Chapter 4 Video Camera Operations
87
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Factors Affecting Depth of Field
• Aperture—The size of the opening in the lens that allows light into
the camera. The larger the opening, the smaller the depth of fi eld and
vice versa.
• Subject to camera distance—The distance between the camera and
the subject of the shot. The closer your camera is to your subject, the
smaller the depth of fi eld and vice versa.
• Focal length—The amount the lens is zoomed in or out. The more
you are zoomed in, the smaller the depth of fi eld and vice versa.
Remember: The f-stop indicates the size of the iris, which
creates the size of the aperture. The bigger the f-stop number,
the smaller the aperture.
Production Note
More movement in each of these three areas creates a more pronounced
effect for either shallow or great DOF, Figure 4-7. For example, the effect on
DOF produced by zooming in and increasing aperture size is not as great
as when the camera moves closer to the subject in addition to zooming in
and increasing aperture size.
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Depth of Field
Director’s
Goal
Zoom
Technique
Dolly
Technique F-Stop Setting
Obtain a
shallow
depth of
field.
Zoom In Dolly In
Use a lower f-stop value:
• Reduces the iris
• Increases the aperture; more
light passes through the lens
Obtain a
great depth
of field.
Zoom Out Dolly Out
Use a higher f-stop value:
• Enlarges the iris
• Decreases the aperture; less
light passes through the lens
Figure 4-7. Depth of field
chart.
Camera lenses are operated by camera operators. Even though depth
of fi eld involves manipulating light, the lighting designer does not have a
part in this process. The camera operator creates depth of fi eld by manipu-
lating the lens. Set lighting does not affect depth of fi eld. Depth of fi eld
is affected by subject to camera distance, focal length, and aperture (not
light). Understanding how to effectively use depth of fi eld is a valuable
tool that can greatly affect the impact and power of a scene for the viewer.
Since the majority of scenes in typical programs are shot using a
great depth of fi eld, a smaller aperture is more commonly used. A smaller
aperture requires higher light levels to capture a good quality picture. This
is why there are so many bright lights on the ceiling of a production studio.
Studio sets are saturated with light, which allows the aperture of cameras
to be reduced when necessary without affecting the picture quality.