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I'm not sure that they have any useful depth information. The cameras are very close together.

• 4ad 10y ago
  Some Canon cameras can do phase detection autofocus at f/8. Let's put a 35mm lens on the camera. That means that light rays that are used by the AF system are separated by 4.375mm. Very comparable to the distance between the two iPhone lenses. The way depth information is determined with phase detection autofocus is very similar conceptually with how you'd generate a depth map in software from two separate cameras. Granted, not all cameras can do phase detection AF at f/8, and at 35mm you have enough DOF that the accuracy of the AF is not that critical. But they can do AF at f/5.6 accurate enough for a 50mm lens. That gives you 8.92mm separation. Still comparable to iPhone.
  • dom0 10y ago
    That's not quite how it works. The separation used by the AF is completely fixed by the distance between the (at least two) microlens+aperture+sensor systems that make up an phase AF sensor. The microlens/aperture system of the AF masks essentially the back plane of the lens (which follows from the exit pupil) for the AF sensor (interacting mainly with the exit telecentrism of the lens, which is why AF speed and acccuracy can widely vary with lens type, even if the same f-stop is used). Also a reason (besides the fact that many digital sensor designs perform better with telecentric designs due to increased scattering and reflections in the sensor itself compared to film) why modern lenses are almost always strongly telecentric designs. A completely separate matter is the circle of confusion which is indeed directly related to the aperture of the lens. (I hope I got most of the optical terms correct, I don't normally discuss this topic in English)