Beginners Photography - How Light Works on a Digital Camera Sensor
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Understanding Light and Digital Sensors
By Amy Renfrey
When the shutter opens, it allows light
to enter the camera. The lens reflects the image directly onto the film.
The reflected image tells the film how to record the light
that came through the open shutter.
All of this is affected
by the camera's settings, including the film speed (ISO), aperture
) and shutter speed as
Click for a more detailed explanation of the aperture
Beginners Photography -
Digital photography has a great deal of
the same language and also requires the use of the shutter, ISO and
f-stop, as well as a special medium that is capable of recording the
image in front of the camera accurately.
The digital age
means that no film stock is placed into the body of the camera, and
instead a sensor receives and interprets the data.
effects are created by the camera settings, with the exception of
the interpretation of true colors, and only the recording of the
image takes place in a different manner.
Currently there are
two available devices that are installed within the bodies of
digital cameras as a means of recording images - CCD and CMOS - both
of which are referred to as sensor.
The CCD means
"charge-coupled device" and CMOS translates to "complementary metal
oxide semiconductor" and both result in the same process within the
camera's sensor unit.
Beginners Photography - What is a
Basically the sensor
device is covered by a grid of miniscule electrodes known as
"photosites". Every single digital photograph is composed of the
data translated by photosites, usually called pixels.
Before the camera allows the
shutter to open it charges all of the photosites in the sensor. When
light strikes them they release some of their electrons and the
software within the camera then measures each of the areas of the
grid to record the locations of all of the electrons.
These are then converted
through a special converter which ultimately translates to
pixels and the photographic image that is stored on the camera's
Additionally, the sensor and photosites must be
able to record or understand colors which is accomplished by a
filter applied to the surface of the sensor, and which is capable of
distinguishing a set range of colors within the recorded image.
Beginners Photography - Eliminating the
Understanding how the sensor of a digital
camera works is not as important as understanding the effects
achieved through changing the settings, but it does help to
eliminate any of the mystery around taking photographs in this
popular and rapidly advancing format.
More beginners photography articles!