Extendscript: Get After Effects Camera Data

aeCameraData.jsx

// Figuring out some math to determine aov, filmSize and focalLength in an AE camera, as these values aren't script-accessible.
// Assuming units are pixels, film size measuring horizontally

var comp = app.project.activeItem;
var camera = your camera layer;

var compSize = comp.width;
var cameraZoom = camera.zoom;
var depthOfField = camera.depthOfField;
var focusDistance = camera.focusDistance;

var aov = 2 * Math.atan(compSize / (2 * cameraZoom));

// given focalLength, get filmSize:
var filmSize = 2 * focalLength * Math.tan(aov / 2);

// OR: given filmSize, get focalLength:
var focalLength = cameraZoom * filmSize / compSize;