diff --git a/src/external/viewer.ts b/src/external/viewer.ts
index ee7bf4ac..db7cc61e 100644
--- a/src/external/viewer.ts
+++ b/src/external/viewer.ts
@@ -41,6 +41,14 @@ export { FallbackOptions } from "../viewer/options/FallbackOptions";
 export { UrlOptions } from "../viewer/options/UrlOptions";
 export { ViewerOptions } from "../viewer/options/ViewerOptions";
 
+// Geometry
+export {
+    CameraConstructor,
+    CameraParameters,
+    CameraUniforms,
+    ICamera,
+} from "../geometry/interfaces/ICamera";
+
 // Graph
 export { Image } from "../graph/Image";
 export { NavigationDirection } from "../graph/edge/NavigationDirection";
diff --git a/src/geometry/Camera.ts b/src/geometry/Camera.ts
index 0b5aa8b9..579ba633 100644
--- a/src/geometry/Camera.ts
+++ b/src/geometry/Camera.ts
@@ -8,9 +8,9 @@ export abstract class Camera implements ICamera {
     public readonly parameters: CameraParameters = {};
     public readonly uniforms: CameraUniforms = {};
 
-    public projectToSfmFunction: string;
-
-    constructor(public readonly type: string) { }
+    constructor(
+        public readonly type: string,
+        public readonly projectToSfmFunction: string) { }
 
     public abstract bearingFromSfm(_point: number[]): number[];
     public abstract projectToSfm(_point: number[]): number[];
diff --git a/src/geometry/camera/FisheyeCamera.ts b/src/geometry/camera/FisheyeCamera.ts
index dd2040ee..da3edf33 100644
--- a/src/geometry/camera/FisheyeCamera.ts
+++ b/src/geometry/camera/FisheyeCamera.ts
@@ -97,10 +97,10 @@ vec2 projectToSfm(vec3 bearing, Parameters parameters, Uniforms uniforms) {
 `;
 
 export class FisheyeCamera extends Camera {
-    public readonly projectToSfmFunction: string = FISHEYE_PROJECT_FUNCTION;
-
     constructor(parameters: number[]) {
-        super(FISHEYE_CAMERA_TYPE);
+        super(
+            FISHEYE_CAMERA_TYPE,
+            FISHEYE_PROJECT_FUNCTION);
 
         const [focal, k1, k2] = parameters;
         this.parameters.focal = focal;
diff --git a/src/geometry/camera/PerspectiveCamera.ts b/src/geometry/camera/PerspectiveCamera.ts
index d921b5a3..f225f035 100644
--- a/src/geometry/camera/PerspectiveCamera.ts
+++ b/src/geometry/camera/PerspectiveCamera.ts
@@ -90,10 +90,10 @@ vec2 projectToSfm(vec3 bearing, Parameters parameters, Uniforms uniforms) {
 `;
 
 export class PerspectiveCamera extends Camera {
-    public readonly projectToSfmFunction: string = PERSPECTIVE_PROJECT_FUNCTION;
-
     constructor(parameters: number[]) {
-        super(PERSPECTIVE_CAMERA_TYPE);
+        super(
+            PERSPECTIVE_CAMERA_TYPE,
+            PERSPECTIVE_PROJECT_FUNCTION);
 
         const [focal, k1, k2] = parameters;
         this.parameters.focal = focal;
diff --git a/src/geometry/camera/SphericalCamera.ts b/src/geometry/camera/SphericalCamera.ts
index 457827f0..02224c35 100644
--- a/src/geometry/camera/SphericalCamera.ts
+++ b/src/geometry/camera/SphericalCamera.ts
@@ -43,9 +43,11 @@ vec2 projectToSfm(vec3 bearing) {
 `;
 
 export class SphericalCamera extends Camera {
-    public readonly projectToSfmFunction: string = SPHERICAL_PROJECT_FUNCTION;
-
-    constructor() { super(SPHERICAL_CAMERA_TYPE); }
+    constructor() {
+        super(
+            SPHERICAL_CAMERA_TYPE,
+            SPHERICAL_PROJECT_FUNCTION);
+    }
 
