a shielding device called a shutter. At
the back of the box is a piece of photodiode sensors on which
image/light is received before it is translated to digital signal.
The purpose of the shutter is, first of all, to keep the inside of the
box in pitch darkness so that no light reaches the sensor. The only
time the shutter is open is when an exposure is being made.
This is what happen when the lever on the outside of the camera is
tripped for making an instantaneous exposure:
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The shutter opens to permit light to
enter the camera.
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Rays of light reflected by the subject
pass through the lens and through a circular opening called a diaphragm
on their way to the sensor.
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The shutter closes automatically.
In the fraction of a second that elapses
between the opening and closing of the shutter, the "working heart" of
the camera does its job. The shutter controls "how long" the light will
be permitted to enter the camera. The diaphragm opening controls "how
much" light will be allowed to enter during the given interval of time.
The lens bends the rays of light so that the light reaches the sensor
of the camera.
The interaction between the shutter, diaphragm, lens and sensor can be
comparable to the way our human eye functions.
Lens functions as the human eye's pupil. It controls the opening
through which light rays enter.
Diaphragm functions as human eye's iris. It is mainly about the opening
which control "how much" light can enter during a given interval of
time
Shutter functions as human eye's eye lid in which it keeps the interior
dark when closed and also controls how long light can enter during an
exposure.
Sensors is like our human eye's retina where all the light rays are
recorded to show their impressions.
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