The most used controls in a camera:
1.
Iris: The ring closest to the camera body
controls the amount of light passing through the lens to the light- sensitive
surface of the pickup tube or chip. It is called the iris, aperture or f-stop
control and is marked off in f-numbers. The lowest f-stop lets in the most
light and the highest f-stop lets in the least. Some lenses even have a ‘C’
setting after the highest f-stop which means the lens is completely closed,
letting no light through at all. The standard f- numbers are 1, 1.4, 2, 2.8, 4,
5.6, 8, 11, 16, 22 and 32 where 1 allows the most amount of light and 32 allows
the least amount of light to pass through the lens.
2.
Zoom: The centre ring on most lenses is the zoom
control. This allows you to change the focal length of the lens through a range
from wide angle (short focal length) to telephoto (long focal length). It is
common for inexpensive zoom lenses to have a range of about six to one. This
means that the longest focal length is about six times the shortest. The main
use of the lens is in controlling the field of view of the camera when it is
inconvenient or impossible to change the distance from the subject to the
camera.
3.
Focus: The focus is used to control the depth of
field. Depth of field is the range of distances in front of the lens in which
objects appear to be in acceptable focus. It is longer for short lenses and it
increases as you use higher f-stops. It is preferable to use a higher f-stop
when lighting conditions permit, if you expect the distance between the camera
and the subject to change often while you are taping, since you will have less
trouble keeping the subject sharply focused with greater depth of field.
4.
White Balance: If you use outdoor film with
normal indoor lighting (no flash) everything comes out orange. In professional
cameras, it may be necessary with each change in location or lighting to make
the camera interpret a particular colour. This is done by showing the camera a
white platform ( sheets, walls, desks etc.) which represents the total absence
of colour. Controls on the camera are then used to minimize the colour output
of the camera.
