Adobe After Effects CS4 - Manual (Page 681)

675 USING AFTER EFFECTS CS4
Expressions
Last updated 12/21/2009
Camera attributes and methods (expression reference)
Camera objects have the same attributes and methods as Layer objects, except for source , effect , mask , width ,
height , anchorPoint , scale , opacity , audioLevels , timeRemap , and all of the material properties.
pointOfInterest Return type: Property [3].
Returns the point of interest values of a camera in world space.
zoom Return type: Property.
Returns the zoom values of a camera in pixels.
Here’s an expression for the Scale property of a layer that maintains the relative size of the layer in frame while
changing the z position (depth) of a layer or the Zoom value of a camera:
cam = thisComp.activeCamera;
distance = length(sub(position, cam.position));
scale * distance / cam.zoom;
depthOfField Return type: Property.
Returns 1 if the Depth Of Field property of a camera is on, or returns 0 if the Depth Of Field property is off.
focusDistance Return type: Property.
Returns the focus distance value of a camera, in pixels.
aperture Return type: Property.
Returns the aperture value of a camera, in pixels.
blurLevel Return type: Property.
Returns the blur level value of a camera as a percentage.
active Return type: Boolean.
Returns true if the camera is the active camera for the composition at the current time: the Video switch for the
camera layer is on, the current time is in the range from the In point of the camera layer to the Out point of the camera
layer, and it is the first (topmost) such camera layer listed in the Timeline panel. Returns false otherwise.
More Help topics
“ Cameras, lights, and points of interest ” on page 186
Light attributes and methods (expression reference)
Light objects have the same attributes and methods as Layer objects, except for source , effect , mask , width , height ,
anchorPoint , scale , opacity , audioLevels , timeRemap , and all of the material properties.
pointOfInterest Return type: Property [3].
Returns the point of interest values for a light in world space.
intensity Return type: Property.
Returns the intensity values of a light as a percentage.
color Return type: Property [4].
Returns the color value of a light.
coneAngle Return type: Property.