LESSON 2
DEFINE A ZOOM LENS AND ITS OPERATION
TASK
Describe a zoom lens, the principles behind a zoom lens and the operation
thereof.
CONDITIONS
Given information and illustrations about terms relating to the zoom lens,
its principles and operation.
STANDARDS
Demonstrate competency of task skills and knowledge by correctly responding
to 80% of the multiple-choice test covering theory and terminology of the
zoom lens, principles and operations.
REFERENCE:
Course Material, Audio/Television Specialist
Learning Event 1
DEFINE THE ZOOM LENS AND DEPTH OF FIELD
1.
The television camera has three major parts, the camera itself, the
viewfinder, and the lens.
This section will discuss the lens.
All
broadcast-type color cameras are equipped with zoom lenses, or as they are
called in technical language, variable focal-length lenses.
Some of the
older monochrome (black and white) cameras are individual, fixed focal-
length lenses, which are mounted on a turret so that the camera operator can
quickly flip to one of four different lenses. Each one of the four lenses
performs its specific function. Although you will not find any turrets on
modern cameras, we will refer to fixed focal-length lenses because the basic
optical and performance characteristics are more easily explained and
understood. In this lesson, we will discuss these optical characteristics:
focal length, focus, lens aperture, and depth of field.
a. The focal length of a lens determines how wide or narrow a vista a
particular camera has, and how much and in what ways objects appear
magnified. Consequently, we identify lenses by their focal lengths:
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