Real Camera Settings
To understand the relationship of the After Effects camerato those of a real-world camera, look again at the Camera
Settings diagram introduced in Figure 9.1. Four numerical
fi elds—Film Size, Focal Length, Zoom, and Angle of
View—surround a common hypotenuse.
A prime (or fi xed) lens would have static values for all four.
A zoom lens would of course work with a fi xed Film Size,
but would allow Zoom and Focal Length to be adjusted,
changing the Angle of View. These four settings, then, are
interrelated and interdependent, as the diagram implies,
and the relationship is just the same as with a real camera,
which the Film Size can even help emulate. Lengthen the
lens by increasing Focal Length and you decrease Angle
of View.
The settings you actually use are Zoom (to animate) and
Angle of View (to match the real-world source).
Angle of View is the radius, in degrees, that fi ts in the view.
If you’re matching it, note that Camera Settings lets you
specify a horizontal, vertical, or diagonal measurement in
the Measure Film Size menu.
In After Effects, the Zoom value is the distance of the
camera, in pixels, from the plane of focus. Create a camera
and its default Z Position is the inverse of the Zoom value,
perfectly framing the contents of the comp at their default
Z Position, 0.0 . This makes for easy reference
when you’re measuring depth of fi eld effects, and it lets
you link camera position and zoom together via expressions
(for depth of fi eld and multiplane effects, discussed later).
