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Current time:0:00Total duration:3:09

Video transcript

hey my name is eben auspey I've been working at Pixar since we were just half a dozen people working on experimental short films one thing that hasn't changed since then is the need for virtual cameras and to understand virtual cameras you need a firm grasp of how physical cameras work and I love cameras in fact I collect them fix and sometimes even build them I built this in a CAD system and printed it out with 3d printing and it takes pictures like that and cameras come in all shapes and sizes like this little baby twin lens and this classic american argus so at pixar when we design a virtual camera our job is to model what happens inside physical cameras have you ever thought about what a camera really does when we take a picture you probably know that a camera captures light on a piece of film or image sensor but to understand how this works let's build a very simple camera we'll start with a box this is our camera body and a single piece of paper which represents our image sensor or film we'll call this the image plane you know what let's do this at a larger scale like using an office as our box our scene is now outside the window and our image plane is the opposite wall we don't see a clear image the problem is any point on our image plane is getting hit by light from everywhere in the scene what we want is for each point on our image plane to be hit by light from a tiny region of the scene look at what happens if we cover up the window except for a little hole we call this small hole the aperture of our camera if you wait a few minutes for your eyes to adjust voila an image the reason it works is because the aperture only lets certain light rays through at this point here on the image plane only light rays from one direction can make it through the aperture and those light rays come from light bouncing off this place in the scene so the aperture is turning out any light rays that don't come from the right direction this simple camera design is known as a pinhole camera if we replace the back wall of the room with a great big sheet of photographic film we could take a great picture that way did you know that the word camera comes from the Latin word for room the first cameras were known as camera obscura meaning darkened room they were in fact room size like our office in the next exercise you can use this pinhole simulator to take some virtual pictures you can adjust the size of your pinhole or aperture and press here to capture an image while doing so you'll have to answer some questions about what's going on such as why is the image flipped and more importantly what happens if we change the size of our aperture see you in a moment