     public bearingFromSfm(point: number[]): number[] {
         return bearing(point);
diff --git a/src/geometry/interfaces/ICamera.ts b/src/geometry/interfaces/ICamera.ts
index d319fa72..42734b34 100644
--- a/src/geometry/interfaces/ICamera.ts
+++ b/src/geometry/interfaces/ICamera.ts
@@ -1,6 +1,19 @@
 export type CameraParameters = { [key: string]: number; };
+
 export type CameraUniforms = { [key: string]: boolean | number | number[]; };
 
+/**
+ * @interface
+ *
+ * @description Interface for cameras. This is a
+ * specification for implementers to model: it is not
+ * an exported method or class.
+ *
+ * Implmenting a custom camera allows the implementer to
+ * render textures and camera frustums with proper undistortion.
+ *
+ * Custom cameras must have a unique type.
+ */
 export interface ICamera {
     readonly type: string;
 
@@ -12,3 +25,7 @@ export interface ICamera {
     bearingFromSfm(point: number[]): number[];
     projectToSfm(bearing: number[]): number[];
 }
+
+export interface CameraConstructor {
+    new(parameters: number[]): ICamera;
+};
diff --git a/src/viewer/ProjectionService.ts b/src/viewer/ProjectionService.ts
index 6d48df19..614d3216 100644
--- a/src/viewer/ProjectionService.ts
+++ b/src/viewer/ProjectionService.ts
@@ -10,13 +10,14 @@ import {
     SphericalCamera,
     SPHERICAL_CAMERA_TYPE,
 } from "../geometry/camera/SphericalCamera";
-import { ICamera } from "../geometry/interfaces/ICamera";
+import {
+    CameraConstructor,
+    ICamera,
+} from "../geometry/interfaces/ICamera";
 import { ICameraFactory } from "../geometry/interfaces/ICameraFactory";
 
-export type CameraCtor = { new(parameters: number[]): ICamera; };
-
 export class ProjectionService implements ICameraFactory {
-    private readonly _cameraFactory: { [type: string]: CameraCtor; } = {};
+    private readonly _cameraFactory: { [type: string]: CameraConstructor; } = {};
 
     constructor() {
         this.registerCamera(
@@ -30,7 +31,7 @@ export class ProjectionService implements ICameraFactory {
             SphericalCamera);
     }
 
-    public registerCamera(type: string, ctor: CameraCtor): void {
+    public registerCamera(type: string, ctor: CameraConstructor): void {
         this._cameraFactory[type] = ctor;
     }
 
@@ -38,6 +39,7 @@ export class ProjectionService implements ICameraFactory {
         if (!(type in this._cameraFactory)) {
             return new PerspectiveCamera([0.85, 0, 0]);
         }
+
         return new this._cameraFactory[type](parameters);
     }
 }
diff --git a/src/viewer/Viewer.ts b/src/viewer/Viewer.ts
index a1f79dbe..0ee6cd8b 100644
--- a/src/viewer/Viewer.ts
+++ b/src/viewer/Viewer.ts
@@ -49,7 +49,7 @@ import { cameraControlsToState } from "./Modes";
 import { ViewerReferenceEvent } from "./events/ViewerReferenceEvent";
 import { IDataProvider } from "../external/api";
 import { ViewerResetEvent } from "./events/ViewerResetEvent";
-import { ICamera } from "../geometry/interfaces/ICamera";
+import { CameraConstructor } from "../geometry/interfaces/ICamera";
 
 /**
  * @class Viewer
@@ -1486,7 +1486,7 @@ export class Viewer extends EventEmitter implements IViewer {
      */
     public registerCamera(
         type: string,
-        ctor: { new(parameters: number[]): ICamera; }): void {
+        ctor: CameraConstructor): void {
         this._navigator.projectionService.registerCamera(type, ctor);
     }