When writing an article on the intrinsic camera matrix, I created a diagram to illustrate various properties of the pinhole camera. I've made the Adobe Illustrator source file available under a creative commons license. My hope is that others can use this for instructional purposes and hopefully improve upon it. Feel free to modify it to your needs, and if you use it in your project, I'd love to hear about it.
The file is split into several layers, which include
You can use the "saved views" feature in Illustrator to see some example configurations, which you can see below.
Basic pinhole camera.
Focal length
Principal point and axis
Principal point offset
Principal point offset, shifted pinhole
Principal point offset, shifted film
Pinhole camera with frustum
Frustum only, with true image plane
Frustum only, virtual image plane only.