2. A device that controls the
amount of light admitted
through an opening. In
photography and digital
photography, aperture is the
unit of measurement that
defines the size of the
opening in the lens that can
be adjusted to control the
amount of light reaching the
film or digital sensor. The
size of the aperture is
measured in F-stop.

3. F/4.5
Here we can see that the
picture is over exposed in
terms of light. We can see
this picture had an 4.5 in
terms of ISO, which means
that it gathered up more
light in the camera.
F/29
From the first picture we
can see that this one isn’t
exposed in terms of light.
The count of the ISO is
higher which means it’s
generally darker in terms of
the light passing through
the camera.
F/29
From this picture we can see that it
is the same as the middle picture
in terms of the ISO. The only
difference in these 3 pictures is
that the first picture has low ISO,
generally making the picture much
lighter.

4. In photography and digital
photography the shutter speed is the
unit of measurement which
determines how long shutter remains
open as the picture is taken. The
slower the shutter speed, the longer
the exposure time. The shutter speed
and aperture together control the
total amount of light reaching the
sensor. Shutter speeds are expressed
in seconds or fractions of a second.
For example 2, 1, 1/2, 1/4, 1/8,
1/15, 1/30, 1/60, 1/125, 1/250,
1/500, 1/1000, 1/2000, 1/4000,
1/8000. Each speed increment halves
the amount of light.

5. In Digital Photography ISO measures
the sensitivity of the image sensor.
The same principles apply as in film
photography the lower the number
the less sensitive your camera is to
light and the finer the grain.
Higher ISO settings are generally
used in darker situations to get
faster shutter speeds. For example
an indoor sports event when you
want to freeze the action in lower
light. However the higher the ISO
you choose the noisier shots you will
get.