in order for an image to be captured on film,
it must be exposed to the light.
A camera uses two things to
control the amount of incoming light (exposure):
A Shutter:
In a camera, the shutter
blocks all light from exposing the film UNTIL you press the button.Then
it quickly opens and closes, giving the film a brief flash of light. You
can control the length of time the shutter remains open by setting the
SHUTTER SPEED.
An Aperture:
When light passes through a
camera's lens, it must pass through an opening
called an "Aperture". In
plain english it's a hole that lets in more light when it's wide open
and less when it's small. Figures, huh? In essence the aperture is just
like the pupil in the human eye. You can control the aperture by setting
the "Aperture Opening", also known as an F-Stop.
Shutter speed:
Determines HOW
LONG the shutter stays open.
 |
Examples:
A half second exposure is ONE STOP darker than
a one second exposure.
A 1/125 exposure is TWO STOPS brighter
than a 1/500 exposure.
A 1/1000 exposure is THREE STOPS darker
than a 1/125 exposure.
The longer exposures ( like 1 second )
give much MORE light to the film than a 1/1000 of a second exposure. So
even though the number may look bigger, don't be deceived! |
Exposure is about different
combination of shutter and f-stop settings. These combination can
drastically affect the finished picture. For example, the following
three pictures have been given an equal amount of light, but the f-stop
and shutter combination make each one unique.
Why is the background all blurred
in the right picture, and sharpest in the left ? Because if the exposure
is made with a wide aperture ( like f2.8 ), then objects farther away
from the subject are thrown farther out of focus.
So... if the aperture is small
(like f22) then objects in the backround (and foreground ) will appear
sharper. However, since more light was required to make the exposure on
the left ( 1/4 Second ) in this example the subjects became blurred from
MOTION.
Below is example of type of the picture that using the shutter speed
Panning
Ligtning trail